Speaking Over Coffee

Does temperature matter in batch brewing?

2020-11-27T09:38:00.015+00:00

The temperature has always been a major variable in extraction. It's one of the first taught to trainee baristas. It's also very instinctive

However, it's more complicated when we try to understand its impact on the flavour profile isolated from the extraction. We've all heard someone saying too hot water can burn coffee - whatever that actually means. So what's the deal with the temperature?

This article is a summary of a new study by the UC Davis Coffee Center. It's free to access so I encourage everyone to have a look:

Brew temperature, at fixed brew strength and extraction, has little impact on the sensory profile of drip brew coffee.

It's a bold title since it has only tested 3-litre batch brewing within a limited range of temperatures. But I'm getting ahead of myself.

Before dissecting the paper I'm going to outline the basic theory on temperature for context. In the end, you will find my opinion on the narrative and methods of the research.

Temperature as a variable

Temperature influences the speed of extraction (how quickly compounds dissolve in water). It affects what is being extracted - for example, some compounds are not soluble in water at room temperature - think the less acidic flavour profile of cold brew (Cordoba, 2019).

As we move into very high temperatures, the polarity of compounds comes into play. Water is polar and thus easily extracts other polar compounds. The majority of coffee solubles are polar. But roasty, smoky, acrid flavours are generally non-polar. They need much more energy to be extracted. You get more of them as the temperature gets closer to 100°C (Lopez, 2016). That's why darker roasts taste better with a lower brew temperature.

A slurry temperature in a batch brew

The temperature of the water is only one part. What is actually important is the slurry temperature and its stability. And that is only partially affected by the brewing water. To name just a few other factors:

the temperature of the ground coffee,
how well preheated is the brewing basket,
the material and design of the brewer,
cumulative mass of slurry,
pulses setting.

Batch brewing places lower importance on the temperature of brewing water. The mass of brewing water in the batch brew is much greater than single-cup V60 - it will lose its hear more slowly. It will also be more resilient to ambient temperature and draughts. The length of the brewing is much longer too, thus the speed of extraction matters less.

With that context, we can now look into the study.

The goal of the research

This study is part of a bigger project looking into TDS and extraction percentage (PE). To quote from a bio of one of the authors, Mackenzie Batali:

"Her work focused on using descriptive sensory techniques to expand and update the classic Coffee Brewing Control Chart for the coffee industry. The goal is to quantify how flavor profiles change with different variables in different brewing methods, to create a more specific and scientifically-based Coffee Brewing Control Chart" [edited for clarity]

Previously the UC Davis Coffee Center published other studies focusing on the factors of sensory profile on coffee. Such as effect of basket geometry (Frost, 2019), brew development over time (Batali, 2020) and effects of strength, yield and roast level (Frost, 2020). The last one is very similar in the design to this study. In summary it tested different combinations of TDS and PE, using the same Curtis G4 brewer with 3075ml batch at 90.5°C. The critical variable was roast level (light, medium, dark). It might explain why having established the effects of roast this paper doesn't vary roast level. Although I suspect combining roast and brewing temperature as variables might affect the sensory profile to a great extent.

Study design

The strength and extraction percentage were isolated. To achieve that, different temperature setpoints were offset with other variables.

Coffee was brewed at each zone of the Coffee Control Chart for each temperature (87°C, 90°C and 93°C). That produced 27 type samples.

The total of 270 batches was measured and plotted on this graph:

As you can see there is a wide range of extraction levels from over 15% to nearly 27%. TDS varied from 0.9% to 1.7%.

31 attributes - 3 aromas, 22 flavours, 2 mouthfeels, and 4 basic tastes were evaluated by a team of 12 trained panellists.

The statistically significant attributes were plotted on this spider graph:

Results

The strength (TDS) has the biggest impact on the flavour profile, followed by Extraction Percentage. Across combinations of TDS and PE, the temperature didn't have a significant impact on the sensory profile.

A very interesting aspect of this study is correlating attributes with TDS and PE. This provides a scientific basis for extraction theory.

The Response Surface Methodology produced contour plots which are intuitive and easy to apply in real-life. It identified sensory extraction markers. That wouldn't be possible without advanced data science methods.

The results provide a strong scientific basis for understanding how the sensory profile is impacted by TDS and PE. It's certainly a better model than Lockhart's Brewing Chart.

Methods and limitations of the study - my opinion

Now that we've covered the major points of the study, let's have a closer look at technical details.

The recipe. All samples are detailed here. However, just to give you an idea what we're working with I've extracted the ranges for each variable:

Target TDS: 1% - 1.5 %

Target PE: 16% - 24%

Temperature: 87° - 93°C

Dose: 119 - 265 g

Brewing water: 3075 ml

Brewing ratio: 11.7 - 25.8

Grind size (Mahlkonig Guatemala): 3 - 5

Brew duration: 6:12 - 11 min

Brew pulses: 2 - 10

Let's discuss some of them.

First, the temperature range. 87°-93°C. I would barely call that a range for reasons I explained at the very beginning of this article. In batch brewing, even light roasts extract well around 90°C if the brewing cycle is long enough, without dramatic effects on acidity levels. I suppose the 3-litre batch could manage the 87°C, especially given the development of the roast. Therefore I can't imagine this range to produce vastly different flavour profiles.

They could go lower, but I'm particularly interested in the temperatures above 93°C. That could change the key findings on temperature. The authors might be aware of it since it's been mentioned in the introduction of the paper. But it would be super interesting.

Unfortunately, the brewer - Curtis G4 was partly at fault. To quote Professor Ristenpart: "93°C was the highest we could reproducibly achieve for the large volumes of coffee needed for the trained panel assessment".

The equipment was donated by Wilbur Curtis. Thus the choice of the brewer was not elicited by the study design.

Breville Corporation, which provided support for this research had an interest. As a producer of home brewers it benefits from the study. It's easier to manufacture equipment operating at lower temperatures. The use of energy and carbon footprint are certainly a concern as well. But I think the SCA Gold Cup certification standard - a minimum of 92°C is the main concern. Thus, I can understand why other equipment allowing higher temperatures wasn't sought.

I've never used Curtis G4, but I heard it has poor water dispersion and basket design. That is known to cause astringency and low flavour clarity. It is purely my speculation, but if that's true it could undermine the results.

Roasting. "Green coffee was mixed then roasted in a Loring S35 Kestral in 29 kg batches for an 11:29 (minutes:seconds) total roast time, with first crack recorded at 9:00 and a 2:30 development time". There's nothing unusual about it. I can't speculate about the development since the water details are confusing. Though 2:30 seems to be a fairly long development time for filter coffee, but I understand it's based on the US market. Testing different roasting styles would certainly benefit the study.

The roasting curve below (I've added conversions into Celsius):

Water specification is published in great detail, but I'm not sure if it's correct. I've emailed the authors about it, but at the time of writing, there was no reply.

"Brewing water was prepared by dissolving 1.16 g CaSO4·2H2O, 4.97 g MgSO4, 3.26 g NaHCO3, and 2.57 g KHCO3 per litre of deionized water" - that seems very hard, more like a composition of a concentrate you would then dilute with deionised water to make up brewing water.

Using this calculator, I came up with these values:

I wouldn't want to put that water in any water heating device, let alone drink coffee brewed with this. I will update this part of the article as soon as I get a response.

It would be great to have different water compositions used for this study.

Grinding. Mahlkonig Guatemala grinder was used (it has a dial numbered 1-7 for context).

3 grind settings were used:

"3", average particle grind size 770 ± 10 µm
"4", average particle grind size 928 ± 3 µm
"5", average particle grind size 1115 ± 74 µm

3075 ml batch requires a very coarse grind setting for any reasonable results. I would certainly try to stick to the upper 20% of the range (5.5-7). The 770-micron particle size for 3075 ml proves poor extractability in this setting. I wonder whether the data provided is simplified or they have actually used such big steps (from 3 to 4) without any intermediate settings.

Using an effect of basket geometry study (Frost, 2019) for context, with the same grinder, the same range of settings was used. Although in that study the batch size was much smaller. 1200 ml of brewing water at 95°C for 66 g of coffee. Even though Breville Precision brewer was used, I can't imagine how 3075 and 1200 ml batch could successfully use the same grind size.

The coffee used was a washed Honduras from Marcala, La Paz. No other coffee was used for the testing.

Conclusion

I don't want to attack the paper or the authors. It's a good study. This research is needed. I'm impressed with the use of Principal Component Analysis and Response Surface Methodology. These techniques simplify the complexity of multiple brew variables and allow to show them in an intuitive way. It's an advanced data science applied to coffee allowing anyone to understand it, i.e. the contour plots. That's exactly what most coffee folks can't do themselves.

The sensory correlations with TDS and PE lead to a better scientific understanding of dialling-in. It's much better than the original Coffee Brewing Chart. I can totally see myself using a version of the contour plots in a sensory training session.

My main concern is the clickbait-like title of the study. The temperature findings apply to a very limited range of scenarios. It has limited implications for the industry.

I believe the narrative around the study is a bit too bold. Using an example from an interview with Ristenpart: "If those metrics [TDS and PE] are the same in two different brews, it doesn’t matter what brew temperatures were used to achieve them because tasters can’t differentiate them: they taste the same” - I would urge to be more careful with that statement - based on this research I agree with this sentence only for batch brewing (over 3 l) in a very narrow range of temperatures (87°-93°C).

I'm not sure if the interest of supporting companies (Breville, Curtis) had any influence on that. But even if, I'd be the first to defend that.

This study is free access - that means significant cost researchers have to pay if they want their paper published in a reputable journal. Any support makes that easier. I'd argue democratising access to scientific research is more important than the narrative.

References:

1. Cordoba, N., Pataquiva, L., Osorio, C. et al. (2019) Effect of grinding, extraction time and type of coffee on the physicochemical and flavour characteristics of cold brew coffee. Sci Rep 9, 8440

2. José A. Sánchez López, Marco Wellinger, Alexia N. Gloess, Ralf Zimmermann, Chahan Yeretzian. (2016) Extraction kinetics of coffee aroma compounds using a semi-automatic machine: On-line analysis by PTR-ToF-MS. International Journal of Mass Spectrometry, Volume 401

3. Frost, S.C., Ristenpart, W.D. and Guinard, J.‐X. (2019), Effect of Basket Geometry on the Sensory Quality and Consumer Acceptance of Drip Brewed Coffee. Journal of Food Science, 84: 2297-2312.

4. Batali, M.E., Frost, S.C., Lebrilla, C.B., Ristenpart, W.D. and Guinard, J.‐X. (2020), Sensory and monosaccharide analysis of drip brew coffee fractions versus brewing time. J Sci Food Agric, 100: 2953-2962

5. Frost, S.C., Ristenpart, W.D. and Guinard, J.‐X. (2020), Effects of brew strength, brew yield, and roast on the sensory quality of drip brewed coffee. Journal of Food Science, 85: 2530-2543

Images:

Title Photo by earlybird coffee on Unsplash

Graphics as figures 2, 4, 6 and S3 (edited) from the paper

LIPID RESISTANCE PART II: TESTING

2020-06-28T10:12:00.000+01:00

After coming up with a hypothesis on heat resistance, I needed to find if and how it changes. In this post, I will describe the details and methods as well as present the results. If you've not read the first part, I encourage you to read that first.

Click here for part 1

Is it possible that coffee lipids affect resistance?
There are many factors influencing bed resistance. The most obvious is a grind size - the burr aperture defining average particle size. Finer grind setting increases resistance.

The temperature of the beans affects the Particle Size Distribution (PSD). For a given burr aperture you get different results with different bean temperatures. Cold beans when ground result in smaller fines, but there's more of them (Uman, 2016). The fluctuations in PSD are very likely to occur in the cafe throughout the day.

Freshly roasted coffee contains more Carbon Dioxide. During the extraction, the CO2 is released from the coffee acting as a counterforce to pressure. This results in increased resistance, forcing the barista to use a courser grind size to offset the effect. Well-degassed coffee allows you to grind finer and thus increase your extraction.

Interestingly, a similar effect occurs when the brewing water already contains Carbon Dioxide (Wellinger, 2017). It will depend on your filtration system. I've dedicated an entire article on the subject - read it here.

It's important to understand the equipment and its settings as well. Flow restrictors, pre-infusion chambers and filter basket design will affect the resistance.

Pump pressure could influence it too. Very high pressures will compress the coffee cake to the point it's almost impenetrable to water. Thus lower pressures allow finer grind settings.

There are more factors in bed resistance, such as the loss of volatile compounds (mentioned in the previous post) or environmental factors. However, there's little or no research on that.

This article is limited to the heat (temperature) of ground coffee and its impact on bed resistance. My research has been motivated by finding the thermal role of lipids in ground coffee texture. I've also formed a hypothesis linking it directly to resistance:

As the temperature of the grinds increases and the lipids transform into a liquid state the resistance increases due to that transition.

Equipment and Coffee
The espresso machine used for the testing was La Marzocco GS3. It was set to 9 bar of pressure and 93°C brewing water temperature. It was equipped with a standard 17g La Marzocco basket.

The water was filtered using an ion-exchange cartridge resulting in 160ppm (using conductivity meter).

The grinder was Victoria Arduino Mythos 1. For some part of the testing, the fans were covered to induce overheating. The hopper was filled with at least 700g and no more than 1000g of coffee during the testing for consistent pressure in the feeding chute.

For the most part, the grinder was switched on with heating element plugged in at least 20 min before using (to allow it to preheat). However, part of the data was obtained using a cold grinder with the element unplugged.

Prior to data collection, the grinder was dialled in using 16.5g dose to 35g yield and 35s of contact time for each dataset. The grind setting and grinding time were not adjusted during the tests.

3 different coffees were used:

1. Guatemala, Bourbon variety, Natural process
Days after roast: 171
Roast: medium for espresso, 12 min
Agtron: Whole bean - 40.9, Ground - 47.2

2. Blend (post-roast):
- Brazil, Yellow Bourbon, Natural
- El Salvador, Bourbon, Natural
Days after roast: 196
Roast: medium for espresso, 12 min (both components), Agtron: Whole bean - 41, Ground - 47.3

3. Brazil, Yellow Bourbon, Natural
Days after roast: 12
Roast: medium for espresso, fast start, 11:30 min
Agtron: Whole bean - 42.9, Ground - 47.1

I've used very fresh and relatively old coffee to test whether CO2 influences the path of resistance. Analysing the data I didn't notice a difference.

How did I measure the heat and why?
With this particular setup, I've noticed some interesting things.
The frictional heat per 16.5g dose adds about 10°C of heat to coffee. When the grinder is cold and the burrs are at room temperature, beans at 25°C will result in 35°C grounds. Also, the temperature will be uniform across the ground dose - that changes as you grind more coffee.

As the grinder is used, the heat will be also absorbed by the burrs. These, in turn, will heat the grounds as they pass the grinding chamber. This plus the frictional heat result in much higher ground coffee T than bean T. Also, the difference between the first few grams and the last few will increase. I call this a thermal gradient.

The gradient averages at 10°C across many different temperature points. However, it gets closer to 15°C if the grinder is not used for more than 2 min - I suppose the coffee inside the grinding chamber absorbs more heat.

Therefore I decided to use the highest reading (the very last gram ground) from the top of the grounds pile in the basket as a Temperature reading. I think it's safe to assume the average dose T is 5°C lower (based on a gradient of 10°C).

The measurements were taken using an infrared thermometer. It's important to remember that temperature readings are difficult to compare. That is due to the instruments, their placement, technique or calibration. Rather than focusing on strict values, I'd encourage you to look at the intensity and direction of change.

Test: how temperature (T) affects resistance

First, I wanted to find the point of increasing resistance. I define the resistance increase as an increase in contact time since all other variables stay constant. In my dataset, it happens around 45°C. This corresponds with the research quoted in the first part (Illy, 2005). The dataset could be statistically described using metrics. For temperature (T):

The T values range from 36 to 75, with the vast majority falling into the 50-55 range. This temperature spectrum is easy to maintain with the Mythos. The cooling system is highly effective when pulling 1 shot every 2 minutes. To reach higher T, I had to inhibit the fans and grind large amounts of coffee prior to data collection.

And contact time (t):

Secondly, I wanted to track the change across the temperatures. Including very low values of T - when the grinder is cold, as well as very high values when the grinder is overheated. You can see the data-based trend line below:

In the background - average values for each T value. In the front - trend line as a polynomial function.

This trend line is extremely important. Michael Cameron has drawn the first part up to the first local maximum (Cameron, 2016). So that only confirms his findings but also shows what happens above 60°C.

Initially, the resistance is relatively high. As the grinder warms up and the grounds temperature increases, the resistance goes down. It plateaus between 40°C and 45°C and then increases, reaching a peak around 60°C. Temperatures above 60°C result in decreasing resistance. Note that this temperature is only possible to reach with Mythos 1 when pushing it above its capacity.

Each coffee produced a very similar path of resistance. The graph above combines all 3 for the maximum range representation.

Grinder's thermal energy
Why grinders produce so much heat and why you should manage it? Fast grinding for espresso requires a lot of energy. Much of that energy is transformed into heat. Resistance and extraction are linked to thermal energy. If not for the continuous change in grind profile, espresso would be super-consistent. 2 espressos can taste differently even at the same contact time. Usually though, controlling that variable is challenging and never stops.

Frictional heat is correlated with the grinding time. I've explored the effect of grinding time on the temperature in this post from 2017. In short, higher doses take more time to grind and this contributes greatly to overheating. Finer grind setting requires longer grinding time, which produces more heat. But I'm not sure if the aperture of the burrs has a thermal impact in itself.

As more coffee is ground, the grinder is progressively getting hotter. The temperature in the grinding chamber has a big impact on the final ground coffee temperature. The heat is transferred to coffee as it passes the chamber.

It's not only friction but also the thermal energy of the grinder causing grounds temperature to increase.

If you use Mythos, the chamber is kept at around 35°C. That could mean that you never get grounds below 40 degrees. I'd argue that's a good thing. It helps avoid the initial decrease of the resistance, allowing the barista to make fewer grind changes. Also, the temperature of extraction is kept within a smaller range.

You could keep the heating element unplugged. It will slow the approach towards increasing resistance and overheating.
But even then it will quickly climb up to 50°C and above due to frictional heat. Then fans will try to keep it below 55°C.

Bean temperature and volatiles
I used only room temperature beans. On hotter days you might approach the increasing resistance point sooner. But the effect of bean temperature on final grounds temperature is minimal. The grinder's heat and frictional heat have much more influence.

What's noticeable though is the change in Particle Size Distribution. Through PSD, resistance depends on bean temperature. Different bean temperature could produce a similar path of resistance, but the changes in the trend might occur at different temperature points.

I suppose part of the decrease in the resistance after 60°C mark can be attributed to beans warming up from the overheating grinder. It would be worth to do further testing isolating that as a variable or putting the probe in the hopper to measure the effect.

Other than that I could only think of the loss of volatiles. Which can occur already in the grinding chamber, where the heat would catalyse the process.

Conclusions and limitations
I managed to establish how the resistance changes across the temperatures. I couldn't confirm whether the lipids are responsible for the increase in resistance around 40°C. But in line with the previous research on lipids becoming fluid around 40°C, there's a strong correlation.

Why would lipids influence that is still unclear to me.

Aside from surface texture and PSD, escaping volatiles need consideration too.

This research is only limited to particular equipment with particular settings. The path of resistance is likely to vary with different setups, but I'm certain it would follow similar trends. Isolating the bean temperature seems to be a natural progression in order to confirm the shape of the resistance curve past 60°C mark.

The coffees used are very similar in many regards, therefore I'd be cautious applying the findings to very different beans.

Nevertheless, we learned what impact the temperature has on bed resistance allowing us to maintain consistency.

If you've managed to read both parts in full - Thank you! It's not an easy read and I appreciate your effort. I would also like to thank Alchemy Coffee for allowing me to use the space, equipment and coffee for the research.

References:

1. Illy A., Viani R, (2005) Espresso Coffee: The Science Of Quality, Second Edition; Grinding p.228

2. Michael Cameron - The Resistance of Heat

3. Uman, E., Colonna-Dashwood, M., Colonna-Dashwood, L. et al. The effect of bean origin and temperature on grinding roasted coffee.Sci Rep 6, 24483 (2016). https://doi.org/10.1038/srep24483
4. Wellinger M., Smrke S., Yeretzian C., Water for Extraction – Composition, Recommendations, and Treatment, The Craft and Science Of Coffee, p. 395

Title Photo by Timo Müller on Unsplash
Mythos Photo by Yan Khanafi on Unsplash Mythos

LIPID RESISTANCE PART I: HYPOTHESIS

2020-06-16T12:10:00.001+01:00

Espresso is something you never really understand. Like almost anything in coffee, all the knowledge available merely scratches the surface. But sometimes you stumble upon an idea you think you can prove.

This article is a two-part series aimed at getting a better understanding of bed resistance. This one focuses on theory and the following on the testing.

How is it possible that coffee lipids affect resistance? That's something that I never thought about. But I have some other questions that I keep open for years. One of them is this:

Why after the whole busy morning of making the grind finer suddenly the resistance goes up and I have to make it courser?

What's even stranger is that at some point, on the busiest days, I was going finer again.

But I could never find out why that was happening. We had general ideas on how warmed-up grinder works differently. Probably due to the metal expansion under the heat.

Bean temperature

The partial understanding of the issue came from the grinding paper - The effect of bean origin and temperature on grinding roasted coffee

As the temperature changes so does your particle size distribution (PSD). Cold beans when ground result in smaller fines, but there's more of them. The opposite is true with warm beans. The reality is a bit more nuanced but in this case, we only consider a narrow range of bean temperatures.

The hopper placed above the grinding chamber and motor is likely to get hotter when it's busy. The warmer beans will grind differently. It's more about the temperature of the coffee beans than the grinder itself.

How does that apply to espresso?

Let's suppose you've dialled-in a coffee to have 35s of contact time at a given ratio and grind setting. The beans were at the room temperature. Keeping the ratio and grind setting constant you pulled more shots of the same beans. But the beans had a different temperature.

Some of them were kept in the fridge, some were microwaved before grinding.

Beans from the freezer produced 10s longer contact time. Beans from the microwave run 10s faster!

The change in temperature determines the change in PSD. There's a linear correlation of the temperature of the beans to the contact time. Since all other variables were kept constant, the contact time corresponds with the bed resistance.

Colder beans - more resistance. Hotter beans - less resistance.

That explains why you have to keep fining up the grind size to reach the desired contact time.

Until something unexplained happens and you have to go courser against all logic.

The resistance of heat

Michael Cameron published a fantastic article - The Resistance of Heat. That article shifted the perspective to heat as resistance.

Here's his explanation of the curve of resistance:

"decrease in fines and increase in size causes two things. First, this is the reason you grind fine as the grinds temperature increases. You’re losing fines, and those fines are aiding in resistance. But because they’re also increasing in size you’re left with the peculiar effect of the actual grind change itself having no added effect on resistance; you’re just lifting the mean fines volume and proportional size up — essentially “jogging on the spot”. You could be aggressive and change the grind finer, but you then jump to the middle of your resistance curve and over-shoot the mark, choking the shot. However, even if you weren’t to change the grind setting and just leave the heat of the burrs to change the grind profile, after a certain volume of coffee you’ll hit a grinds temperature of around 40°C, and your resistance will increase. Whether this behaviour in the puck is because of increased diffusion and/or dissolution, fines migration, percolation pathways, or other reasons, for now, the literature is unclear (that’s being worked on though!). Either way, it’s inevitable your resistance curve will bottom out and you’ll start grinding coarser.”

I have analysed this a lot. I was glad to see more people encounter the counterintuitive resistance increase around 40 degrees. Michael's post explains that from a perspective of volumetrics. The change in brew water retention and thus espresso yield is significant. But what about weighing every single shot? How would a gravimetric machine behave?

You always have the same yield, but a different amount of water passing through the coffee bed. The lower surface area of grounds is probably compensated with higher temperature of grounds.

But I think we should separate the temperature of beans (and their PSD) from ground coffee temperature (which we believe affects the resistance on its own).

The change in PSD makes a lot of sense. Grounds that are hotter are changing the dynamics of extraction too. The pressurised system of solid mass, gas and liquid is very complex even without considering the heat. There are certainly no linear correlations. It also seems like there are 2 different processes happening simultaneously.

Beans vs. ground coffee temperature

A while back, when I was measuring the effect of bean temperature on its resistance I noticed something very interesting. All 3 samples (beans ground at ~0, 25 and 60°C) had a similar temperature after grinding. All within 10 degrees. Which is very peculiar given that the beans varied by nearly 60 degrees! Look at this table:

The values in blue, grey, green and yellow are respectively: cooled in the freezer, room temperature, heated and cooled down, microwaved.

It was at the end of a busy day, so the grinder was quite hot - both fans engaged at full speed. The grounds were measured with an infrared thermometer.

It seems like the thermal energy within the grinding chamber has a greater impact on the temperature of the grounds than the beans. There's a lot of frictional heat generated during grinding too.

We've established both the temperature of beans, grinder and heat generated during grinding play a role in resistance. Having considered that, what exactly does the grounds temperature affect?

To paint the full picture and make the issue even more complex, there's one more thing correlated to temperature.

The post-grinding degassing plays a role. Not only Carbon Dioxide but volatiles too. It's in my experience that ground coffee left to degas offers less resistance. This is sped up by a higher temperature. To see a perspective of someone way smarter than me on this, check out Christopher Hendon's comment on that:

“letting the coffee equilibrate to the same T sounds, in principle, like a good idea and minimizing variables but actually at the T range, you were looking at *this is your biggest variable*. Chahan and his talented postdoc Samo showed conclusively that the rate of certain volatile losses occurred on the seconds (rather than 10s of seconds) time scale and the process is kinetically limited. This means at high T, cooling, vs RT sitting there, the chemical composition of the volatiles has vastly changed. Volatiles are one of the main reasons shots run at different rates - less water, solid interface, lower extractions, etc. When you grind hot you drive off more of these, and while your EY doesn't change (let's not talk about that measurement though... that's clearly problematic given the experiment I just described) your flavour profile does”

[posted: August 2019, edited for clarity]

This comment has been posted under this video, where James experiments with the temperature of beans for grinding. It confirms that the temperature of the grinder is important - in his case the cold grinder sucked in a lot of heat.

The last piece of the puzzle

About a month ago I stumbled upon a piece of research in Illy's book (Illy, 2005). I think that answers what's the unknown in Cameron's article.

The major part of coffee lipids fraction is composed of palmitic and linoleic acids and stearic and oleic in lower percentages. This blend is very viscous at room temperature, but becomes liquid above 40 degrees. At higher temperatures this liquid can easily flow through micro cracks and cover the outer surface of the particles (which can become semi-solid when cooled down). This phenomenon affects the cohesive behaviour of ground coffee when compacting, hence influencing the hydraulic resistance of the cake. Overheating on grinding may thus be responsible for erratic percolation.

The lipids affect the bed resistance. I think we're getting somewhere.

The 'erratic flow' could be also caused by clumping. As the grounds get more sticky clumps are formed more easily. The grind size and the resistance on the outlet from grinding chamber (sometimes controlled by a clump crusher) plays a major role in that as well. It makes sense, but clumping doesn't affect bed resistance unless it's extreme (like in the photo above).

I've put that to test using WDT (ref. 5) to break clumps and it follows the same resistance pattern as when palm-tapping.

What's my hypothesis?

As the temperature of the grinds increases and the lipids transform into a liquid state the resistance increases due to that transition.

Espresso flow changes somewhere around 40-50 degrees mark (it will depend on how you measure it). The resistance increases and the turbulence of flow increases (due to clumping). These two seem correlated. In this instance, they occur simultaneously.

But they are not correlated below 40 degrees. Unless your grind size is very fine (at the point of diminishing returns, usually 45s+ shots), lower resistance induces more turbulence. Think about those 18s shots at open ratios.

If you're using Mythos grinder, both fans are at full speed when you reach 45 degrees. It's designed to keep the grounds temperature below that point. Which it really struggles with in high volumes - I've seen more than 65 degrees when putting through 14kg/day. Any grinder would overheat with that. The point is, there's a good reason the Mythos tries to cap the temperature below 45 degrees. I believe plenty of testing has determined this point.

I think baristas should really focus on that point of transition into increasing resistance. Make sure the contact time stays within a reasonable range, be careful with puck prep and discard any shots that look subpar. It might be worth to adjust the brewing water temperature too.

Click here for the next part, where I explain my testing to derive the pattern of heat resistance.

References:

1. Illy A., Viani R, (2005) Espresso Coffee: The Science Of Quality, Second Edition; Grinding p.228

2. Michael Cameron - The Resistance of Heat

3. Uman, E., Colonna-Dashwood, M., Colonna-Dashwood, L. et al. The effect of bean origin and temperature on grinding roasted coffee.Sci Rep 6, 24483 (2016). https://doi.org/10.1038/srep24483

4. James Hoffman - Weird Coffee Science: Microwave Your Coffee Beans (Youtube)

5. WDT - Weiss Distribution Technique for espresso levelling and distribution (Youtube)

Title Photo by Thom Holmes on Unsplash

The sensory impact of colour and roasting time

2020-05-18T12:12:00.000+01:00

Colour and time are the most important roasting factors in creating coffee flavour. But there has been little research done on that. The opinions of the roasting community vary. Morten Münchow, Jesper Alstrup, Ida Steen and Davide Giacalone published a new paper which can change that.

It's free to access so I encourage everyone to read it:

Roasting Conditions and Coffee Flavor: A Multi-Study Empirical Investigation

In this article, I'm going to break it down and look for the practical application of findings.

The Context

It's based on sensory analysis, which makes it very practical. It's also the first scientific study of roast subphases.

The paper is very well structured and easy to comprehend. In case you're new to roasting you need to be aware of a few things to understand it.

Roast Colour is the best indicator of roast level or the degree of chemical reactions that occurred. For example, you can say a darker colour corresponds with more development. It represents a point on a scale from light brown to almost black. The most common scale is Agtron Gourmet. This scale is used in this study. For Agtron, high values (like 110) mean light colour, whereas low values (like 45) mean dark colour.

Roasting is a combination of temperature and time. Higher end-temperatures result in higher colour readings. That's because increasing the temperature speeds up many browning reactions. But every chemical reaction depends on time as well. If you give them more time, they will develop further. To achieve a balanced result you have to manipulate both variables.

Good roasters think about the whole process not just as the time from start to finish, but also specific roast phases. I wrote a separate article about them here.

This paper is analysing 2 subphases:

Time to First Crack
Development Time

Model illustrating temperature development over time for the roasting profiles and the major phases (Time to first crack, development time) varied in this research.

What was the goal of the research?

What is the impact of colour on the cup and individual attributes?
What are the impacts of overall time and specific roast phases time on the cup and individual attributes?
How do colour and time compare in their impact?

Those are incredibly practical objectives. Many roasters have had similar questions trying to understand roasting and its impact on the coffee. Certainly, I did.

Methods

The paper is based on 8 separate studies. All roasts used drum roasters, but the machines varied. Study no. 6 used a Loring S15, all other used Probat Probatino 1kg. The roasting style was a normal heat application. For simplicity, they used constant airflow and charge temperature (except for study no. 1).

The coffees used for this study were all washed: Kenyan, Ethiopian and Colombian.

The coffee was brewed in a French Press using 50g coffee to 900ml of water at 92 degrees. The brew was stirred, the crust from the top removed and finished at 3:30 min. The brewed coffee was stored in thermoses, before pouring into cupping bowls (200 ml) for evaluation at 60 degrees coffee temperature.

The coffee was evaluated through SDA - Sensory Descriptive Analysis. Meaning the panellists rated each attribute on a scale, in this case using 0-15. The attributes used:

Aroma (Roasted bread, Fruity, Cocoa, Nutty/chocolate)
Basic taste (Acidity, Bitterness, Sweetness)
Mouthfeel (Body)
Aftertaste
Other (Balance, Clean cup)

The data analysis was conducted in the statistical environment R, using a 5% significance level.

Findings

The colour has a more significant impact than roast time. The darker the coffee, the more bitterness it had, but less acidity and sweetness. Darker colour indicates more advanced chemical reactions.

Both time to first crack and Development Time have a similar impact on the cup when it comes to bitterness and acidity. But to a smaller degree than colour.

Longer Development Time correlates with lower sweetness, but the time to first crack doesn't affect it much.

When it comes to body, darker colour increased it slightly. However, either of the roasting phases had no impact on that attribute. It's important to note that the body is perceived by everyone a bit differently.

Practical application

Measuring colour and achieving consistent results is super important. It’s the most important factor in modulating flavour of the coffee. Moreover, colour is a better predictor of flavour balance than Development Time.

Development time influences taste similarly to colour, but to a smaller degree. I like to think about manipulating colour and roast phases as different tools to achieve the same goal but on a different scale.

Imagine that you want to sharpen a blunt knife. It's so blunt that it can't even cut a tomato without smashing it. For that, you need a sharpening stone of coarse grit. Something that will aggressively shape the cutting edge. It won't make it razor-sharp, but it will allow the knife to cut again. This stone would be manipulating the colour.

But the knife is not quite sharp yet. You need to use plenty of pressure to cut anything harder than a cooked carrot. That's when a finer grit stone comes into place. You won't be able to see any difference to the cutting edge with the naked eye. But on a micro-scale, it gets a hundred times thinner. Suddenly the knife cut effortlessly. That finer stone would be manipulating the Development Time.

Finally, all roasting phases have an impact on the final product. Even though modulating the Development Time yields more immediate results, time to first crack changes the taste too. Long Maillard stage increases bitterness through the creation of melanoidins. Some acids already start to decompose, leading to lower acidity if that phase is extended. Manipulating here would be the polishing touch to make the blade razor-sharp.

Roasting Conditions And Coffee Flavor is a fantastic paper. Very much needed. Scientific research will never take away the craft of figuring out how to roast the best coffee. But it can provide a solid ground for further experimentation and confirm some of our existing beliefs. As a roaster, I'm very grateful for the work and the free access. Thank you!

The curves graphic is a figure from the paper - https://www.mdpi.com/

Curve explained: Normal

2020-05-14T13:36:00.000+01:00

In the era of tracking software, there is a curve paradigm. "It's gotta be instagrammable". While a bit exaggerated, you get the point. Roasters are obsessed to make their RoRs straight.

For a very good reason, in fact.

This article is the third in the series. If you haven't read previous posts about CURVE DESIGN or ROAST PHASES, click the links now - it will help you understand this one.

This curve is the most common one. The defining trait is a declining BT RoR. It's mainstream because it's the easiest conceptually. Easy to teach, easy to spot mistakes and correct them, easy to execute.

Heat application pattern

There's not a lot of manipulation. Heat is absorbed gradually - as the beans rise in temperature, gas is lowered. Thus, the roast is progressively slower and slower. That results in steadily declining RoR.

This roast has been tracked, but I didn't look at Cropster while roasting. I have roasted it in an "old-school" way, based on smell and colour. The charge was at the standard temperature for that batch size. I used a soak, after about 2min the gas was increased - to the highest setting during this roast.

I don't change it until coffee turns yellow. On the colour change, I reduce the gas by half. The coffee has gained some heat already (reaching about 150 degrees) and it has less moisture, so it doesn't need as much energy.

About 40 seconds before the first crack, I reduce the gas in half again. That's the setting the coffee went through the first crack. Establishing a correct FC gas setting is crucial in this style of roasting.

Because it was a very light roast I dropped the batch 40s after the first crack. There was no need for another gas reduction.

Some coffees are not going to follow exactly the same pattern. Particularly around the first crack. The heat application will derive from the above. For example, you might reduce the gas a little bit earlier than a colour change. Or reduce it not by 50%, but by 40% or 60%. And most likely have another 5-15 gas changes during the Maillard stage, to make it more gradual.

From top to bottom (right side): ET, BT, BT RoR, ET RoR. You can see where the gas was reduced looking at dips in ET RoR.

Interpretation

The curve is smooth as a result of gas application based on physical and chemical changes of the bean. The initial high setting allows the heat to penetrate the beans. Especially in the very beginning of the drying phase.

Before beans reach 100 degrees, moisture inside acts as a carrier of the energy. After that, it takes much more energy to heat the water as it turns into steam and create internal pressure. That's why the RoR starts decreasing after this point.

As the moisture evaporates and the beans rise in temperature it requires less and less energy to keep them going. Thus from colour change onwards, gas settings steadily decrease.

That allows for the heat to penetrate inside, without overroasting the outside of the beans.

This roasting strategy is not the only one, but certainly the easiest. Usually, my first roast of any coffee would use it. There's plenty you can learn about the coffee this way.

But it has its limitations.

Crash and flick (baked and roasty)

The crashes don't get bigger than this. There was little sweetness, acidity or flavour in this coffee.

One of the biggest challenges is avoiding baked flavours. Almost everyone defines baking differently, but it's commonly agreed that BT RoR crash after the FC, could cause it. With this RoR shape, you may find little room for your airflow and gas settings around the FC to avoid crashing.

More developed roasts will be prone to RoR flicking, causing unnecessary roasty flavours.

That's a tremendous flick, after a big crash too. This poor Kenya was absolutely butchered - unfortunately, this roasting style has these traps set up for you with these kinds of coffee.

Modulation

If you're keen on adjusting phases of the roast, you have little wiggle room. While it's easy to adjust the drying phase it gets more challenging further down.

The Development Time (DT) needs a good percentage for even development. Aiming for a specific RoR value could help, but it changes the dynamic of the FC.

It's very tricky with the Maillard phase. Changing its length without affecting drying and DT quickly leads to thinking about the angle of the RoR curve. But that is correlated with the length. What if you don't want to change it?

It is possible, but it's very hard.

The beautiful curve

Another risk is relying on visual data (shape of the curve) more than the taste of the coffee. I've fallen in that trap myself.

The curve is only one of the tools to help you. You're roasting coffee, not drawing lines. The consumer doesn't care how pretty the curve was, if it doesn't taste good.

The normal curve is great! I roast the majority of my coffees using a form of this curve. It gives you great insight into how the coffee behaves when roasting. Like any other, it has its challenges, but there are solid strategies to mitigate them.

The next article in the series:

The previous article in the series: Roast Phases Explained

References for the series: Roasting Series References

Peak Water Jug Review

2020-05-09T12:09:00.000+01:00

The magnificent Peak Water Jug. Aiming to revolutionise the quality of water for home users. Starting as a Kickstarter project in 2018 it's gotten a lot of attention from the industry. Does it live up to the expectations?

I backed the Kickstarter on the 9th of April 2018 with an Early Bird option as backer #181. I received the jug on the 8th of April 2020. In April 2018 backers received an email that at that point the project has already been running for 2 years. That shows how long it takes to create a completely new product and put it on the market. Hats off for that!

During the process, backers were regularly informed about the progress, changes and setbacks. It's been nearly 30 emails. Through them, you can learn a lot about the complexity of R&D. It's been good communication.

First impression and setting

The plastic is smooth and pleasant to touch. Installation of the disc filter is easy and well explained in the user guide. Like every other filter, it has to be flushed with 2.4l of water. However, it's not consistent until after 5l has gone through the filter (setting 4).

Less than perfect fit.

The testing strips attached work well. However, comparing them to titration, the reading is more accurate if you wait for more than recommended 10s. If not, the default setting for my tap water would be 3, whereas it should be closer to 3.6 for best results.

Performance

How does it perform? I'm pleased to say it's terrific. It can compete with expensive commercial filtration systems.

In fact, it can outperform some filters because it doesn't lower the pH even on very high setting. That's especially great if you use an espresso machine. It helps prevent corrosion and extract well - I wrote a whole article about that here.

The biggest feature of this jug is a step-less adjustment. It can produce water in an amazing range of hardness. You can dial in your water to the roast, type of drink or preference. If like me, only drink filtered water or try to get the most of teas and herbal infusions, it's perfect.

No more building your own water, when you get coffee from the US, Asia or Australia before it will taste good. As a roaster, it allows me to QC my water in a wider range of water specifications. As well as experiment with impacts of water on perceived development. It's my favourite thing about the Peak.

Please see the table below for numbers (based off my London tap water):

PPM measured with a conductivity meter and carbonate hardness with BWT titration kit (german hardness degrees).

My preferred setting brews similarly to Volvic but has more flavour clarity.

When drinking the water from Peak I could taste a hint of plastic. Also, when you open it, you can smell it. I feel like it got more intense recently, although I could have not paid much attention to it initially.

The filter

As for a gravity-based system, the bypass is very reliable. It's not linear, especially between 4 and 5. Given that it's step-less you can pretty much hit any number you want, but I usually blend for that purpose.

Aside from a bigger range than most commercial filters, it's very consistent. When the performance drops, it happens quickly, prompting you to change the filter. It's not affected by the environment temperature (like some remineralisation cartridges do).

This review wouldn't be honest if I didn't mention my faulty filter. I reckon it was mishandled after production and damaged. It worked fine quality-wise, but a tiny bit of resin escaped the disc. Because that's already in contact with the water, I was not bothered about the quality of water.

However, it's been annoying to get rid of them. Usually, I'd waste 10% of filtered water (the granules sunk to the bottom).

Resin granules

The issue was promptly resolved by the team and I got a new filter as soon as possible.

Overall

It’s probably the best product on the market in that category. It's fantastic for brewing and drinking water, especially if you have hard tap water. The design is modern and would fit between Acaia scales and Fellow kettle. I don't care much about the perfect fit of the parts, even though it could be improved.

It's a shame I was so unlucky with the filter, but that's the nature of manufacturing. As with any new product, it's difficult to test it for any circumstance the home user might come across. I bet the team is hard at work gathering feedback from the first user group to improve the next iterations.

At the end of the day, I was expecting a simple plastic jug doing a better job than mainstream water filters. I got everything that was promised in the Kickstarter campaign. All my expectations were actually exceeded, except for the waiting time.

Good job Maxwell and the Peak Water team!

Roast phases explained

2020-05-02T12:03:00.000+01:00

Good roaster understands their craft beyond the curve and approaches it based on bean changes. Following the reference is simple, but roasting is more complex than that. There's a lot to be aware of.
The beans undergo a radical transformation. But the change is gradual. You can think of it in 3 steps. Drying phase, Maillard phase and Development Time. Let's see them on the curve:

Tracking software allows you to mark phase changes.

This article refers to concepts explained in the previous post about roast curves. If you haven't read it yet - CLICK HERE

The drying phase

During this phase, there are no chemical reactions happening. The most significant process is the loss of moisture. Keep in mind though - the coffee loses water through the whole duration of the roast.

The phase starts when you charge green coffee into the roaster. Charge temperature is an important indicator here - a control of thermal energy at the start is paramount to consistency.

Green coffee, before roasting.

Your heat application starts immediately as well. You can add gas right off or choose to soak (letting the coffee absorb existing heat).

If you look at the bean temperature curve, the most exciting part of it is the Turning Point (TP). This is the first point the curve indicates the speed of the roast compared to the reference

During drying, there aren't many aromas released. But towards the end of it, you can pick up grassy and green notes.

This phase is very important in profiling. It's establishing roast momentum, building up seed pressure and setting up an inner bean development. Some theories and roast curves are based on that. We’re gonna revisit these in future posts.

The Colour Change - coffee turns yellow.

This stage ends when the coffee goes through the Colour Change (CC). It's subjective when you mark it - but it's vital to be consistent. Personally, I call it when there's no green visible anymore.

The Maillard phase

Named after one of the chemical reactions, it's the phase when most of the transformation happens. The colour changes from yellow to brown. Maillard reaction, Strecker degradation and caramelisation start creating flavour. These can be also called 'browning reactions'

Usually, during this phase, the operator lowers the gas to ensure sufficient development. This phase is for complexity and body. That is due to melanoidins - compounds responsible for viscosity and "brown" flavours - think bread or porter beer.

If you wouldn't spend enough time in this phase the coffee would lack body and complexity.

During the roast aroma will be shifting corresponding to the colour. From green (grass) to yellow (straw, malt) into brown (bread, caramel).

The Development Time

This phase starts with the First Crack (FC) and ends when you drop the batch. The crack is caused by the build-up of pressure, due to water vapour trapped inside the bean.

This causes a rapid moisture release which makes the control of the roast challenging. A lack of skill in managing that is associated with the baking defect. Hence all roasters are extra careful around the First Crack.

Coffee after First Crack.

In Development Time (DT) evaporation and all reactions from Maillard stage are continuing.

The new reaction is pyrolysis. The degradation of organic compounds. A reasonable level of it increases the complexity, but the line is thin. Too much pyrolysis causes burnt, bitter flavours associated with overdevelopment (roastiness).

Most importantly, organic acids are degraded. That is crucial for the control of balance and flavour of the coffee. The longer the DT, the less acidity in the cup. But if you wish to have a complex, multi-dimensional acidity you need to decompose them to a degree.

The art is to balance them all to your preference.

If you go far enough in DT you'll experience the Second Crack. This one is caused by the build-up of carbon dioxide. Coffee gets dark brown, oils bleed to the surface, roasty flavour is dominant. Most of intrinsic flavour characteristics and acidity are lost.

The length of your development time is very likely to be affected by your water quality. Think longer for softer water, but it's complex enough to have a whole course on that.

Aromas during this phase are incredibly varied. It starts off with vinegar (product of caramelisation) - you can use it to mark the FC if you can't hear it. After that, it shifts from floral to fresh fruit to candy, then molasses and dark chocolate. Nearing the second crack you'll experience dry distillates like wood, rubber and carbon.

How do they come together?

It's almost impossible to talk about phases without modulation. Altering their duration shifts flavour and mouthfeel. For example, by extending the Maillard phase you can increase body without roasting darker. Or shift from lime to pink grapefruit by extending the DT. Rob Hoos wrote a great book about it.

An example of poor phase lengths matching.

Once a certain process starts happening, it will continue until the end. Building a lot of pressure in the bean during drying can make controlling the FC difficult. Good inner bean development strategies early on allow for shorter Development Time. It's all connected.

Every single stage is important for solubility and flavour creation. Along matching the curve, getting the same phase lengths is key to consistency. Understanding each step will help you achieve that!

The next article in the series: Curve Explained: Normal

The previous article in the series: Roasting Curve Design

References for the series: Roasting Series References

Photos:
Title - Me in 2018 smelling for First Crack
Curve - light roast El Salvador on P12
Green, Yellow and Brown - Dan Bollinger, CC BY-SA 3.0
Modulation chart - trying to roast Colombia using El Salvador profile

Roasting curve design

2020-04-22T12:04:00.000+01:00

The biggest innovation in roasting was a roast tracking software. A continuous real-time data collection and roast curves make it much easier.

What is a curve?

A curve is an object similar to a line which does not have to be straight. Intuitively, a curve may be thought as the trace left by a moving point - Wikipedia

The roasting curve is a function of time and temperature. You can draw one yourself if you have a stopwatch and a temperature readout. In fact, before tracking software, that's how it was done. But it was challenging to keep that data accurate, therefore consistency was elusive.

But do the roasting curves make it easier to understand the process?

Yes and no.

The chances are if you're not a roaster, you're not going to understand this:

When analysing the roast curves, you could be looking at 4 or more, plus additional data like gas changes. It's hard to understand it if you don't know what to look for. In fact, even experienced roasters might not know what to look for.

Let me break down each curve and what it represents.

Bean temperature

Arguably the most important curve is a Bean Temperature curve (BT). It tracks the temperature of beans during the roast. If you were to have only one probe to measure temperature it would be this one. It forms a "V" shape, like such:

On the Y-axis (vertical) you have a temperature scale. On the X-axis (horizontal) you have Time.

That "V" seems counterintuitive. Putting room temperature green beans into hot roaster is going to make them hotter immediately, right?
But before that, the bean probe is measuring air inside, which at this point could be around 200 degrees.

After charging, the probe is suddenly covered in cold coffee beans. It takes a minute or two for the probe to reach equilibrium with coffee. Since then you can trust the probe as the rough approximation of the bean temperature.

Rate of rise

The most exciting functionality of roasting software is a Rate of Rise (RoR).
RoR is a change of temperature over a period of time. For example, let's take the BT curve from above and calculate RoR using 60s interval:
- at 5min, the temperature is 160 (I'm rounding to 10)
- at 6 min, the temperature is 170

Over the minute, the temperature has changed by 10 degrees. So, your RoR at 6 min is 10.

You can calculate RoR based on any interval you want, frequently roasters choose 30s or 15s, as it gives you a more responsive curve that 60s.

You'll notice, on the right Y-axis is a scale for RoR, here using a 15s interval.

BT RoR shows you the speed at which your roast is progressing at any given point in time. Thus you can notice if your roast is on track before BT curve would indicate that.

Majority of roasters spend most curve-analysis-time on this one. It's a good indicator of a heat application - the addition of heat in particular ways at particular times.
There are many theories created around it, each one deserves a separate article (coming soon!).

Exhaust temperature

It tracks the temperature of the air leaving roaster during the roast. Typically it increases until before the first crack. Why measure it?

ET and BT are using the same Temperature scale. You can notice a sharp increase around 2 min mark - that was the first gas increase.

It gives you an understanding of the flow of heat through your roaster. That's important because BT probe shows you temperature only in one spot. But the roast depends on the thermal energy of the entire machine. If you were to charge the drum with BT: 200 and ET: 180, when usually you use BT: 200 and ET: 210 you risk underdeveloped roast. Without ET probe you can only guess.

Besides, the ET curve provides more reference points and indicators. For example, in some styles of roasting, ET RoR could be used to mark the first crack.

ET RoR peaks at 42.

Why are the curves so important?

Replicating roasts

The biggest challenge in roasting is consistency. Making 2 roasts that are identical takes a lot of skill.

Roasting software allows you to save previously executed roasts with all details (curves, gas changes, airflow etc.). Using a reference profile for every batch is the standard.

Tracking curves is the easiest method of replicating roasts. Even if some of your parameters are a bit off or miss a gas change, you still have a good chance of matching the colour and flavour of the coffee. As long as your curves are close enough to the reference.

The next post in the series: Roast Phases Explained

References for the series: Roasting Series References

Create your coffee network

2020-04-13T13:15:00.000+01:00

The coffee industry has an amazing community. There are lots of driven, curious, passionate people that propel it forward. It's certainly one of the reasons I love it so much.

But it's not just about good friends and having fun. Professional network is an incredible tool to develop your career. Don't underestimate it!

When you're considering getting a new job, your connections serve an instrumental role. One person could share a job advert. Another has worked at the company and can give you some insight. Your mentor could help you prepare for the interview. An ex-colleague has a similar role and can share their expertise. Previous boss might become your client etc.

There are many levels on which other people contribute to your success. You never know when you'll have to reach out for resources you don't have yourself.

Best practice

Creating and maintaining your network is a set of behaviours (or rules if you prefer). Everyone can learn and adjust them to their personal style. Let me point out 4 major ones:

1. It's not about hanging out - adding someone to your network doesn't mean going for a pint. Especially if you've connected on a coffee event, you don't need to go to the 'afterparty'. After exchanging contacts it's about catching up regularly and creating value from there. Getting drunk together is not professional.

But what if you haven't seen someone for ages, they're in town for a festival and you want to catch up with old friends? Go for it!

Your network supports 3 areas. Skills - when you ask a fellow roaster if they charge naturals at a lower temperature. Career - when you ask a more experienced person if going into management is the right move for you. Social - when you hang out with your old colleague and chat about coffee, life, and other common interests. All areas are valuable on their own and intertwine with each other.

2. Volume and diversity - do not discriminate. Don't ask yourself how that person would be useful in your network. We tend to connect with people in our proximity or that are similar to us, even within our own companies. If you never see the engineering team, change it. Make the point of knowing at least one person from every department, branch or location - even if it's just a virtual connection.

Don't limit yourself to an internal network only. Get to know your suppliers and not just your contact person. You're buying coffee from a roaster but only ever meet the sales team? Send an email directly to the roastery, maybe ask if you can visit the space, come over to their stand on an event (if possible).

Know your 'competitors'. At the end of the day, you have the same goals, even if you vary in the approach. It's ok to show up at their event, taste and discuss coffees together, maybe even offer help. But it's not ok to promote your company or product there. Invite them to your events too!

Research shows, most benefits come from weak ties - acquaintances and friends of friends, rather than close friends. That's the power of diversity.

3. Be a giver - There's a ton of research about how it pays off to have a reputation of a giver. People want to reciprocate to givers (unless they're selfish takers).

Offer help, share your knowledge, be generous. It could mean as little as lending your spare scales (you don't need that Brewers Cup setup daily, do you?), giving away a bag of coffee or mentoring someone. You don't need to be an expert to mentor, even as a trainee with 3 months of experience on the job, you have plenty to offer to someone hired last week.

Competition is another great way to meet new people. You will see people from different companies, regions, positions. Between competitors, judges, organisers, and volunteers you'll see baristas, roasters, salesmen, technicians, green buyers, manufacturers, senior managers and even people from the commercial sector - all in one place.
But think about how you can contribute. Do you have a day off and can help clean the tables or measure TDS? Have you considered judging? Or getting involved in your national SCA chapter?

Be a giver, add value and show support.

Obviously, don't burn bridges. Even if the other side did. Be kind and positive about people you used to work with. Don't broadcast your bruised ego within your network, it's not worth it even if you're right.

4. Keep in touch - take a contact detail and connect every 3 months or so. One of the reasons to go to coffee events - it's nice to do it in person. But email, Instagram or text message are perfectly fine too.

Offer value - share a good article, insight or your work. Be genuinely interested in them. Ask relevant questions. If they moved, got a promotion/ changed jobs, got married you should be aware of it. If you're super savvy you can add these details in the notes of the contact - it would look bad to forget them when you're catching up 3 months later.

How to start?

If you're not on LinkedIn yet - use your free time to set it up. Don't expect to be offered a job there (although that happens).
It's a great tool to see what people in your network are doing - for example, someone changed jobs or got promoted. You can look up people in the position you want and see how they got there - or even send them a message!

It's always a good idea to grow your network. But not many people are naturally extroverted. Meeting new people can be terrifying. Though usually, within the industry, there's plenty you already have in common. When you're on a public cupping ask the person next to you what they think about the coffees.

Most of the people in the industry are or have started as baristas. That's the best prep for networking. Being nice and helpful by default is the best approach you can take.

There was an interesting research done on networking. They've put a bunch of professionals from the same industry together in the bar. The objective was to let them mingle and analyse social interactions. Every person in the room was monitored, even the bar staff. It turned out the person with the best interactions was a bartender.

That's good news for all of us coming from hospitality.

Coffee community is fantastic and you're an active part of it. You can have a positive impact on others and benefits yourself as well.

Developing a strong network should be part of your career plan. It's very likely it will have a direct impact on your success on the job or getting a new one. Let alone the satisfaction you get from helping others.

Stay strong and keep in touch!

Sources and inspirations:
1. Grant A., (2013), Give And Take
2. Ingram P., Morris M.W., (2007), Do People Mix at Mixers? Structure, Homophily, and the "Life of the Party"
3. Burkus D., (2018), Go Ahead, Skip That Networking Event, Harvard Business Review
4. Manager Tools - Networking Podcasts (check these out!)

Title photo - Photo by Alina Grubnyak on Unsplash
Second photo - Kaffeine Throwdown, it wouldn't be so much fun without friends
Third photo - Brewers Cup 2016, SQM
Last photo - Brazilian cupping at Kamba Coffee

How to grow being off work

2020-04-08T11:14:00.001+01:00

If you're reading this, the chances are you have some free time. Whether you are furloughed, in between jobs or work reduced hours you could use this time to learn a new skill or plan your career. I also recommend staying in touch with the industry and catch up with recent developments.

Obviously, if you have any health issues or there are people you need to take care of - focus on that. Be aware of your mental health too. Maybe you've been overworked or haven't had any holiday in a while. Take care of yourself first, avoid burnout and make yourself ready for progress.

It's certainly a good idea to have something to look forward to. The benefits of goals aren't in achieving them, it’s that they give us direction and meaning.

While you're not on the job, you're not gaining any experience. You wouldn't want to stay behind those who use this time productively, especially that it appears the job market will get more competitive soon.

Practicing brewing and playing with your equipment are a great way to keep in touch with coffee. Personally, I cranked up many hours doing at home cuppings, experimenting and refracting hundreds of brews. But nothing has a greater impact than a solid plan to reach your aspirations.

Career plan

Below I will outline the full-on program you can take, but you can cherry-pick particular steps if you like. Every little helps, but if you've lost your job or are looking for a promotion, you shouldn't leave it up to chance. Do as much as you can!

There are lots of links in the text - click them!

Analyse your skills
A SWOT analysis might be a bit of an overkill, but it's worth the effort if you need a solid Personal Development Plan. A simpler option is to take a piece of paper and write down all your skills (as well as their level) and accomplishments. Pay attention to both coffee skills and non-coffee skills.

Examples:

Coffee skills:
1. Latte art (7 stack tulip, heart, rosetta, swan, phoenix mastered)
2. Sensory skills (SCA Sensory Intermediate)
3. Dial-in (getting 3.0 balance score within 15 min using less than 250g of coffee)
4. Basic maintenance (cleaning grinders, changing seals)
5. Roasting

Non-coffee skills:
1. Management (feedback, coaching, delegation, hiring, team-building)
2. Excel (ECDL Advanced)
3. Public speaking (audiences up to 50 people, using props and slides, demonstration)
4. Video-making (shooting, editing)
5. Social media marketing (content marketing, paid campaigns)

Add details, equipment/software you've used, certifications, courses, finished projects, quantify what you can.

What's your ambition or potential?
Now take a second piece of paper (or use the other side) and write down the skills that you need to be where you want. Use these questions to guide you:
What do you enjoy doing? What do you want to get better at? What do you think you can become good at? Is there a job you want to do?

It's good to reach out to friends, colleagues or even your boss to find the answers. Figuring out these things takes time, let it dwell for some time if you don't arrive at the answer immediately.

Skill gap
After you have both lists ready, you can identify the skill gap. Let me show you the way I would do it.

Let's assume you a head barista looking to become a wholesale trainer.

First off, get the list of skills that you need. It's a good idea to find a job advert and take it from there.

Wholesale trainer skills:
Be able to demonstrate an in-depth knowledge of extraction theory principles and milk preparation
Be able to create a written curriculum
Have excellent presentation skills
Be organised and responsible for time management
Have a good working knowledge of equipment, with some maintenance skills
Great interpersonal skills
If you have SCA qualifications this is desirable, but not essential
Good written and spoken English skills
Must have a full UK driving licence

Put this list next to your current skillset.

Current skillset:
Good understanding of extraction theory
Creating rota for the shop
Grinders cleaning
Good customer service
SCA Barista Intermediate
Copywriting
Creating espresso and batch brew recipes
Use of refractometer

And compare. Make yourself feel good by listing out the overlapping ones. Ask yourself if you need to further develop any of these to increase your chances.

Overlapping skills:
Extraction/ milk knowledge
Organisation and time management (rota)
Interpersonal skills (customer service)
English skills
SCA skills - it's worth getting Professional level and AST qualification in this example

The most important part though is the missing link. That's where you will put most of your efforts.

Skill gap:
Creating curriculum - writing skills are there, but it's more about the structure, that could be learned quickly through google search and a bit of practice on imaginary courses
Presentation skills - being familiar with being on display and talking to people helps, but a couple of Toastmasters sessions, getting familiar with the use of slideshows, props and demonstration will create the backbone of this role
Driving license - sign up for the course asap
Technical skills - knowing well how espresso machine works might help you answer a tricky question, make sure you know all basic maintenance too - YouTube is a good resource, but ask the company's engineer too

Anything else worth adding?

The more 'coffee knowledge' you have, the easier it is to create training outlines and answer trainee's questions. Read coffee books or blogs, sign up for an online course, compete (if possible).

You will probably write much more professional emails and spend time in meetings. Learning basic business etiquette will go a long way.

Study different ways of learning. People engage and react in different ways. Get familiar with the Honey & Mumford test and learning styles.

Oh, and don't forget about projectors/ laptops. Technical issues can ruin the session. Figure out how to quickly terminate problems, but also be prepared to roll without the slides.

The list is not exhaustive, but I hope it gives you a clear picture of how to tackle the model. To get the job you have to be the best candidate, it's not just about ticking the boxes. Even if you don't plan to apply for anything soon, it's a good idea to polish your cv - keep it one page, simple and black&white. I'd recommend making a sample cover letter too - include relevant accomplishments. You will be tweaking both later for specific job posting, but it will be 10min, not an hour.

Resources
Having established the skill gap, it's now time to close it. Some of the skills will require you to be on the job, at least in a trainee position. But there's plenty you can do at home, particularly from the 'non-coffee' list.

1. Coffee books - a separate post about coffee books is long overdue, I promise to change that soon. In the meantime look up the SCA store for reference. Ask friends, colleagues, your boss if they could lend you anything. Many companies have some resources hidden in the training space, office, storage room - ask for them!

2. Coffee blogs - my 3 favourite are written by Christopher Feran, Michael Cameron, Jonathan Gagné, but check out my new section Recommended Resources for specific articles. Many roasting or importing companies have a blog section, follow them.

3. Other coffee media: podcasts (TamperTantrum, Boss Barista, Filter Stories, Filtered Thoughts), YouTube (Re:co, Wrecking Ball, DRWakefield), Instagram (Rao, Hoos, SKLeng)

4. Learning platforms: Skillshare, Coursera, Future Learn, Duolingo, TED and many more, you never know what you stumble upon if you google things - I have spent hours on aquarium forums learning about water.

5. Career Advice - Career Tools - absolutely fantastic interviewing series, Manager Tools (for managers or wanna-be-managers) - I've never heard of a good management training in a coffee company, you don't need theory, but knowing effective models and behaviours will help a lot even if you're a head barista.

6. Learning how to learn (know your learning style), managing and improving your communication, emotional intelligence and mental health will be the best foundation to be a successful professional. Do not overlook it at the cost of hard coffee skills and knowledge!

Being off work is the best time to make yourself a more valuable professional. Doing that when you're not forced to, gives you the comfort to grow at your own pace. But having a bit of structure to it streamlines the process. It's also a fantastic time to get in touch with people from your network, I'm sure they'll be happy you did.

Title photo - brewing at home, notice I got a refractometer before upgrading my grinder :) #poorchoices
Writing - Photo by Helloquence on Unsplash
Bridge - Photo by Alex Azabache on Unsplash
Orange VST - learning how to dial in a cupping at a friend's house
Cupping - the first one I did (2015), I'm pretty sure it was Tap Coffee, Pact and Starbucks

What changes the tactile of espresso?

2020-03-14T10:54:00.000+00:00

There's little research on tactile in coffee. It's been a bit neglected compared to attributes like a flavour or taste. It's easy to predict how the balance will shift when changing your recipe. However, it's not that simple with tactile.

Throughout this article, I will be using names of attributes from WBC sensory scoresheet. I separate tactile into weight, texture and aftertaste. You may notice I have a preference for a higher flavour clarity and better taste balance over big weight and texture. I don't mean one is better than the other, I just want to make my bias explicit before you read further.
Also, I decided to simplify some things in an attempt to increase clarity.

From the most basic perspective, we tend to associate the tactile sensations with strength. But there are more variables at play with texture and aftertaste. Can we even isolate variables in the perception of weight? It's interconnected, but let's try to break it down a bit.

Weight and strength

A perceived weight of espresso is directly correlated with its strength - TDS. The higher the TDS, the bigger body. Most of the time. The weight can be adjusted with the ratio of coffee to brewing water. Lower TDS, found in more open ratios, makes it easier to recognise the flavour.

More open ratios extract more, have more flavour clarity and have a lower weight. The main problem with a high TDS espresso is its ability to hide imperfections - roast defects, lower-quality green, poor dial-in etc. While sometimes you may want to do that, it's not fair if you're quality-focused and your choices regarding green coffee, roast and extraction level are meant to represent that.

Why do we stick to 1:2 ratio?

We are as an industry able to pull high extractions (above 22%) with a 1:2 ratio. The concept of roasting coffee to high solubility is not just about darkness anymore. Grinders and espresso machines (Decent in particular) are better, just like our ability to calibrate and set them. And we have revisited puck prep and started developing tools to improve it. The boundaries are pushed and that's fantastic. But that's still difficult to do. Probably you're not able to do it in a busy cafe, over the course of the day, across the whole team.

So more open ratios are better, right?

They are easier to work with. They give you a chance of extracting more. And it's not a marginal gain.

Flavour clarity will increase as well. You citrus is more like pink grapefruit, your floral is actually lavender - pretty cool! With that, any imperfections will become present. And that's the 'negative' of high flavour clarity.

For example, maybe suddenly you taste roast. You think you've extracted 'too much', but in reality, someone was not careful in quality control.

What do I mean by that?

Unfortunately, some roasters approach espresso roast as 'it should be balanced at 1:2 ratio' - which makes their job very difficult because reducing acidity to a balanced level at this ratio usually drives profiles into overroasted range. Fundamentally that ratio sets you up for a very low extraction.

Open ratios, channelling and aftertaste

Another challenge of open ratios is astringency. Drying aftertaste is not desirable, even if you like it (I'd recommend red wine and black tea instead). Astringency comes from tannins - which are difficult to extract. However, if there's a substantial amount of turbulent flow due to what we call channelling, tannins extract.

What is channelling then?

In short, it's the formation of locally increased flow due to poor puck prep and pressure/ flow related issues.

More open ratios will highlight astringency. Primarily because of the higher clarity - there's nothing to hide it.

But also because channels and their effect on aftertaste are not linear. They don't cause dryness immediately. You could pull a 14s shot that looks awful and perceive no astringency, even though you could swear there's a ton of channelling happening. If you could stop the shot when channel appears, you'd have little astringency. The concept is not very different from cutting your hand brew short when it chokes.

There's a lot of benefit from more open ratios. Including more flavour clarity and generally higher extractions. If you're like me you will enjoy lower weight too.

But that's enough for ratio. What else changes mouthfeel?

The dose and contact time

Contact time as a variable in the tactile seems very easy to explain. As you grind finer, you increase surface area and resistance - water has more particles immediately available for erosion and more time to extract. The more you extract, the bigger the body.

Except I'm not sure if having more time increases extraction in espresso. Espresso extraction is almost 100% surface erosion. It happens almost immediately when water comes in contact with particle. Theoretically, it's a waste of time to slow it down with increased resistance. It would have to be an uneven flow that would need more time to extract fully.
Is it the grind size being too fine causing that unevenness? Probably.

Recently we have people all over the world pulling 15s espressos and getting pretty high extractions. Try it yourself! The balance and flavour are there, but weight is very low.

It seems like there's something else at play that has little to do with a level of extraction. It's not about what gets dissolved - it's about what gets into the cup undissolved. Let's have a look at it from the other perspective - dose.

How does the dose affect the body?
(my untested theories)

When you have a high dose you have theoretically more surface area available for erosion. Now, there are plenty of reasons why high dose (say 20g) is not efficient for extraction (I wrote a little novel about it here). But let's assume it's not a factor for a moment. Even if erosion is not efficient (uneven extraction) it would extract something.

Does something from the very beginning of extraction cause high weight? I'm guessing it has something to do with a molecule size and molecular weight - like in homogenised vs. unhomogenised milk (we perceive bigger globules as heavier).

How about lipids?

Fat is not very well soluble in water. But with high pressure, temperature and turbulent environment it would appear some would end up in the espresso. Some people even separate it and taste it - apparently, it's not very good.

It's safe to assume that you would get more lipids from a higher dose. In cooking, fat products increase weight. So it would make perfect sense that more lipids means more weight in espresso too (maybe that's why lower dose espresso tastes the way it does?).

And let's not forget about the baskets! They certainly let a lot of colloids flow through their holes. Colloids are well known to increase perceived weight. You get more of them from a bigger dose, especially if your basket manufacturer changes total open area (amount and diameter of the holes) to compensate for resistance change. One might think that also lets more lipids in. I have not considered the effects of fines migration on that.

Going back to contact time. I could theorise that with lower contact time you get less lipids into the cup. Probably less colloids too - after all, they have to squeeze through tiny holes in a limited amount of time.

If that was the case, the length of extraction would have less effect on weight than grind size and its implications. It's proven that you don't need the 30s to extract 20% and above. But maybe you need that contact time to achieve the weight of espresso as we know it?

What do you think? Do you agree? Let me know!

Resources and inspirations (links):

Coffee Meditation

2019-01-20T15:21:00.003+00:00

This morning I was drinking coffee. It's nothing unusual. But this time was different.

As I placed the cup of coffee in front of me, all my attention focused on it. Nothing else existed. I was completely absorbed.

Drinking that coffee I paid undivided attention to its attributes. Acidity, sweetness, bitterness and overall balance. I felt the weight of the liquid on my tongue. Pushed it through my teeth to feel its resistance. I pondered the flavours. After the last sip, I immersed myself in the sensations of the aftertaste and how long it lasted.

You might think that's what I do with my coffee every day. And to some degree that's correct. As a coffee professional, I tend to analyse what I drink a lot. Usually I'm very judgemental. If I notice high acidity, I would think if it's positive or negative. Is it balanced?

When meditating you take things as they come. In a nonjudgemental way. It's all about awareness of current sensations.

It's not easy for me to drink coffee without deeper consideration of its quality. Sometimes I drink coffee mindlessly, but these moment are rare and I struggle to avoid them.

However, I enjoyed that experience a lot. I know very well what flavours or balance this coffee had. But I did not evaluate it. I'm not able to say if that coffee was good or very good or exceptional. I didn't pay attention to that. I didn't judge. But the pleasure I experienced it was definitely extraordinary.

Bringing enjoyment to everyday activities is very rewarding. Through exploration of coffee I raised my expectations very high. There was a moment I thought I'm not going to enjoy my coffee anymore. How frightening to realise that what got me into coffee turned against me!

I believe nonjudgemental awareness in the key to enjoyment. I won't let my coffee knowledge ruin my experience. I will drink my coffee without thinking if it could've been roasted or brewed better. I will not score it against 90-plus competition coffees I had tasted. I will just take it and enjoy as it is. Without judgement.

Photo by NordWood Themes on Unsplash

I want to quit coffee

2018-10-13T11:52:00.000+01:00

Coffee is hard. It doesn't pay big money. It's not considered to be a prestigious career choice. And the path for professional development is not clear.

But more importantly, this industry is pretty hard on mental health. Particularly at a barista-level.

Long hours, shift based work, constant customer facing, lots of emotional labour and low pay. Time after time, baristas get home exhausted. Too tired to cook a proper meal - ending up with a cheap takeaway or ready-made food. Too tired to engage in social activities - leading to a sense of loneliness. While not having energy to even look for ways to change the situation.

Have you experienced prolonged stress at work?
Have you lost your passion?
Have you had a breakdown?
Did you want to quit coffee?

If you said yes to any of these, read on.

We identify ourselves as coffee professionals. We have passion and values. We choose to work in coffee.

With scarce exceptions most people start at an entry-level - being a barista or barback. Hospitality is hard - humbling, stressful and draining - no matter how good you are. Coffee businesses operate on small margins and that doesn't help either.

Talor Browne has conducted a survey about mental health in coffee industry. The results are terrifying. 66% experienced work related anxiety, 40% suffered from depression, 34% from insomnia. Those are not marginal numbers. The scale of the problem is big. I highly encourage you to read through the results here and watch Talor's presentation here.

Emotional labour

The big part of a service industry is emotional labour. Which I define as regulating emotions dealing with customers, colleagues or your boss. It's tough to provide a good service when you have a bad day. Professional feedback gives place to a frustration-driven criticism when you're tired.

Basic care and empathy for customers are more draining than a deep emotional labour. It's the unexpectedness and shallowness that make it harder and less meaningful. Such emotional labour leads to higher stress levels, which can result in an aggressive behaviour (Szczygiel, 2009).

Poor career prospects

The perspectives for baristas are terrifying. Many think coffee is a dead-end job. After two years there's very little more to learn. And unless you're extremely extroverted you will struggle to put the same amount of passion you did at the start. Most baristas will quit coffee. Progression is very limited. Few managing positions, even fewer in wholesale, training or roasting. Let alone green coffee, product development or research jobs.

The most difficult is the first step - leaving the bar. That's a mental barrier and an important validation point.

But many will never make it to that point. So many young, talented and hard-working baristas will abandon their passion. They will quit coffee.

Why is that?

Research shows that a burnout is likely to occur within first few years of one's career (Maslach, 1976). The first time you get ambitious and want to achieve, you don't know how to deal with stress or where to set the boundaries. It could work if you had some support, otherwise you're most likely to wear out. Retaining those individuals could benefit the industry. I know so many people who loved coffee, learned quickly and showed a great potential, who left for other industries.

Occupational stress

Cafe environment is stressful. Overstimulation, emotional labour, physically tiring aspects of the job - that's a lot. These factors are exacerbated in high-volume environment and can wreck havoc on baristas' mental health.

In this article I will define an occupational stress as a feeling of strain and pressure caused by work.

A normal type of stress doesn't have lasting consequences and can have a positive impact. It can increase performance, but only up to a certain level. There's a positive stress up to that level and a negative stress beyond that point it. That is illustrated by a Yerkes-Dodson curve.

The upper curve on the graph is often neglected, but it's relevant to the cafe environment. Overwhelming, negative stress makes cognitively absorbing tasks more difficult. However it doesn't influence simple tasks in the same way. For an experienced barista, making a flat white barely engages his attention. That allows for a conversation with customers or watching a trainee even during busy periods. For this simple task the negative stress doesn't affect the performance as much. It might actually help the barista make the drinks faster. But being more stressed is not a better way to make coffee. Being overly stressed is bad for mental health. The risk is that such an issue will be overlooked, because the performance doesn't appear to suffer.

When is the stress negative? The best explanation is from the United States National Institute For Occupational Safety And Health:

"The harmful physical and emotional responses that occur when the requirements of the job do not match the capabilities, resources or needs of the worker”

Occupational stress is a given. There's no way to avoid it. But it's the sustained strain that should be avoided as chronic stress has a whole range of consequences.

Individual factors:

Genetic (Introversion leads to higher stress levels)
Learned (utilising stress-management techniques)
Personality-based (competitive people experience higher levels of stress)

Environmental factors:

Time pressure (keeping a waiting time below 7 minutes)
A lot of emotional labour (remaining calm in busy periods)
Responsibility (for people or quality)
Long hours and shift working
Inability to have satisfaction of finished product (being forced to produce drinks of suboptimal quality)
Poor working conditions (small space or distant bathroom)
Lack of control (not having autonomy)
Lack of support (no training or feedback)
Weak working relationships (with colleagues or management)
Unclear job description (can I handle food?)
Unclear company objectives or values (what are company standards?)
Lack of communication (last minute shift-filling)
Low pay and lack of career prospects (no professional development or pay-rise scheme)

Chronic stress and its consequences

When individual lacks work-life balance, high levels of occupational stress can lead to a chronic stress. That condition has a wide range of consequences. Poor sleep, anxiety, irritability and lack of concentration, substance abuse and chronic illnesses. For company, it results in increased sickness absence, high turnover and decreased productivity.

Permanent stress could cause burnout or rust-out. Both conditions lead to anxiety and depression.

Lack of respect

In a healthy working environment employees are respected. People valued as professionals are generally more satisfied with their jobs. Lack of that creates a set of problems leading to occupational stress and depersonalisation of workers. There 2 types of respect in the workplace.

Owed respect
That should be a given. At all times, regardless of performance. It includes fair pay, professionalism, expressing appreciation of personal identity, supporting personal development and trust.

Owned respect
That is dependable on worker's performance. It's about recognition of good work. People acknowledged for their success will want to repeat it. Whereas in a culture where there's no incentive to do more or better than an absolute minimum, the quality of work suffers. That respect should be expressed regularly and directly.

Abusive environment and labour cost

Tight profit margins incentivise abusive environments. The most dreadful thing is a labour cost. When company starts pushing it too much, things go downhill.

Speaking from my experience I had stayed overtime unpaid on multiple occasions. Often my manager knew, but was pressured to cut down the labour cost. I was also told off for fussing over details - such as cleaning the drip tray or tip of the steam wand. In order to have the satisfaction in finished job and the environment in which I'd enjoy working I was staying overtime. For free.

On another occasion, I was doing a weekend shift requiring two people. Quality of my work would suffer if I was alone. The day before I learned the other person was not coming. I got a permission to find someone to fill it in. But even though I checked a couple of times with upper management, that person was never paid for that shift.

Decreasing labour cost as a business objective leads to other things as well. Cutting hours makes people overworked and less gets done, along with a decreasing quality of drinks and service. Cutting numbers of people on the shift has an even more dramatic effect. A human being is not a machine - doing two persons job is not effective and far from sustainable.

The most ridiculous thing I heard was when someone from top management said he loved when people are sick, because it drives the labour cost down.

What the fuck was that?

Meanwhile, no one in the room said a word.

Sick pay is another thing. A lack of it makes people come to work anyway. I remember one day I came to work with a throat inflammation, unable to speak. You can imagine the customer service that followed. If people were paid sick days, they would not risk their condition getting worse or making other staff sick.

Burnout

Burnout is associated with being overworked. But is not a synonym for a job dissatisfaction. Someone who is just not happy with their work might become excited when offered a promotion. People experiencing burnout would be dissatisfied with opportunities for personal growth and development on the job (Maslach, 1981).

A burned out person will suffer from 3 main disorders:

Emotional exhaustion - lack of psychological energy, being unable to perform emotional labour, low mood, irritability, constant anger
Depersonalisation - inability to feel a sense of self, as if thoughts or feelings didn't belong to you, loss of identity, emptiness
Lack of purpose and meaning - social withdrawal, negative thinking, depression, suicidal thoughts

I would argue that coffee professionals are more likely to experience burnout. So many of us have huge passion for what we do. And we are ready to sacrifice for coffee. However, highly engaged, committed and ambitious people are more subject to burnout (Maslach, 2001). Accepting to work below Living Wage, staying longer to cover gaps in rota and putting a lot extra are common. There's nothing wrong with strong commitment and integrity, but there have to be boundaries. I've seen models where 'going the extra mile' aka 'we actually expect from you more than what's in your job description' was encouraged.

The process of burning out
According to Herbert Fraudenberger there are 12 steps of burnout (Fraudenberger, 1974). It's difficult to acknowledge them if you suffer from depersonalisation. If you notice someone advancing through these, raise it up. You could save someone's career or mental health.

12 steps of burnout:

Excessive ambition or need to prove yourself - seemingly harmless especially when you want to progress, but leads to further steps. "I wanna be a roaster"
Pushing yourself to work harder - staying after hours, engaging in new projects, competition etc. Work&life balance has already shifted at this point "I know I cleaned the fridge yesterday, but I'm gonna do it again anyway"
Neglecting personal care or needs - less sleep, skipping a meal or choosing not to socialise in order to work. "I will not go home until I finish my signature drink, even though it's 10pm and I'm opening tomorrow"
Displacement of conflict - with inevitable mistakes come inability to own them and excuses. "Sorry, it must've been my colleague putting the order through wrong"
Changes in values to validate self-worth - values, friends and family become dismissed "I don't care about weighing shots for lattes"
Denial of problems and blame - blaming the environment and people around "It's the manager's fault"
Social withdrawal - isolation "Sorry guys, today I need to work on something, maybe next time"
Behaviour changes - people around you see apparent changes "No, I'm fine, I'm just trying to focus on work"
Confusion of identity - depersonalisation, seeing oneself as not valuable, neglecting one's own needs "I don't care about coffee anymore"
Inner emptiness - anxiety, feeling useless, tired. At this point you're likely to abuse alcohol or drugs to overcome these feelings "Let's just get properly drunk tonight"
Depression - indifference, hopelessness, exhaustion "My life doesn't have sense"
Collapse - suicidal thoughts or attempts "I've just imagined jumping in front of this train"

It's not just work that leads that far. It's a combination of things. It's about a skewed life balance and a lack of support network. Focusing heavily on work and trying your hardest for an extended period of time is disastrous.

I'm not an occupational therapist and my understanding of the subject is limited. But I have experienced all the stages of burnout. The quotes are my words. From the social withdrawal to the last stage it went down very quickly. Fortunately I didn't spend a lot of time in the last stage. But that's only because I had a person I could ask for help.

Having the support is the most important thing.

I'm eternally grateful for having that opportunity.

But there's also a second condition which seems harmless, yet could lead as far as the burnout.

Rust-out

This occurs when there's a lack of engagement. Rust-out is usually caused by a shallow, meaningless work or when the majority of tasks are far from what you would like to be doing.

Imagine if somebody wanted to make coffee, but they are forced to stand at the till and take orders entire day. Or when someone spent too much time on the bar and sees no meaning in making coffee in that environment anymore. For example when barista wants to make great quality drinks, but his head barista doesn't care as much (by pushing the waiting time more than quality). It's hard to stay motivated in such environment. It's not obvious, but it's also very stressful.

Rust-out stems from the chronic stress. However this stress is not coming from doing too much. Unsuited job demands, inability to have satisfaction in finished product, lack of autonomy or support, poor communication and no career prospects are its main contributors.

A good question to ask yourself if you suspect being rust-out: would I mind if I was fired?

If losing that job doesn't stress you more than the job itself you might suffer from the lack of engagement.

What to do if in Burn/Rust - Out

There's a number of interventions that could be made. At first, I recommend looking at the working environment. It's also a great idea to learn how to deal with stress and create more balance in your life. Alternatively, you can work your way out of the situation.

Working environment
There are always environmental factors. They are difficult to change. Definitely speak to your supervisors. Almost everybody wants to avoid the cost of staff rotation, so it's in company's interest to help you. There are many interventions you could ask for:

Decreasing volume/ intensity of work - is there another location with less volume? Could you reduce your hours? Or maybe even take a longer holiday (also knows as a career break)?
Enlarging your job - any chance for promotion? New tasks, new responsibilities?
Enriching your job - creating more satisfaction, doing things you already do better, focusing more on quality
Changing physical environment - air conditioning, heating, appropriate lighting etc.
More autonomy - ability to choose location, guest coffees or working hours
Support - is there a personal development scheme, could the company cover your competition costs or sponsor courses?
Improve work relationships - get closer to people you work with, particularly your manager
Clarify your role - ask for feedback, ask if you meet the company's objectives, go through your job description with your manager
Don't take your work home - leave work problems at work, don't think about them at home, don't check work email. Communicate you would not respond to work-related messages after certain time. You need strict boundaries.

Finding meaning and identity
It's important to find your inner self - your identity. Depersonalisation is one of the worst manifestation of burnout/rustout. Practice self-awareness, focus on your thoughts and feelings. Embrace them. Talk about it with people you're close with. Let them talk about you and listen closely.

Establish who you are, what you want to do and what you find meaningful. Follow it.

Name your values. Are you career focused? Is money important? Ethics and integrity over performance? Align your environment to them. You don't want to overwork yourself when you want to have a meaningful family life.

Notice your negative thoughts
Negative thinking takes form of negative distortions, for example: overgeneralisation, catastrophic thinking, polarising, unsupported extrapolations or taking things personally. "I was criticised at the meeting, surely I will be fired" or "I didn't reply to my boss's email within 2 hours, I can forget about that promotion".
They occur automatically, but if noticed, can be addressed and changed. If you practice self-awareness, you might be able to work through some of those distortions on your own. If deeply rooted and difficult to change they may call for a therapy.

Lifestyle and well-being
Sometimes stress is referred to as an indicator of not being mindful. You want to be able to deal with stress and relax. Meditation is very helpful. If you don't know how to start, download Headspace or Oak (free) app on your phone or find guided meditations on YouTube. Like this one.

It's important to eat and sleep well. Staff meals usually don't provide for long, intensive shifts. Make sure you eat enough, being stressed makes you less hungry than you should be. Learn more about quality sleep - aim for at least 7 hours, wind down and put that phone down an hour before bed. If you struggle to fall asleep early, reduce caffeine after 2pm, get earplugs (silicone ones are super comfortable) and meditate.

Cut down alcohol. If you drink every single day after a shift - you have a problem. Even if it's nowhere near addiction, that's a disastrous habit. As long as alcohol is metabolised, you body will not regenerate or fall into a deep sleep.

Take care of your body. Stretch after work, do yoga or go swimming. If you're active, you get stronger and work becomes less tiring. If you consider serious running - I would recommend factoring in the standing nature of your job.

If you experience pain on the job, LET YOUR MANAGER KNOW. Maybe it's just your poor technique, early stages of RSI or something that will force you to quit coffee and affect for the rest of your life. It's not worth being quiet about it.

Working your way out of the company

If you didn't get the support or were unable to change environmental factors you might consider an exit. There's a chance the company doesn't have resources or capability to help you. It could also have a toxic culture and treat you like an expendable commodity. You could simply change jobs - doing the same thing. Or look into a career progression.

But you need to tread very carefully. You don't want to burnout doing that. Considering your work&life balance, shift focus from paid job to personal development. Yes, your performance might suffer and meeting the company's objectives might be more difficult. But you have to do what's right for you.

It's good to have a professional goal. It goes in line with finding meaning. Often, the best way to progress is to change company. But you might be in a position where it makes sense to stay for another couple months. Use space and resources available to your own advantage. Increase your value on the job market. Enter competition, take courses, organise events, find a mentor or start a professional blog. There's very little you need to enter Brewers Cup or organise a cupping.

Summary

Instances of chronic stress, burnout and rustout don't mean that affected individuals are bad employees. Conversely, they are ambitious, value-driven high performers who believe in quality and growth. Very often it's the company that should take the blame. Having a recognition system and intervention plan is very important. Entry-level coffee professionals struggle to live in a healthy, balanced way. Often they feel lonely with their problems and are not able to afford to properly take care of themselves.

Having a career is tantamount to experiencing a lot of the occupational stress. Wherever you can, reduce it. Learn how to deal with it as much as possible. Stay self-aware, find your boundaries and don't cross them.

If you notice first symptoms of burnout or rust-out - slow down and take care of yourself. It's never worth to push beyond your limits. Meaningful, long-term solutions are about sustainable use of your resources.

Life balance is a complex, interconnected web. Throughout time, the focus may shift. But whatever you pursue, never neglect your values or yourself.

I would like to finish quoting one of my best friends, who I used to work with on an extremely busy bar, making 1400 drinks a day. This sentence inspires me to this today:

We're already under quite a lot of pressure, let's not stress each other more.

Many thanks to everyone who helped in the process of writing this. Stories and experiences that have been shared with me, greatly enhanced my perspective on the topic.

References:

Bamber, M.R., (2011), Overcoming Your Workplace Stress
Brosnan, L., Todd, G., (2009), Overcoming Stress
Clouston, T.J., (2015), Challenging Stress, Burnout and Rust-out
Cooper, C., Kahn, H. (2013), 50 Things You Can Do Today To Manage Stress At Work
Evans-Howe, S. (2013), Managing Stress At Work
Fraudenberger, H.J. (1974), Staff Burn-Out, Winter
Maslach, C., Schaufel, W.B, Leiter, M.D., (2001), Job Burnout, Annual Review of Psychology 51(1), 397-425
Maslach, C., Jackson, S.E., (1981), The measurement of experienced burnout
Szczygiel, D., (2009), Emotional Labour in a Service Industry - definition, theory and research. Psychologia Spoleczna, 43(11), 155-166

Pictures (in order):

Photo by Daniel Chekalov on Unsplash
Photo by Tim Mossholder on Unsplash
By Yerkes and Dodson 1908
Photo by Eric Ward on Unsplash
Photo by Stefano Pollio on Unsplash
Photo by Ryan Whitlow on Unsplash
Photo by Duncan Kyhl on Unsplash
Photo by Nathan Dumlao on Unsplash

Podcast #4: The Tale Of Becoming a Roaster

2018-05-06T13:47:00.000+01:00

It's all true story, despite the title showing differently. This episode reflects on what I did on my way. Because even though it didn't feel that way, all the skills I've acquired up to this day are useful in my job.

I think this one is a bit more fluid than last one. However that was over a year break, so I felt a bit rusty anyway.
Enjoy!

Photo - Vladimir Proskurovskiy, Unsplash

Water filtration and its effects on coffee

2018-04-08T12:24:00.002+01:00

Water is probably the most difficult topic in coffee. You need a basic understanding of chemistry to even be able to explain how a filtration system works. It is hugely important that baristas and roasters understand how water impacts their coffee.

For the sake of that, I feel a need to write a few words about a major contribution to water quality - filtration.

Before diving in, I'd like to disclaim how humble my experience in the topic is. My chemistry knowledge is at best around the 8th grade level. I have only worked with filtration systems provided by 3M and BWT. I have only made coffee professionally in London and around. I have not even read Water for Coffee (a few short extracts only).
I will list my references at the end of the post.

As a coffee professional, I pride myself on being able to taste hardness of water through the coffee. I'm aware that I'm able to do that only in certain conditions. And even when I'm convinced I test the water anyway.

I owe that skill to great training and experience of working with badly maintained water treatment equipment.

Water filtration systems

There are many types of water filtration systems. It's important you understand how exactly your system works.

1. Softener - Calcium and Magnesium are exchanged for Potassium or Sodium. That method doesn't change alkalinity (what we like to call carbonate hardness). Thus it's an unsuitable solution for high alkalinity water (like London), coffee will be flat, lacking acidity and more bitter.

2. Decarboniser - Calcium and Magnesium are exchanged for Hydrogen. Change in alkalinity equals the change in hardness (theoretically). This method lowers the pH of the water, increases its CO2 content. I will outline its dangers later, describing Carbonate Cycle.

3. Demineraliser - ion exchanger or Reverse Osmosis. Those remove minerals from water, both alkalinity and hardness are reduced, no additional Carbon Dioxide is produced. The results of measuring RO water and single cartridge filtrations are non-comparable.

The list is not inclusive.

How to test the water

To avoid situations when filtration is impacting the taste of coffee in a negative way, I needed to be on top of water testing.
I've designed a sheet to help with that.

For that, I used a BWT water testing kit, thermometer, conductivity meter and pH meter. Let's describe them:

BWT water testing kit - after researching titration methods I'm not sure what exactly is measured. It states it measures "Total hardness" and "Carbonate hardness". I could not figure out what indicator is used for the former, but the latter is most possibly EDTA.

Thermometer - the temperature will affect other readings, particularly pH and conductivity

Conductivity meter - so-called TDS meter, it's a quite inaccurate tool, but in a particular setting with sampling at the same temperature, it can provide valuable information. Measuring hardness with this on decarbonising filters could trick you. It might serve as such an indicator when using RO.

pH meter - knowing pH and level of carbonate hardness you can derive CO2 content in your water. Why would that be important?

Carbonate cycle

There is a correlation between pH and form of carbon in the water. Specifically, how much carbon is present in the forms of Carbon Dioxide, Bicarbonate and Carbonate.

I understand this is a simplified, partial explanation of the carbon cycle, but we don't need more to understand how water filtration works.

Let me illustrate that:

The amount of Carbon Dioxide in your filtered water matters a lot. When the water containing a significant amount of CO2 enters the espresso basket, it creates additional resistance. It does so in an identical way as a freshly roasted coffee.

You can check how much Carbon Dioxide is present in your water if you know its Carbonate Hardness and pH.

Unfortunately, a very popular method based on Decarboniser Cation Exchanger produces a lot of Carbonic Acid, which leads to excess dissolved Carbon Dioxide in the water. That may explain why you need to degas your coffee for longer than recommended to reach its peak extraction.

Have you ever noticed that cafes with RO degas their coffee for shorter periods while using the same coffee?

Summary and outlook

I'm far from saying RO filtration is superior. For a long time, I was convinced that RO removes too much Magnesium, which is a flavour carrier. I'm not as convinced about it as I used to. I would need to do more research on that.

Another theory I have is that RO based coffee shops would benefit more from decreasing the pressure on their machines.
My reasoning is that CO2 creates additional resistance - so a barista would make the grind size courser to compensate for that and achieve reasonable contact time. But that leads to underextraction.

Now whether that CO2 comes from coffee being very fresh or decarboniser as a water treatment tool it doesn't matter. Increasing the pressure would put more force to counter the resistance of the basket, coffee and CO2. Do you find that very freshly roasted coffee benefits from higher machine pressure?

Understanding your water helps to understand your coffee. For now, this is still a new and unexplored topic. Definitely, it's not common knowledge even among roasters and coffee shop owners, let alone baristas trying to make their coffee taste good.

You can find more information on the hardness of the water on aquarist's forums - that hobby seems to attract more chemists - than coffee ones. There are great things happening thanks to people like Chris Hendon. People are making their own water for coffee. Products like Third Wave Water and Peak Water get a lot of attention. That's great! But don't forget about water in high volume operations.

I encourage everyone in the coffee shop, roastery or on the competition stage to take water seriously and be aware of its impact.

References and links

- Folmer, B. The Craft and Science of Coffee; Elsevier Science, 2016.
- Titrations.info EDTA - determination of water hardness
- Chemistry.bd.psu.edu - Determination of the Hardness of Water
- SimplyDiscus - Relationship between CO2, KH and pH

- CO2 Graph

- Title Photo by Imani on Unsplash

15 vs 18

2017-12-29T12:30:00.000+00:00

Let me take you on a journey. The journey of sweet espresso, reliable grinders and cost efficiency. With one piece of equipment:
A filter basket.

The post covers 6 months of experimenting with different doses in VST baskets. My hypothesis is that 15g dose tastes better than 18g dose on the same ratio, whatever that ratio would be.

This is not even touching the scientific method. All my thoughts and conclusions are questionable and I'm open for debate.

I did my testing on Victoria Arduino Mythos grinder. To understand the relationship grinder-basket I did my best to explain how this grinder works. I hope some of you will at least take that away regardless of your basket choices.

The article covers:

1. Theory and its practical application for VST baskets

2. Mythos - the way it works, when it overheats, how to prevent it

3. Puck saturation rate and what it means for extraction

4. Thermal equilibrium as key to understanding physics behind saturation temperature-wise

5. Experience of using bigger baskets and bigger doses (a bit of data)

6. Why would I increase the dose?

Theory of VST

VST has put tons of research into their coffee baskets. It feels as if someone for the first time thought about shape, holes' diameter and placement and extensive QC of every single product to follow.

I have been part of a research group working with one of the espresso machine manufacturers. As a part of the research, we've been testing different baskets. VST baskets had the best results. All the testing followed the scientific method. I'm not allowed to share any more of that, but I wanted to show that some people have proven VST baskets superior.

In theory, the variance in hole diameter should compensate for different doses. Total Open Area changes between sizes. 15g dose in 15g VST basket should have pretty much similar grind size to 18g dose in 18g VST basket.

Is that true? I answer that later in the text.

Mythos

At the moment my favourite espresso grinder. The best espressos I ever had were made using Mythos. Also, Mythos is easier to operate in 12kg a day environment (where I did most of my experimentation).

The grinder was built to create the most consistent grind size and particle size distribution during the day. The idea behind it is to keep the grinding chamber in the 35-55 degrees range. It should never be cooler than 35 degrees. It should never be higher than 55. The grinder has a complex heat management system. It consists of:

Heating element. It's placed in the heat sink. Warms up the grinding chamber. I guess it should turn itself off upon reaching 45 degrees, but I'm not sure about it. Some people like using Mythos with the element unplugged. It does not warm up coffee though, so the beans don't get much hotter before grinding. It just helps the grinder reach and maintains working temperature - you dial in on a warmed up grinder.

Some people "determine" temperature of the grinder by touching the heat sink. And when it seems too hot to touch they say: "it overheats". Not exactly.

The way to measure overheating is by measuring the temperature of the grounds. When those exceed 50 degrees, the grinder has no capacity to cool them down if you keep making coffee. The grinder overheats when grounds are hotter than 55 degrees. Period.

A thermal equilibrium will be too high when grounds reach 55 and above (I explain the term later). The result is as if you used extremely hot water to brew an espresso (like 96 and more). Many bitter compounds in a roasted bean need a high temperature to extract easily. And with temperature equilibrium being too high, you extract too much of them.

The excessive heat is meant to be taken away by fans. There are 2. One, on the back of the grinder, sucks air in - therefore the temperature of the environment is important. The second, on the right side, blows the hot air out. They turn on when grounds temperature goes over 35 degrees. A few doses ground is enough unless the environment is really cold.

Over 40, fans turn on second gear and the air is blown away with significant force. After an hour of continuous service, grounds are over 50 degrees and the blown air over 40.

At that moment the heat sink has huge thermal energy and fans are barely able to keep grounds under 55 degrees. In most cases they are able do it. But at that point, the heat sink has accumulated enough thermal energy to keep the grounds above 50, even if you stop making coffee for a while. It takes around an hour of not grinding for fans to cool grinder to 35.

The fans are not big and powerful enough to drag the thermal energy out of the grinder (that is being improved in the next generation).

There have been very few occasions when I experienced overheating Mythos:

1. Broken fan

2. Unreasonably fine grind size - which causes a decrease in extraction

3. Particularly tricky coffee - light roast Pacamara for example, resulting in grinding time of 20 sec at 15g dose just after 1kg of coffee used

4. Lack of proper cleaning - which I explain in the next paragraph.

Victoria Arduino recommends cleaning behind the bottom plate (the part with moving burr) weekly. The factory-new grinder can get clogged with as much as 15g of coffee behind the bottom plate (also called backplate) after using only 1kg of coffee. I think the grinder should be cleaned every 8kg with a deep clean at least once a week.

I deep clean Mythos grinders for over a year - without any negative consequences. Only in that way you can ensure the grinding chamber is 100% clean. The part is designed to be taken off regularly, both the screw and thread bear unscrewing better than 4 front screws for heat sink (the part with static burr).

The tricky part about the deep clean is a reverse thread on auger (which is a nut for the bottom plate), but the shape of the bottom plate helps with determining that. Also, you have to be careful with putting the plate back on the shaft. Its shape is almost fool-proof, but I've seen it assembled wrong - the result was a deformed bottom-plate made from soft aluminium. The fix required 2 people, screwdriver, hammer and a new bottom-plate (£25). Along with working grinder, you get complimentary dents on the grinding chamber.

Some heavily used and badly maintained Mythos grinders have trouble spinning the spindle. I suspect coffee dust being pushed into the motor and its bearings. Additional resistance on the motor makes the grinder slower and potentially heating up even more. The motor is one integral part and it's quite expensive. Also, it requires a qualified technician to install (not sure if you'd even get it if you're not one). That could've been avoided with proper cleaning.

Now that we know how Mythos works, let's dive into puck saturation rate. My favourite topic in the last couple of months.

Saturation

Puck saturation rate - how quickly the entire puck gets saturated with brewing water.

The faster puck saturation rate the more even and higher extraction (given reasonable dose/grind size/temperature/pressure etc). If grounds across the entire bed have the same contact time with water, in theory, they should extract more similarly. As opposed to the top of the puck being in contact with water much longer than the bottom.

But what's crucial when we talk about saturation rate is temperature. The temperature of slurry (brewing water and coffee) is not uniform across the puck. The temperature is highest at the top of the basket and lowest at the bottom of the basket. We can talk about temperature equilibrium in espresso - but that's an average, not an absolute value.

Now, coming back to the grinder for a second. Grinding increases the temperature of the grounds. Mythos keeps those grounds in 35-55 range - which in itself creates more consistency. Warming up the grounds makes the saturation a bit faster - good! So why not bring up the grounds as hot as possible?

Gwilym Davies said that when developing the Mythos they experimented with different temperatures. And grounds above 60 degrees never made good espresso. Also warming up the coffee changes particle size distribution, not in a way, we would like to.

The factor that affects saturation rate most is the depth of the coffee bed.

Lower coffee bed means better saturation.

When water at 93 degrees gets in contact with grounds at 35 it cools - thermodynamics. The further down the puck, the more it cools, even down to 40 degrees. Colder water has less energy. Less energy = less extraction. Of course, that water is displaced with fresh hot water. But even that new water won't reach past equilibrium point - brewing lasts only so long.

Temperature equilibrium

I've touched on this subject earlier, discussing the saturation and temperature of the grounds. But reaching full saturation is far from reaching thermal equilibrium (TE). Understanding TE is key to understanding saturation. Although it's only about temperature.

Thermal equilibrium is when 2 things at different temperatures mix with each other. In our case, ground coffee and brewing water. To calculate it you need weight, temperature and heat capacity of both materials.

Heat capacity sometimes referred to as specific heat, is how much energy is needed to change the temperature of an object. Specific heat of water is 4.18 joules per gram per Kelvin. Specific heat of coffee is assumed to be around 1.4 j/g/K (like dry wood, following Matt Perger in that matter).

The specific heat of water is higher than that of coffee. What does that mean?

It's much easier to heat coffee than water. It makes sense when you think about how much heat grounds absorb from grinding. During extraction, brewing water is the same temperature. But grounds temperature will vary during the day (within 20 degrees if you're using mythos).

In theory, regardless of your dose (keeping the ratio the same), thermal equilibrium is the same. That thermal equilibrium is only 3-4 degrees less than the temperature of brewing water. However, this temperature never is reached. Let alone the loss of heat, time of extraction is too short. So what we can think of is how quickly the puck gets acceptably close to the desired temperature.

The lower the mass in the basket, the faster puck reaches the equilibrium. And you can derive that using logic or transforming the formula.

What happens during extraction: top of the dose is brewed with very hot water. The bottom is extracted with much lower temperature water. The difference between those 2 measures evenness of extraction - bigger difference means less even extraction. With higher dose, not only it takes longer to reach thermal equilibrium, but the longer time for those values to get closer to each other.

The bigger the difference between the temperature at the bottom and the top of the basket at the end of extraction, the less even extraction. The less even extraction, the lower extraction.

The higher your dose, the higher depth of the coffee bed, the less even saturation, the less even extraction, the lower extraction.

Therefore: higher dose implicates lower extraction.

53mm baskets

When I competed in UKBC I used a La Spaziale machine with 53mm baskets. Thus the same dose as in 58mm basket means a higher depth of the puck. Espressos from La Spaziale are more on the bright, fruity side, less complex, less sweet, less coating, easier to get lost in milk.

Regarding that last thing, my milk beverage was 5oz drink with 20g of espresso. It was cappuccino so the ratio of coffee to milk was even stronger as it was more aerated. Practising on 58mm baskets I achieved synergy between espresso and milk. But, using 53mm I got feedback of espresso getting lost in the milk.

Would it be reasonable to create even wider baskets? Nope. As we know it's not easy to create even dispersion of water from the grouphead in the pressurised system. Also, the headspace volume would be altered.

It doesn't matter how much you extract but WHAT you extract.

Let's consider 2 shots on the same ratio but with a different dose. Using a refractometer and 2 calibrated people to evaluate.

17g dose/ 40g yield

TDS: 8,64 (pretty much standard, good for the ratio)

Extraction %: 21,18 (quite high)

Scoring according to WBC:

Acidity: medium to high, unpleasant

Sweetness: low to medium, caramel-like

Bitterness: medium to high, without any flavour attached

Balance score: 3

Aftertaste: 3,5

The body high, but tactile not pleasant, harsh, lacking smoothness

Flavour clarity: flat flavours, lime, chocolate, caramel, no depth or complexity

15g dose/ 35,5g yield

TDS: 8,07 (lower, but still very good)

Extraction %: 19,89 (low, yet better than most London cafes though)

Acidity: medium (pleasant, lime-like)

Sweetness: medium to high

Bitterness: low to medium

Balance score: 5 (that looks optimistic but definitely better than the previous one)

Aftertaste: 4,5 (long-lasting, dragging on lime zest and bakers chocolate)

Body lower on weight, but very smooth, silky, rounded.

Flavour clarity: high, +5 flavours discernible, deep, complex

That example shows that WHAT you extract is much more important than HOW MUCH. Sweetness, flavours and complexity are parts of great espresso. Not a 21+ extraction percentage.

Let me share with you a little table. Different espressos, a similar number of extraction, very different sensory results. Conclusions to be drawn on your own.

That doesn't prove anything and is nowhere close to the scientific method, but gives a bit of context for why higher doses are less sweet.

Sweetness is perceived as weight and smooth texture before our taste buds can determine what taste is it. Therefore it positively affects tactile of the espresso. You can test it yourself tasting mild solutions of sugar.

Would you swap?

What if you consider swapping to bigger baskets for a more drastic change in dose?

I actually did such an experiment.

In the busiest coffee shop I've ever worked in, doing on average over 1200 drinks a day. The workload is split between 2 machines and 5 baristas. One of the machines had 15g VST baskets, the other 18g VST baskets.

We did it for a week. Only. Let me tell you why.

Baristas ended up dialling in on more closed ratios. It seems as if they are used to certain yields and won't let go. I had a similar observation when changing to smaller baskets in the past. Because the ratios were more closed, the intensity of the espressos sky-rocketed. So baristas made grind size unreasonably course to make up for that. And those were some of the most underextracted shots I've tasted in that shop.

That gives a hint that you may want to increase your dose when using darker roast - but I believe it's not your way of making coffee, is it?

15g dose/35g yield is a 2,3 ratio - that's where the blend we used for testing tastes best. On bigger baskets baristas tended to go for 18/36 which is 2 instead of 18/42 (2,3). Any time you increase the dose, you may want to think about the ratio of espresso to milk in milky coffees.

Grinding higher doses gives more strain on the grinder. Total Open Area in VST basket compensates for different depth of the coffee bed. Thus grind size remains pretty much the same on dialling in between baskets. But given the same grind size, grinding higher dose takes longer.

Experimenting on how Mythos heats up, I derived that grinding time has a much bigger impact than grind size. That's why the prototype with high-speed motor doesn't heat as quickly as low-speed. Reaching 8s of grinding time upon peak period makes the heat sink very hot (65-70 degrees) and grounds are at 55.

15g dose on average gives 5,5-6s grinding time on Mythos used for testing (low-speed version).
18g dose started at 7.9s with too course setting (18/36 ratio) and 8.5s at the correct setting (18/42).
That means grounds at 40 degrees after dialling in and a huge potential for reaching 50 degrees in an hour (it takes 2,5h on 15g dose).

Let's look at the data below. The first picture shows recipes before the swap. The second recipes on 18g VST baskets. I suspect someone was moving a grinder setting dial, thus numbers on the first picture vary a lot. On the second it is trustworthy.

When the grinding chamber temperature increases, the particle size distribution changes. You have to decrease the distance between the burrs to keep contact time the same. Which increases grinding time even further. And because that heats up grinder, even more, you end up having a FINER grind size on 18g during peak time than with 15g.

Real life story:

My favourite customer walked in. I nodded and started making his coffee - I asked my colleague for a double shot in a piccolo glass. She tried. 3 shots in a row failed to meet a bottom limit on contact time (29s in that case). Barista on shots sworn to God that she had just made it finer. The fourth try was servable - I was glad I had known the order before ordering.

Then the service picked up, grinding time went well past 9 seconds, which slowed down the workflow. The downward spiral of killing the grinder began. The grounds were at 55 degrees at least. The grinder was about to overheat. We tried dropping water temperature, but it deprived espresso of any sweetness. It seemed the equipment couldn't make coffee with more sweetness than bitterness. Then the grinder started making weird noises - the setting was extremely fine - the strain on the motor was horrendous.

That day the 18g baskets equipped machine got cleaned first. During clean-down I opened the grinder, holding the heat sink through wet cloth to avoid burns. That grinder didn't look like cleaned the day before (it was).

Let's taste it!

On the sensory side, baristas were not happy with the taste balance of the shots. Lacking sweetness and pleasurable tactile. In milk drinks, the synergy deteriorated. Not a single flat white scored above 3,0.

Having decaf on Mazzer Robur on the 18g basket side I got back to how old baristas were teaching me dialling in. "Make it somewhere between sour and bitter". Being unable to make espresso scoring more than 2,5 is a shitty feeling when the beans in the hopper are decent.

On the financial side, 3g higher dose meant 7kg more coffee used to produce the same amount of drinks in the week.

Why would you increase the dose?

I heard that in Prufrock everyone on the shop floor has to agree if somebody wants to change the dose more than 0.5g (is that true by the way?). Initially, I thought it's ridiculous.

After further contemplation I understood. Changing the dose changes the mechanics of extraction. Different headspace, different resistance, different saturation rate. Too much to deal with.

I almost never change dose more than 0.5g on one coffee and more than 1g between different coffees. If I reach extremes that are either down to roast, equipment or water quality.

As Ben Kaminsky found, roastiness in espresso is hardly perceivable above 10% TDS. Very soluble roasts will extract easily and be more bitter - you can counter that with underextraction. I assume darker coffee of lower density will have the lower thermal capacity - reaching thermal equilibrium faster. Makes sense when you think about a contact time for very dense coffees like high-grown Kenya).

Dull burrs will increase bitterness and underextraction could be the key to balance. But that should not happen in the first place.

Water with high ppm will produce less sweet coffee. Sometimes mineral, very often flat. Having more closed ratio will increase TDS of espresso, decreasing perceived minerality (like roastiness). Flavour clarity reaches its best at underextraction with hard water.
Water's impact on coffee goes beyond that. Your water might be ok, but much different from water the roaster used to test that coffee. I like to think that water and roast work in conjunction with each other.

Today I agree with Prufrock's approach. Unless something extreme is going on, big changes in dose are unreasonable. Assuming baristas know what they're doing and are calibrated with each other.

Conclusion

Different sizes VST baskets will use similar grind size. But the amount of ground coffee will affect the time of grinding. Time of grinding is a key factor in heating up in Mythos.

Low depth dose will be saturated quicker. The difference between the top and bottom of the basket will be smaller. And the entire puck will approach thermal equilibrium point faster.

Faster saturation will allow for more even extraction. Even extractions are higher than uneven extractions. But WHAT is extracted is more important than HOW MUCH. We aim for sweetness, flavour clarity and nice mouthfeel - not necessarily weight.

Change of dose is a risk. Make sure, you have very good reasons to do so. Check your equipment, water system, train your baristas on puck preparation and sensory of espresso. Keep in mind that change of dose has to change your ratios and will change unit costs.

All of the above expresses my opinion at the very moment of writing it. I hope to deepen my knowledge and tune my ideas about the topic. I consider it all debatable and I'm genuinely looking forward to the conversation.

There are many things I didn't cover around the topic. Most of that can be found elsewhere:

Barista Champs

2017-10-08T20:24:00.000+01:00

Some time ago I competed in UK Barista Championships. The competition left me mentally exhausted. A mix of happiness, pride and disappointment.
It took me a couple of weeks to gather the courage to watch the video recording of my performance. However, due to technical problems, it has not been recorded. Some kind of relief, I have to admit.

I didn't start preparing until the date of the competition was announced. In fact, I haven't done anything until I had chosen my coffee - on the 12th of June. The comp was on the 9th of July. Less than a month. Very tight timeframe for a first-timer. But I wanted to be motivated and very focused throughout that time.

Learning upon Brewers Cup I got most of my equipment in the first week of preparation. Also, I didn't try to save on anything. Quality and design are important. It gives me the confidence to work on good equipment. But still, everything within reason. For example, as long as £30 scale does the job well I don't need any better, but if my existing scale doesn't fit on the drip tray I need a better one.

I was quite lucky to have a chance to work on La Spaziale ahead of the competition. It's quite different from what I'm used to. Particularly establishing a recipe for my coffee before the prep-time.

I did a lot of run-throughs, more than with Brewers Cup. But getting people to watch and judge me is crucial. I didn't have it as much as with Brewers. This kind of feedback is necessary to do well. I was planning to do them in the week before the competition, since I had everything ready a week before. Unfortunately, some unexpected events popped up and I couldn't get people to see me. My fault in planning.

In some areas, I was more prepared than with the Brewers Cup, particularly espresso and my speech. Others, such as signature drink and milk drink, not as much. And that comes down to the goal I had set for myself. I didn't even have an idea what I want to do with sig drink and milk drink, so any positive outcome was good enough.

I felt very confident and quite excited before the performance. Smooth set-up, last changes regarding which cloth would suit be better. Some stickers on glasses that I've noticed in the last moment. Another glass breaking in my hand while setting the table (that one was cheap).

My music is on and I'm rocking it.

Well, almost.

The grinder was consistent, only my mistake made me waste a full dose of coffee. Shots were running as they were supposed to. Judges smiled. I smiled. Had an eye-contact while steaming milk. Even managed to look them in the eye while pouring. No shaking hands.

But steaming milk and watching shots was a bit too much of a stretch. Particularly that I failed to tare the scale (which I didn't realise).

Boom! Damn it...

Stopped the shot way too early.

Without hesitation, I had announced I needed to remake those shots. As if nothing happened. That confidence surprised both me and the spectators. Well, it's okay to screw up, right?

Not quite.

Before preparing the signature drink I had only one minute remaining. Sig drink takes more than two minutes.

"Moving swiftly to signature drink..."

I rushed it. Inaccurate dosing, too much ice, not enough shaking, didn't serve the whole espresso.

Went overtime. 16.06 - disqualified by 6 seconds. I knew it already when looked at the timer while shaking the sig drink.

They knew I knew. I loved how Maxwell said: "my favourite phrase: moving swiftly to sig drink...". After all, then we could only laugh about it.

After that, I didn't know what do to with myself. All that was left was the feedback from judges. Which didn't lift me up. I was annoyed by the mistakes I had made, like not flushing the grouphead.

It only took someone else to point out that my espresso scores were pretty good. I still need to learn not to focus on negatives and appreciate positives.

From the positives, I achieved my goal for espresso scores, 3/3,5/3,5/4 across 4 espressos. Not too bad.

Next time, I need to work more on different parts of the routine. Think about how to avoid technical mistakes, what to do when the shot goes wrong, have more clothes. Not be afraid to ask people for help.

I'm happy that I have experience in the most difficult coffee competition. I served a drinkable espresso, stayed calm under pressure, figured out sig drink - which seemed impossible beforehand.

I am going to compete next year, even if just for the sake of not making the same mistakes again.

Since the video is not recorded, I'm going to use this post to give thanks to everyone who helped along the way.

I'm profoundly grateful to Diana for inspiring me to compete, suggesting little details having an immense effect on the score, answering last-minute questions, making sure I would manage to prep and show me good things on the score sheet. Big thanks to Leo for helping with prep, tasting things and being present on the day - the only one, an absolute legend. Big up for Jamie and Andrew for help with choosing coffee, suggestions and scoring my coffee.

Main picture - SCA UK Instagram

How I became a TED speaker

2017-07-30T18:40:00.001+01:00

Some time ago I did something I had dreamed about.

I delivered a TED talk.

How did it happen?

Public speaking

I started being interested in public speaking in high school. I wanted to become good at it. I volunteered for school presentations, started reading books and articles on the subject.

Then I heard about Toastmasters. A non-profit organisation where you learn how to speak. I committed myself, going through the educational program as quickly as possible. I took part in the International Speech Contest, winning on 3 consecutive levels. That exposed me to the world-class competition. I was only 19 at the time.

After that, I started speaking out of Toastmasters. I was delivering training sessions on public speaking and web-writing for media people. I didn't get paid for that, but I enjoyed it.

The problem was that speaking about public speaking is an oversaturated market. I had the delivery skills, but not much to convey.

I needed to become an expert on something.

Coffee

In the meantime, I started working as a barista. I fell in love with coffee. I left the university, decided I want a career in coffee and forgot about public speaking altogether.

I started writing a blog about coffee, taking part in competitions and became a part of the coffee world.

People started to associate me with coffee.

I've become a trainer. That was my goal before I got into coffee. However, even with the public speaking background, it wouldn't be possible without full commitment.

TEDx

One day, I opened my inbox and I couldn't believe what I've seen.

"Hey, what are you doing on TEDxBielsko-Biala and why do you have a speech about coffee?"

A typical cheeky polish way of asking somebody to do something.

I didn't feel ready. I didn't feel good enough. I almost rejected this opportunity.

Fortunately, my mentor convinced me I have something interesting to say.

The speech sparked a lengthy conversation at the conference. People were genuinely interested. My goal has been achieved.

I know my TED wasn't perfect. I didn't prepare as much as I should. But it is one of the most fulfilling thing I've ever done.

Pictures - courtesy of TEDxBielsko-Biala

Barflow Ergonomics

2017-05-28T20:03:00.000+01:00

Have you ever experienced pain behind the bar? Have you had a work-related injury? Or you know somebody who had?

Personally, I answered "yes" to all questions above.

Whether you pursue a career in coffee or not, health and well-being are essential in physical work.

I have a friend who used to work as a barista in high-volume cafe. In less than a year he messed up his shoulder permanently. This affects him every single day. And I guess it all comes down to improper tamping.

How to improve ergonomics behind the bar?

Weak points

1. Shoulder - predominant joint in coffee-related injuries. Wrong tamping or reaching overhead hundreds of times will ruin your shoulder. If there's an issue with your posture, like winged scapulae, this will escalate quickly.

Quick fix: stretch your chest and strengthen the rotator cuff muscles

2. Lower back - lifting, bending and standing long hours expose your spine to unnatural forces. Sitting in front of a computer after work makes things only worse. Back pain can be paralysing and gets more serious with age. Think about your posture when lifting.

Quick fix: bend knees, not spine, keep weights close to the body, engage abdominal muscles.

3. Knees - standing job affects your entire legs, but the knee is structurally the weakest joint in your body. It's great dealing with vertical forces, but fragile in other dimensions. Overextension, bad shoes, lack of standing mats - the knee takes it all, badly.

Quick fix: get supporting shoes and stretch your legs (from hips to ankles)

The examples above are the most common in bar injuries. They can also put a stop to your career in coffee. Permanently.

Wrist and elbow joints are also exposed, but those are less vulnerable. It's easier to avoid damage. I healed my strained wrists and popping elbows doing a barista job (yet bear in mind those came from extreme downhill racing).

What about a wrist RSI (repetitive strain injury) from tamping you may ask.

Please read below.

Basic rules

1. Proper body mechanics - use anatomical movements especially when force is applied. Picture this: protracting shoulder forward when tamping or circular move when taking a cup from the top of the machine. The shoulder is not designed for circular movements. Unless you take pleasure in popping shoulders with every single coffee you make.

Another frequent mistake is shrugging shoulders to ears when pouring latte art or tamping. Shrugging combined with flexion in elbow puts sheer forces on bicep ligament. Eventually leading to rupture (it will hurt a lot much earlier though).

2. Minimal Range of Movement (ROM) - the shorter distance your arms move the less fatigued they are at the end of the day. Do you need to reach away from your body a lot? Grinder far away from the machine? High take-away cup stacks? Not only does it put more stress on your body, but also slows you down.

3. A minimal number of moves - nobody likes doing a double job. An order of 3 lattes for takeaway. Do you reach 3 times for one cup or grab 3 cups at the time? Pouring milk: grab cup by the handle, pour latte art and place the cup on the saucer while holding the handle all that time.

4. A minimal force applied - particularly addressing wrists. Knocking out coffee pucks, tamping and inserting handles into groupheads. You can perform all those gently. Your wrists will thank you. Also, making minimal noise gives you +5 to being elegant behind the bar.

5. Keep it close - this derives from #2. Try to stand close to the machine, you won't need to extend your arms while inserting handles. It's better to make a step than to reach away from the body. The length of the lever determines force at its base. Lifting any weight at arm's reach multiplies strain on your shoulder and spine.

I express the greatest appreciation for those who take every measure to ensure perfect extraction. But if it comes at the price of health - non-anatomical angles, excessive strain - I don't find it reasonable. How can we talk about sustainability if the barista wears out physically after a year in a busy cafe?

Design your barflow

1. Organise your space - pull grinders as close as possible, halve stacks of cups on the machine, keep lids/saucers/spoons at arms reach.

2. Choose your tools - pick what suits your style and your body.

Tamper - very important. There are several ergonomics friendly choices. Puqpress does the job for you. PUSH Tamper allows you to press at any angle you want. Traditional tamper - choose the most comfortable - light and fitting your hand. Some people like heavy tampers, but even if it gives more control (which I doubt), it's more weight to lift. If you do it hundreds of times a day it could be an issue.

Portafilters - usually you don't get to choose them, but if you have a chance, give it a thought. Their weight, grip comfort and control all matter.

Milk jugs - heavy, sharp edges, useless spout - obvious, but so often neglected.

Bar height - I can't stress enough how often it's a mistake in design. High volume bars designed for baristas 185+ cm is the most ridiculous idea. I've never heard a complaint about a bar being too low. The other way? Dozens of time.

All the ridiculous angles while tamping and shoulder impingement from reaching way above the head with every single shot... Discrimination of short people. Even a gender inequality issue as most women are shorter than men.

The lower the bar, the more comfortable it is. Within reason, of course. Anything above hip level is too high. Fortunately, there's a trend for low profile bars and machines.

3. Swap hands - The simplest way to cut down strain on your wrists or shoulders even by half. Many experienced baristas can tamp and pour basic patterns with their non-dominant arm. If you're not using your other hand yet, give it a try.

Why?

Muscular imbalances between sides of your body, leading to scoliosis and pelvis rotation. Accumulated strain on one arm. Bar flexibility - grinder on the opposite side of the machine. And maybe one day, you'll get famous at throwdown pouring with the non-dominant hand.

I find ergonomics behind the bar crucial to being a barista. I can't emphasise enough how important it is to train on that topic. This is not only about preventing injuries and being less tired while working. Applying the basic ergonomics rules will make you also faster and more elegant. Like a chef who creates a beautiful dish in an effortless, elegant manner.

If you want additional information on ergonomics in the coffee industry and hospitality in general click links below:

Tamper Tantrum: The Ergonomics of Coffee Roasting

Sprudge: New Study Suggests Baristas Are At A Significant Risk For Injury

Sprudge: Barista Health Starts In The Feet

Tales Of The Cocktail: Stretch Yourself Before You Wreck Yourself: How Bartenders Can Prevent Common Workplace Injuries

Disclaimer: I do not benefit in any way from linking to particular products, the only purpose is to provide an example of great ergonomic designs

Title photo - Tasty Snaks

Back bend photo - Morten Rand-Hendriksen

My first competition

2016-12-11T10:18:00.000+00:00

As you know, for the past 2 months I was preparing for Cuptasters. That one is quite special to me. It was my first coffee competition ever.

Competition

Running a bit late for the briefing. Soon I've found out my round consisted of a slightly intimidating company. After that, my friend has rocked the first round setting bar with 7 in 2.29. Which remained the best score until the first 8.

In the meantime, I've saturated my palate on the cupping table on the festival.

Just before my round, I was a bit stressed, but not in a paralysing way. That has changed when the clock started ticking. I struggled to cup. Shaking hands is not what you want.

Mindlessly I picked the odd ones by some random hints of convergence. Which screwed me up. Trying to loosen stress I didn't focus on what I was tasting. Also, I didn't notice the unusually high temperature. I think I've even burnt my tongue a bit.

I managed my nerves in the middle and didn't pick odd one in 4th set. I slowed down. The cups were a bit cooler now. The rest of the table was easy (3 last triangulations were correct).

In total, I scored 4 in 6.33. Not bad at all. Above my average and close my best 5. At least half and it wasn't easy.

All coffees from the same roaster. Mostly the same origin in triangulation. Differences as subtle as farm, process, variety.

The competition is truly about sensory skills. You can't just guess. Psychological aspect (audience, photographers, timekeepers, judges) is a part of that, but nor more than 20%.

It's possible to zoom in, but I was quite distracted and full of nerves. When the timekeeper shouted 5 min has passed I found myself calculating how much is left and whether my pace is ok.

Temperature screwed me up as well. Usually, I cupped cooler cups. I could have made up for that with patience.

Next time I wouldn't rush. Get control over my nerves, keep a steady hand and be careful of temperature. Zoom in, ignore ambient.

All in all, I think I freaked out, but my result is absolutely satisfying. I wasn't last. More experienced people freaked out even more.

Overconfidence is a bad thing, I didn't have to pick straight away.

Well, next year.

As for now, I'm already a competitor. It's pretty amazing.

Tea Tasting

2016-10-02T18:18:00.000+01:00

If you're passionate about something, practice it in the most ridiculous way you can. My thing is sensory evaluation. Mostly taste and smell, but there's only so much you can do with coffee.

Black tea

Darjeeling 2nd flush - considered the champagne of teas. I really don't appreciate it that much. They say it's about the depth of flavour, floral aroma and muscatel character.

Whatever muscatel is, I probably would call it "Darjeeling flavour". Which raises a question about the definition of a flavour. For me, there's nothing worse than bringing down something to a "coffee flavour", as coffee itself has plenty of flavours. However, I might be as ignorant with that tea.

The truth is, even a flavour of blueberry can be deconstructed to smaller pieces. Which is shown in Sensory Lexicon:

The slightly dark, fruity, sweet, slightly sour, musty, dusty, floral aromatic associated with blueberry.

But as you can see, it comes down to association. In sensory science, flavour it's usually a matter of nothing but the association and common agreement.

Another highlight was the Chinese Yunnan. Region considered to be the birthplace of tea. Strong, smoky with a lingering aftertaste. Reminds me of Islay whisky. Way more smoky than any Yerba Mate I've ever had, even the famous Cruz De Malta.

Oolong

Typically a favourite one. Although I feel a bit tired of them. It's like drinking Geisha every week. There was one highlight though.

Eastern Beauty - dark oolong from Taiwan. Exceptional in a way no coffee professional would assume. Insects bite leaves before harvest, resulting in sweet-sour character. Natural process making it truly unique.

The acidity was actually perceivable. However, I still don't feel ok about the insects. How this could not be a nightmare?

Green and white

There's a lot to taste in green tea. Even though it's not in terms of particular flavours. Rather depth, the intensity of vegetal and savoury character.

But when it comes to white...

The Silver Needle is worth its price. Intensive aroma, big flavours, yet subtlety and sophistication. Geisha of teas.

Herbal teas

I've never thought it might be an interesting experience. Unfairly.

Chamomile has proven the flavour agreement. It's a mind-broadening experience to try something considered as "a flavour" and find another flavour in it. It was the first chamomile tea I truly enjoyed. Lots of apple and honey.

The same with Rooibos. Never before drank a good one, never before found cascara, rhubarb and honey characters in it. Wow.

Lemongrass was a big surprise. I didn't think about it as something to brew. However, you just can't help smiling while drinking it. Lemon intensity takes you to a place you've never been before.

The biggest takeaway for me is a flavour in flavour experience. The next time I taste chamomile in coffee, I'll think about its apple character.

Picture - A Girl With Tea, CC 2.0

Geisha

2016-09-03T18:32:00.000+01:00

Geisha is giving hard times to the coffee industry. It's expensive, hardly anyone knows where it really comes from and it's a "standard competing coffee".

Especially when it comes to the last one, the conversations lightens up. Recently, James Hoffman wrote a wonderful piece about Geisha in competition. And it's remarkable how many people have published something about Geisha since then.

Competition

It seems easy to compete with a varietal like this. It gets high scores on a cupping table. Has distinct flavour notes. And for years it is the Geisha winning in competitions.

But at the end of the day, it's not entirely fair to compare Geisha to Bourbon or any other.

I would love to see other coffees win competitions. It was exciting to see Dan Fellows winning UKBC with Heirloom from Ethiopia.

Same thing with Jem Challender and his exotic Javanica for Brewers Cup. For Worlds though, he switched to Geisha. Which again, is absolutely understandable from competitor's view.

There comes the idea of having several competitions for different varieties. One for Geisha, one for Caturra, Bourbon and so on. But I can't imagine this in practice. That's an extreme fragmentation, we would end up with only several people entering "a variety competition".

Restricting rules

Then there was a thought of banning Geisha. But let's say it would pass (which I don't believe in). Imagine the decrease in demand for Geisha. Baristas who prepare for competition, use a lot of coffee. Some people even consider it "Waste". Across the world, all these baristas add to a pretty nice percentage of general demand for Geisha. Especially considering not so high popularity in cafes and retail sales. I don't have any numbers, but I assume farmers would be affected by the ban.

Also, banning anything in the competition is against the idea of competing in the first place. That's where people experiment, come up with new ideas, share their knowledge. I'm for making the rules less strict. I love the idea of freeing milk beverages. Flat white is way cooler than Cappuccino, isn't it? The next big thing I want to see is letting baristas adjust machines - temperature, pressure and maybe even water.

Those parameters have been fixed for years. However, it is changing across the industry. I believe that through adjusting these variables baristas would be able to bring new life to different varieties.

Maybe it's that we need to see another variety to win. To set a precedent. To encourage people to use different coffee and increase its chances.

Low pressure on Black Eagle

2016-07-31T13:09:00.001+01:00

The most exciting thing in coffee at the moment is lowering pump pressure. The very act is no big science. But the research conducted by several professionals makes it science-backed.

Mat North, Michael Cameron, Matt Perger have inspired baristas all over the world. Including me. I wanted to give it a try.

But I work on Victoria Arduino Black Eagle. The machine with difficult access to its inside. The interactive menu allows you to change the pressure of the steam wand, but not the pump. Manual provides you with instruction to make a cappuccino, but there's nothing about the pump.

An insight

Black Eagle is the perfect choice for playing with variables. Pump pressure, temperature or extraction yield can be changed so easily it's a shame not to do it.

Benefits

Tastier espresso, higher consistency and respect from fellow baristas. And that's it.

Dialling in is about finding balance. You can find balance in uneven extraction. To exemplify, hitting 20% extraction with 9 bar pressure. But you will hate your espresso after a few times.

I got a coffee described as very sweet, with notes of lemon, peach, jasmine and caramel finish. The problem is, for 3 months of working with this coffee I never went past lemon and jasmine. I was dealing with an astringent, harsh, bitter and overwhelming aftertaste, doing my best to get the lemony one. "Has some sweetness" meant balanced extraction. The body was watery.

Until the day I lowered the pressure to 7 bars. Lemony start, followed by jasmine and sweet mango with a syrupy finish. The mouthfeel is round and creamy. The new espresso cuts through milk much better too.

In terms of consistency, I waste much fewer shots. Channelling still occurs but it's pretty rare. Making workflow on busy morning smoother.

Lower pressure helps especially with a guest coffee ground in EK43. No matter how tasty shots you can pull on EK, the grinder is not designed for espresso during busy times.

Photo - Niall Kennedy

Ethiopia Duromina

2016-07-17T12:04:00.000+01:00

Today I cupped away from home. Nothing new. But the first time I'm going to write about that cupping. Reason for that being I was alone.

Duromina is a relatively new thing. A cooperative of over 100 farmers to make better coffee. Jimma Zone has perfect climate for growing coffee, but it's always been low quality.

Now, as they've switched to washed processing due to Technoserve financing, their coffee is easily scoring over 90. Complex, clean and with a depth of flavours, it gets the best prices in Africa. The mill investment was repaid in only a year, instead of planned 4.

Details:

Origin: Ethiopia, Jimma Zone, Oromia
Varietal: Heirloom
Process: Washed, dried on African beds
Altitude: 1900-2000 masl
Roaster: Taylor Street Baristas
Score: 90.75

Cupping:

Fragrance: floral, lily, unusual for Ethiopia (maybe that how washed Ethiopia should smell)
Aroma: Very floral, with a distinct note of rose, not entirely uniform in terms of aroma

Flavour is like another level of Yirgacheffe. More delicate, no big flavours, but definitely big coffee. The depth and complexity got me lost. I have no reference for violet, but it seems to play a big role. Floral over fruity, but more interesting than jasmine and hibiscus.
However still fruity. Apricot, wild rose fruit, orange. Or maybe orange blossom. 65/35 for floral.

Acidity is beautiful. Generous but delicate. Not overpowering flavours and sweetness. Though again, not uniform from cup to cup.

Balanced like greatest Panamas, full-bodied like buttery Brazilians. Round, pleasant, silky, smooth. Yummy!

This coffee was scored at 90.75. I scored 90.5. It lost points mainly in aftertaste and uniformity. Probably some of these delicate flavours would linger a bit in the filter. But it shows the risk of flat espresso.
As far as I'm concerned cooperatives are not a great source of uniformity. Keep in mind over 100 farmers.

As for that, I cannot praise roaster enough. It would be a shame to hit another lemon/ginger/jasmine Geisha-like flavour profile as many roast Duromina that way. Frankly, I would use this coffee in the Brewers Cup.

Why 9?

2016-07-10T21:49:00.002+01:00

Lower pump pressure means 3 interesting things. More gentle water flow - less chance for channelling. More even saturation of the grounds. And less fines migration.

Considering the arguments above, how on earth everybody got stuck on 9 bars for so long?

History

The first coffee machines made "espresso" more like filter coffee. Successively the pressure was higher and higher. Which allowed for about 30s extraction of concentrated beverage known as espresso.

It's clear, that taste wasn't the critical factor. So, let's say the goal was to extract more. Understandable, but extraction percentage in relation to pump pressure is Gauss's graph. Therefore, as you increase pressure, you get higher extraction, but only to some point. After that, increasing pressure lowers extraction.

The reason for that is uneven extraction. The peak point of the graph depends on coffee used, grinder, baskets, distribution, tamping and hundreds other factors. The thing is, usually the peak point is around 8 bar with perfect technique (the one you do competing).

Café environment

Pulling 100 shots per hour, for 10 h on shift is a different case. You have to be consistent. And consistency derives from minimising unpredictability. Pump pressure is one of them.

Let's assume you have a decent tamp - firm, level and consistent. But everyone makes little mistakes from time to time. The tamp no. 793 of the day might be of lower quality. Lighter and not perfectly level. 9 bars would cruelly channel it into 22s shot (everyone is weighing shots, right?). Not acceptable. But 6 bars would gently go through the puck extracting servable coffee. The shot would not be perfect, but you wouldn't tell the difference by watching the shot.

The example above shows how lowering the pump pressure minimises an obstacle in achieving even extraction. Mitigating negative factors is a key to consistency. It also allows you to focus on different factors. Such as temperature or distribution.

Extraction

The ultimate factor is taste. Always. Taste is correlated more to evenness of extraction that extraction. The question is, can you taste uneven extraction?
Tasting this is like a reawakening. Once you get used to 6-7 bar pressure, pull a shot on 9-10 bar. Even if the shot doesn't seem to be channelled it's gonna be hell in your mouth.

Some critics may say, that getting used to 6 bars worsens your technique. Just like getting used to gravimetrics or volumetrics deteriorate to stop your shots manually. There's a hint of truth in that. However, stopping your shots manually has never been the best option (unless you really weigh the shot) - click here. Same with lower pressure. Getting ZERO chanelled shots is worth the game. We've gone far from tamping as hard as possible a while ago. Consistency is a major factor. And actually, you CAN tamp too hard - click here.