World of Tea

Tea Processing Chart

2012-04-25T17:34:10Z

Tea processing is the most important quantifier when determining or producing a tea type. Green tea, yellow tea, white tea, oolong tea, black tea and post-fermented teas all begin as fresh camellia sinensis leaves and go through different processing steps. While there are an infinite number of variations that result in an infinite number of tea styles, the same underlying processing methodologies largely define the tea’s type. It is important to note that other factors influence the quality of a tea type for example, certain cultivars of the tea plant produce hairier buds, a characteristic sought after in the production of bai hai yinzhen, or “white hair silver needle.” Furthermore, terroir and ultimately the level of care given to the tea plants and the leaves during picking and processing also attribute to the quality or lack thereof in a tea.

There are many tea processing charts that attempt to accurately depict the tea process, but many of them add unnecessary levels of complexity, or skip steps. The goal here was to depict very general processes that all tea styles within a particular type would fit into. I believe it is important to begin with an overly simplified and correct processing chart and add details later on.

Another fun thing to note, is that I made this so that it would be familiar to the discerning westerner — from a Chinese perspective, the last column “Post-Fermented Tea” would be labeled heicha or black tea. The second to last column, “Black Tea” would be labeled hongcha or red tea. That’s right. We have it all wrong here in the west — but that’s a different topic.

Feel free to challenge any part of this and to share it, just please give my blog attribution. If you find this interesting, be sure to check out my posts on some of these individual processing steps: withering, oxidation, and kill green.

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Tea Processing Chart by Tony Gebely is licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License.
Based on a work at worldoftea.org.

Killing the Green

2012-04-23T18:58:24Z

Have you ever wondered why Japanese green teas are so green? And why Chinese green teas are not as bright green, but are typically yellower? The reasoning lies in the processing steps for each tea and in particular the “kill-green” step of the processing some tea types. The term kill-green is derived from the Mandarin shaqing, which means “killing the green.”

Kill-green is also referred to as “de-enzyming” or “fixing” and is a process of tea manufacture used to halt the oxidative browning of tea leaves by denaturing the enzymes responsible for oxidation– polyphenol oxidase and peroxidase. Think of an apple, once it is sliced open, it quickly turns brown; however, the apples in apple pie are not brown because the heat used to bake the pie denatured the polyphenol oxidase and peroxidase in the apples and prevented enzymatic browning (same goes for potatoes, avocados, bananas, etc,).

In tea, the leaves must be heated to approximately 150 degrees Fahrenheit to halt oxidation. The longer it takes to heat the leaves to the temperature necessary for denaturing polyphenol oxidase and peroxidase, the more aromatics will develop. For example, green teas that are steamed reach this temperature more quickly than teas that are pan fired and as a result remain bright green and vegetal and lack a diverse aroma. Pan fired teas invoke what’s called the maillard reaction which is a form of non-enzymatic browning that produces toasty notes in a tea and finished tea leaves that are usually yellower in appearance. In general, most Chinese green teas are pan-fired (photo above), and most Japanese green teas are steamed (photo below). There are other methods for “killing the green” — sometimes an oven is used, or a bamboo basket over charcoal, while some teas are sun-dried and in this case, oxidation is halted not by heat, but by dehydration. The kill-green process of tea manufacture is commonly employed in the production of green, yellow, oolong, black tea when dried, and post-fermented teas.

I have one question though, if the “kill-green” processing step is actually preserving the green appearance of the leaves, why do we call it a term that means “killing the green?” My hunch is that this step not only preserves the green color of the tea leaves and prevents oxidation but it also puts to an end the grassy (or “green”) aroma that the leaves begin giving off once plucked, similar to how freshly cut grass gives off a strong scent. Can anyone confirm this?

Thoughts on American Tea Culture

2012-02-22T16:19:03Z

Or any culture for that matter. I was reading a translation by MarshalN of a Chinese blog post about snobbery in the tea world and it kind of went along with my thinking of late about tea culture here in America, where it seems like there are so many different groups with differing opinions and ideas that made up our “culture” here. I guess its a social “thing” that happens in a lot of niche industries. Let’s remove tea from the equation and talk about products in general — the masses (the majority) tend to cling to a product of lesser quality, and people break out into smaller factions surrounding the same product but a higher quality variant of it. Lets call the former group A and the latter group B. Group B begins to look at group A with disdain. From a quality perspective, group A’s version is usually lesser than B’s and usually group A paid less than group B for it. Going a bit deeper, when we look at the supply chain to group A and B, group A’s product is usually supplied by large companies and corporations, and group B’s product is usually supplied by smaller companies or sometimes group B will circumvent the middle man and go directly to the source for their product. Group A may just enjoy the product, while group B is obsessed by the product and tend to incorporate the product deeper into their lives, learning all they can about it and always seeking better quality product. Because the product means so much to group B, they are put off my people that don’t take it as seriously as them, or even those who broke out into another faction, for example those that like the product only for health reasons. When I say “put off” I mean not only that their opinions about the product differ, but also that they may not even tend to get along with the type of people in group A or another faction of group B aside from anything dealing with the product. Sorry I got to ranting here, but I always wonder how to bridge the gap, maybe it’s impossible. Maybe things like this will always happen.

What is Green Tea?

2012-04-23T18:22:37Z

The definition of green tea in it’s simplest and most generalized form is a tea that is made up of leaves that were prevented from oxidizing, shaped and then dried.

However, green teas are not unoxidized. No tea is truly unoxidized because tea leaves begin to slowly wither and oxidize the moment they are plucked, something that is unavoidable since hours may elapse from the time of picking to the time of processing. So let’s draw a line here and speak only of controlled processes. The most prevalent form of green tea production involves heating the leaves shortly after plucking (some green teas are allowed to wither for a short time before this), a controlled process that prevents the leaves from undergoing any additional oxidation. Heating the leaves denatures the enzymes in the leaves responsible for oxidative browning, preserving the green color of the leaves and halting the myriad of chemical reactions taking place as a result of oxidation. When heat is involved the process is called “kill-green” (from the Mandarin shaqing which means “killing the green”) and is typically done over a heated wok, in an oven, on a bamboo basket over charcoal, or by steam. With sun-dried green teas, oxidation is halted not by heat, but by dehydration.

Some green teas may be withered for several hours before oxidation is halted. In doing so, the vegetal characteristics of the tea are reduced and many new aromatic compounds are formed.

What is Oxidation?

2012-02-20T02:30:24Z

Oxidation is a chemical process that results in the browning of tea leaves and the production of flavor and aroma compounds in finished teas, oxidation is also responsible for the browning of some fruits and vegetables when they are cut open including potatoes, apples, and avocados. Controlled oxidation usually begins after tea leaves are rolled or macerated, two processes that break down the cell walls in tea leaves. Chemically speaking, oxidation occurs when the polyphenols in the cell’s vacuoles and the peroxidase in the cell’s peroxisomes come in contact with the polyphenol oxidase in the cell’s cytoplasm. The resulting reaction converts tea catechins into theaflavins and thearubigins. Theaflavins provide tea with its briskness and bright taste as well as its yellow color, and thearubigins provide tea with depth and body and its orange-brown color. This conversion of catechins to theaflavins and thearubigins means that the longer the oxidation, the lower the amount of catechins in the finished tea. Also, during oxidation chlorophylls are converted to pheophytin, a pigment that lends to the dark color of oxidized teas. Lipids, amino acids and carotenoids also degrade during oxidation to produce some of tea’s flavor and aroma volatile compounds. The oxidation of tea leaves is controlled by the tea master and requires moist, oxygen-rich air over time. Controlled oxidation is halted by drying the leaves, which renders the enzymes responsible for the reaction inoperable.

Oxidation is often incorrectly referred to as fermentation in the tea world. This is entirely false as fermentation involves the breakdown of chemicals by microorganisms. Until enough research was done, it was actually believed that bacterial fermentation was responsible for the browning of tea leaves and thus, the word “fermentation” was used, however, it is now a widely accepted fact that enzymatic oxidation is responsible for this browning. It is important to note that true bacterial fermentation does occur in the production of post-fermented teas, namely heicha and pu-erh. It is also important to note that there is no such thing as a “fully oxidized” tea; black tea is commonly referred to as a “fully oxidized” tea, but it is impossible to “fully oxidize” tea leaves unless they are first ground into a powder.

What is Withering?

2012-02-13T15:34:09Z

The moment a tea leaf is plucked from the tea plant, it begins to wither or wilt. The amount of this unavoidable, uncontrolled wither the leaves experience depends on how much time elapses from the time the leaves are plucked in the field until the leaves reach their destination and they are further processed and the quality of care that is given to them during this time. Withering is also a controlled process used in tea production. Tea producers use a balance of moisture and air-flow during a controlled wither to moderate the reduction of moisture in tea leaves until it reaches a desired level and to achieve other physical and chemical goals.

The physical goal of withering is to reduce the moisture content in the leaf, making the leaf flaccid and pliable, which prepares the leaf for shaping and rolling. The chemical goal of withering is to allow the aroma and flavor volatiles to develop in the leaves and for grassy aromas to be released. The longer the wither, the more aroma and flavor compounds develop in the leaves as many of the chemical compounds in tea degrade into volatile compounds. Since the leaves are cut off from their supply of energy, they also begin to break down their stored carbohydrates for use as energy. Loss of moisture causes cell walls to break down, initiating polyphenol oxidase and peroxidase activity – the reaction known as oxidation. Chlorophylls also begin to degrade at this time.

Controlling the withering process means closely monitoring humidity, temperature and air-flow over time. A controlled wither can occur outside with tea leaves laid out gently on bamboo mats in the shade, or indoors in troughs with forced air. The air may be heated to speed up the process. The withering process is complete once the tea has achieved its desired percentage of water-loss. Great care is also given to the density of the withering leaves to ensure that they wither evenly.

Photo source: http://www.flickr.com/photos/litrate/

Chicago Tea Tasting

2012-02-01T02:48:58Z

Had a great tea tasting for my company, Chicago Tea Garden in January. If you live in the Chicago area and would like to attend a tasting, please signup here. Thanks to Flickr user faraocious for taking these awesome photos!

view the whole set by foraocious here.

No Bullshit Tea Companies

2012-01-31T19:44:09Z

Someone recently asked me how many tea companies exist right now that have made a commitment to only sell pure tea. I didn’t have an answer, so I started searching, and with the help of my friends on Twitter and Reddit, I came up with the following list. The rules for the list: the tea company must sell tea in loose form only, and all of it must be unflavored. I let scented teas get by (the traditional ones), and I allowed companies with an herbal section on their website. Here’s what I have so far:

Hou De Asian Art & Fine Teas

Red Blossom Tea Company

Am I missing any? Feel free to let me know.

Tea: Not Just For Girls

2012-02-06T17:47:10Z

As children, we were indoctrinated with the idea that tea was a part of a tea party, an activity that girls took part in during childhood with friends, family, and stuffed animals. For many, tea was something given to us by our mothers when we were sick, or a drink consumed by our grandmothers during red hat lady get-togethers.

The reality in the tea industry today is quite opposite. While many tea cultures exist and the idea of having a “tea party” is very much alive today, many other rituals surrounding tea consumption are growing in popularity and are driving the growth of the tea industry. While there are many places in Chicago today where you can enjoy this spectacle of an afternoon tea with a spot of milk, some sugar, and light fare, the rich culture of tea is rooted elsewhere and several men in Chicago are helping to bring tea back to it’s roots.

What are these roots you ask? Tea has been consumed for thousands of years, true tea comes from the camellia sinensis plant, a plant native to China and transplanted elsewhere around the world. Tea originated in China and thus the Chinese were the harbingers of modern tea culture.

When prepared correctly, Chinese loose-leaf tea needs neither milk or sugar, it is best consumed alone and without complicated tea-ware. The Chinese invented the gaiwan a simple cup with a lid, the lid is tilted slightly to allow the tea to escape when it’s ready leaving the leaves behind. This method of tea steeping has been around for hundreds of years and tea aficionados regard it as the best way to prepare a tea infusion. You may not know it but Chicago is experiencing a male-led tea renaissance, this is not your grandmother’s tea, this is pure loose-leaf tea from the country that started the whole tea thing.

Meet the guys:

Chris Bourgea, Adagio Teas | http://www.adagio.com/stores/
Adagio just opened their third retail location in the Chicago area on State Street, Chris Bourgea has been working to meld Adagio’s online shopping experience into their new retail side of the business.

Dan Robertson: The Tea House | http://www.theteahouse.com
Dan has a storefront in Naperville and has also been running trips to tea plantations all over Asia for years.

Tony Gebely: Chicago Tea Garden | http://www.chicagoteagarden.com/
Tony has been selling tea online at Chicago Tea Garden and holding monthly tastings at his warehouse in West Town, his tea can also be found in several Chicago retail outlets. He has also been working on a book about tea.

Rod Markus: Rare Tea Cellar | http://rareteacellar.com/
Rod Markus has been selling his Rare Tea Cellar tea to Chicago’s top restaurants for several years now, chances are, if you’ve tried pu-erh at a restaurant in Chicago, it passed through his hands.

Bill Todd: Todd & Holland | http://www.todd-holland.com/
Bill Todd of Todd and Holland started his company in 1994 and has been selling at his retail location in Oak Park since, he buys direct from origin and has a great array of tea and teaware in his shop.

Shane Talbott: Talbott Teas | http://www.talbottteas.com/
Shane started Talbott teas and has been selling in the Oprah store and was recently featured on QVC, his tea was also featured as one of Oprah’s favorite things in 2011.

Why?

My customers are about 60% male, and men make up the majority of attendance at my tea tastings. Why guys? I think guys are fascinated by the history and culture of tea, and view tea as a hobby — seeking out the best of the best, matching tea with tea ware, using ancient steeping methods. It’s fun, it tastes great, and us guys love hobbies.

Smashing Pumpkins Frontman, Billy Corgan to Open Tea Shop in Chicago

2012-02-06T17:47:10Z

Smashing Pumpkins frontman, Billy Corgan announced today via his twitter account (@Billy) that he has plans to open a tea house on Chicago’s North Shore. Billy Corgan isn’t the first well known musician to jump into the tea business, electronic musician Moby opened a tea shop called “teany” in New York city in 2002.

The Tweet posted on 12/15/2011: