Serious Eats - The Food Lab

The Food Lab: How To Preserve Fresh Spring and Summer Produce

2013-05-20T19:15:00Z

It's time for another round of The Food Lab. Got a suggestion for an upcoming topic? Email Kenji here, and he'll do his best to answer your queries in a future post. Become a fan of The Food Lab on Facebook or follow it on Twitter for play-by-plays on future kitchen tests and recipe experiments.

I go a bit nuts every spring and summer when fresh produce is at its best. I end up buying things willy nilly, without much thought as to how I'm going to prepare, much less eat, all of it myself. After several valiant dinner parties and late night asparagus binges, I still find myself with far too much produce to even consider finishing everything before it starts to lose quality.

It's at times like this that it's important to know the basics of home preservation, and today I'm talking about how to treat vegetables and fruits to keep them as close as possible to their natural, raw, just-picked state for the long term.

This post doesn't even get into canning or pickling, both of which are excellent ways to preserve summer and spring produce. For more on that, check out our beginner's guide to canning, and any of the recipes from our "In A Pickle" column. No recipes this week, no boring stories about my wife or dogs, just a few quick tips on how to make the most of your spring and summer produce.

Tip #1: Cut Produce Small and Blanch Before Freezing

[Photographs: J. Kenji Lopez-Alt]

WHY IT WORKS:

Fruits and vegetables mostly consist of water trapped inside individual cells. As you freeze produce, this water will form ice crystals. Here's the thing: the slower water freezes, the larger the ice crystals it forms, and these large crystals can rupture cell walls, causing the produce to turn mushy. Thus, in order to maximize freshness, you need to maximize the rate at which your produce freezes.

It's for this very reason that small produce such as corn kernels or peas are considered to be among the best vegetables to freeze. Spreading your vegetables out on a wide tray with plenty of space in between them will also make for faster freezing.

But that's not the end of it: Vegetables also contain enzymes within their cells that can cause them to turn drab in color or to turn mushy faster. Normally these enzymes are safely locked away within the cells themselves. But as soon as those cells get ruptured—say, by the stresses of freezing and thawing—they'll begin to affect the final quality of the product.

Blanching vegetables in boiling water for one to three minutes will ensure that those enzymes are deactivated. Once blanched and frozen, your vegetables should stay bright green and crisp, even after thawing.

HOW TO DO IT:

Look for the smallest version of whatever produce you are planning on storing. This means petite peas, skinny green beans, and slender stalks of asparagus. Trim the vegetables. Larger vegetables like peppers, carrots, or beets should be cut into smaller cubes. Greens like kale and spinach should be stemmed.

Blanch the vegetables in a large pot of boiling salted water just until bright and tender-crisp, one to three minutes. Dry the vegetables very carefully on a baking sheet or plate lined with several layers of paper towels (for leafy greens, squeeze them in a clean kitchen towel to remove excess moisture).

Spread the vegetables on a rimmed baking sheet and freeze them thoroughly before transferring them to zipper-lock freezer bags or cryovack-style bags for long-term storage.

Tip #2: Double Bag It

WHY IT WORKS:

Air is the enemy of frozen produce. Ice in frozen foods can sublimate directly into water vapor, escaping into the air and producing freezer burn. In order to prevent this, you want to keep your food in the most air-tight environment possible.

Regular plastic bags may seem impermeable, but they can actually breathe air and vapor through their surfaces at a very slow rate. Thicker freezer bags or cryovack-style bags are better, but even they aren't completely air-proof.

HOW TO DO IT:

Place frozen produce in a freezer bag and squeeze out as much air as possible. Seal the bag. Place it inside a second freezer bag and seal again. Alternatively, pack your goods in thick, cryovack-style vacuum seal bags.

Tip #3: Don't Wait Until the Last Minute

WHY IT WORKS:

Many vegetables—particularly asparagus, peas, corn, and fava beans—lose sweetness very rapidly once they're picked, as their sugars convert into starches. There is a noticeable difference in sweetness between an ear of corn that was taken directly off the stalk and one that's been in storage for even a day.

To make the best of sweet spring and summer produce, you need to blanch and freeze it as soon as possible after purchase to lock its sugars in place and prevent the formation of excess starch.

HOW TO DO IT:

Buy asparagus, peas, corn, and fava beans direct from the farmer in the early morning, if possible. Most farmer's markets should offer picked-that-morning produce during the spring and summer. Once purchased, bring it home as soon as possible, then immediately wash, prepare, blanch, and freeze it.

Tip #4: Cook Delicate Vegetables and Freeze Flat

[Photograph: Josh Bousel]

WHY IT WORKS:

Some vegetables—particularly watery or delicate vegetables like tomatoes, summer squash, zucchini, and eggplant—don't freeze well, turning translucent, mushy, and generally unattractive. For such vegetables, it's usually a better idea to cook them before freezing. Cooked vegetables have already had their cell structure broken down and some of their water content removed, so the post-frozen-then-thawed results can actually end up quite similar to the freshly-made preparations.

Freezing the resultant preparations in a flat shape—such as lying in a zipper-lock bag—will maximize surface area, making for faster freezing and thawing. When frozen flat, I can defrost last summer's zucchini soup for two in about 5 minutes.

HOW TO DO IT:

Cook the vegetable according to your favorite liquid-based recipe. For instance, tomatoes can be cooked into Marinara Sauce, zucchini can be cooked into Provençal Lentil-Zucchini Soup or along with eggplant, onion, and tomato, into Easy Summer Ratatouille.

Once the vegetables are prepared, pack the soup, sauce, or other preparation into heavy-duty freezer bags or cryovack-style vacuum seal bags. Carefully remove as much air as possible, then place the bags flat on a rimmed baking sheet and freeze until solid. Once frozen, the bags can be stacked in the freezer for space-efficient storage.

To thaw, the bags can be placed directly in a pot of warm water or under warm running tap water. Once it returns to a liquid form, transfer the contents directly to a pot and reheat.

Tip #5: Wash Berries in Hot Water

WHY IT WORKS:

In the past, I'd heard that washing berries before storage is a bad idea, as they may absorb excess water that causes them to spoil faster. After washing various types of berries (including strawberries, raspberries, and blackberries), I found that this is not actually the case. Sure, they'll pick up a bit of moisture, but it's entirely a surface effect. With careful drying—say, by spinning them in a salad spinner lined with paper towels—they weigh exactly the same after washing as they did beforehand.* What's more, washed berries stay mold-free for several days longer than their unwashed counterparts.

*Incidentally, the same is true for mushrooms as well—go ahead and wash them.

Want to extend their lifespan even further? Wash them in hot water. The idea may seem a little strange at first (doesn't heat promote decomposition?), but it turns out that berries are much tougher than we think. As Harold McGee pointed out in a 2009 New York Times article, because berries are used to sitting out in bright sunlight, they can actually withstand temperatures that are hot enough to cook a steak to medium rare.

The mold spores and bacteria on their surfaces, however, are much more sensitive to the heat and get destroyed.

HOW TO DO IT:

For short-term storage, fill a bowl with hot tap water. It should register about 120 to 130°F on an instant-read thermometer—just hot enough that it's uncomfortable to dip your hand into. Add the berries and submerge them for about 30 seconds. Drain carefully in a colander, then gently spin them dry in a salad spinner that's been lined with a triple layer of paper towels.

Store the berries in a breathable container, such as a plastic bag or deli container with holes punched in it.

Alternatively, berries can be frozen for future use. Unlike with vegetables, blanching can ruin the texture of berries, so it's best to freeze them raw. Place them on a rimmed baking sheet and freeze until solid, then place the solid berries in a double freezer bag for long term storage. Frozen berries will never have the texture of fresh, but they can be used in cooked preparations, for smoothies, or for eating straight from the freezer.

About the author: J. Kenji Lopez-Alt is the Chief Creative Officer of Serious Eats where he likes to explore the science of home cooking in his weekly column The Food Lab. You can follow him at @thefoodlab on Twitter, or at The Food Lab on Facebook.

Ask The Food Lab: Is It OK To Probe My Meat?

2013-05-16T12:30:00Z

[Illustration: Robyn Lee; photographs: J. Kenji López-Alt]

"Is it OK to probe my meat with a thermometer while it's cooking?"

I've heard that probing meats to test temperatures can be bad because you creates holes that juice leaks out of. Is this true? I've always used the leave in thermometers that stay in and I don't remove it until my meat has rested. Is this an unnecessary step? What if you have to test multiple times, will that cause a difference?

—Sent by canihazpotato

In case you haven't noticed, I'm a very strong proponent of using a thermometer when you cook meat. Forget the poke test or the cake tester or any other such method that's based more on machismo or restaurant service speed than accuracy. For a home cook, the absolute best method to guarantee that your meat comes out cooked perfectly every time is to use a thermometer. The Thermapen is my thermometer of choice. It's pricey, but it'll pay for itself after the first prime rib roast that you don't overcook.

But this does bring up a good question: doesn't probing that meat cause juices to leak out? Doesn't every grill master tell you not to use a fork when you flip your meat to keep that seal on the exterior?

Here's the good news: those grill masters are wrong. There is no seal on the outside of a steak any more than there is on the outside of a hamburger or a meatball. Moisture from the interior can escape just as easily whether that exterior is punctured like a balloon or not.

On the other hand, what you do have to worry about is whether or not you're breaking apart muscle fibrils, the sheath-like containers in which meat juice actually is stored.

See, if you look at a cross section of a steak through a microscope, it resembles a bunch of bundled up telephone wires all running parallel to each other. As a steak cooks, the cables tighten up, squeezing out their contents.

The fact is, the tip of a probe thermometer or a fork is simply too dull to actually puncture or cut those fibrils. The most you'll do is rip them apart a tiny bit. This may result in a miniscule amount of juice loss, but the difference is far below the threshold of human detectability and pales in comparison to the extra moisture loss if you, say, overcook that steak by a few degrees.

Indeed, that's why instruments like a jaccard—a multi-bladed tool designed to tear apart muscle fibrils before cooking—can tenderize meat without causing it to lose excess moisture. Heck, if meat could really be punctured like a ballon, you'd expect a steak that's been treated with a jaccard to weep juice as soon as it starts cooking, when in fact, it cooks almost exactly the same as an un-punctured steak.

Even cutting a steak with a knife to peek inside for doneness is not going to make a significant impact on its eating qualities, though it's difficult to judge doneness by appearance (hot juices can make a steak appear more rare than it really is).

What about leave-in thermometer?

Leave-in thermometers are a different story. I am not a fan of them for two major reasons.

First off, they are constructed of metal, and metal happens to be a far better conductor of heat than, say, meat, fat, or bone. This means that when you are cooking a roast in the oven for a long time heat energy will travel through the probe and into the meat faster than anywhere else in the roast. You end up with an artificially hot zone right around the probe, which can lead to false-high readings of up to a few degrees.

Not only that, but it's nearly impossible to pinpoint exactly where the coolest part of the roast (the part you want to take the temperature of) is going to end up until after it's done cooking, again leading to false-high readings with a leave-in probe.

This is not the worst thing in the world—it'll ensure that you get an early warning signal. But when that leave-in probe hits the desired finished temperature, make sure to take the actual temperature of the meat in several other areas. Chances are it's still got a few more minutes of cooking left.

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The Food Lab: How To Make Tacos Al Pastor At Home

2013-05-06T18:40:00Z

VIEW SLIDESHOW: The Food Lab: How To Make Tacos Al Pastor At Home

[Photographs: J. Kenji Lopez-Alt]

I have been working on this recipe for longer than any other recipe I've ever worked on. The number of times I've told Erin, "Sure, go ahead and put it on the schedule for next week," only to swap it out at the last minute because I wasn't happy with the results is a number higher than I care to count. But at long last, I'm pretty darn pleased with the results.

It all started about a year and a half ago when the good folks at Columbus Food Adventures took me on a whirlwind taco tour of Columbus, Ohio, which, believe it or not, has some of the finest taco trucks in the country. Particularly impressive were the tacos al pastor from Taqueria Los Guachos.

There, in true al pastor form, the taqueras marinate thin, thin slices of pork shoulder in a mixture of chilies and aromatics colored bright red with achiote. The slices are then stacked onto a vertical skewer, forming a large, bell-shaped trompo (spinning top), which gets topped with an onion and pineapple, and slowly rotates in front of a vertical grill. If there's a reason it resembles shawarma or doner kebab, it's because the concept was first introduced to Mexico by Lebanese immigrants.

As the trompo spins, it slowly cooks, the fat from the pork shoulder dripping out and across the surface of the meat, basting it as it crisps. As each outer layer of meat crisps up, the taquera shaves it off with a sharp knife, catching it in a soft corn tortilla before topping it with a bit of the roasted pineapple, salsa, and cilantro and onions. It's really glorious stuff. Juicy and crisp with a deep chili flavor tempered by sweet roasted pineapple.

It doesn't really get much smokiness, per se—the fire is usually a simple gas fire—but it does get a little bit of singed char. Those in the know will ask for theirs to be cooked up extra-crisp on the plancha after it's been sliced. The results are almost bacon-like in their succulence.

The question is: Can we replicate this at home?

Meaty Matters

The problems with such an endeavor are immediately obvious. First off, there are the basics. What's the best meat to use? How do I slice it so thin? How about the marinade? Is there an ideal time to marinate for? Then there's the issue of actually cooking the stuff. Can we replicate a vertical rotisserie? Is there some other viable option that would work?

I started off by addressing the meat. Normally, al pastor is made with boneless pork shoulder sliced super, super thin. If you are lucky enough to live near a Mexican meat market, you can probably find it right at the meat counter. The rest of us need to do a bit more work. I decided to test pork shoulder along with a couple of easy-to-find alternatives.

This is a pork shoulder:

It's a large, unwieldy hunk of meat with a couple of strangely shaped bones in the middle and a whole lot of rind. Unless you have years of experience butchering, cleaning it up without mangling it is not an easy task. So what advantages does it offer?

For one thing, it's packed with flavor. With meat, the more an animal uses a particular set of muscles, the more flavor they'll acquire. Pork shoulders are used extensively throughout the pig's life, rendering them extremely porky and full of fat and connective tissue that breaks down into rich, unctuous gelatin as it slow-roasts. But for the pork to be tender, it must be sliced thin and must be slow cooked.

This kind of slicing is not easy to do with the equipment you've got at home, which brings us to...

Pork sirloin. Cut from the pig's back towards the hind legs (the hams), sirloin is far easier to work with (it's easy to find a boneless sirloin roast), is relatively easy to slice, and is more tender than shoulder. These are all good things. The problem is that it lacks fat and connective tissue, making it prone to drying as it cooks.

The final option I tried was pork belly:

The fattiest cut of all (it's what bacon is made out of), pork belly is packed with flavor and connective tissue. It can be a little difficult to butcher properly—you have to remove the rind and any small rib bones remaining—but it's relatively easy to slice thin, and—I thought—should produce extremely juicy tacos.

I tried slicing each cut of meat (against the grain, of course!) into thin sheets, but couldn't get them as thin as needed for proper al pastor.

Instead, I resorted to pounding them flat by laying them in an opened up heavy duty plastic bag and smashing them repeatedly with the bottom of a skillet.

The resultant pieces of meat were as wide as I wanted, with the added advantage of having a small amount of tenderization occur as well.

To cook the meat, I started with a basic working marinade recipe and grilled the slices directly rather than trying to stack them and slice them—all I was interested in at this point was the flavor and texture of each cut.

Turns out that belly is fatty alright. A bit too fatty for this. Shoulder was great, but sirloin was so much easier to butcher. For the sake of ease, I decided to go with a combination of sirloin and belly.They complement each other perfectly when it comes to flavor and fattiness. Belly can be a bit tough to slice properly, but for now it'd have to do.

Marination Revelations

The flavor base for al pastor is pretty well defined. The marinade is essentially an adobo—a sauce made with chilies, garlic, and vinegar, along with whatever other aromatics you'd like.

Using fresh dried chilies is essential. They should be pliable and flexible. If your chilies are crackly, crumbly, or dry, it's because they're old and most likely, all their flavor has dissipated along with their moisture. Do yourself a solid, throw out those old chilies, and get some new ones. I found that a combination of rich and raisin-y ancho chilies along with bright guajillo chilies was a great complement to the pork. I toast them in a dry saucepan before soaking them in chicken broth

Achiote is a mildly earthy, ever-so-slightly bitter spice with a distinctive bright red color. It comes in paste, pellet, and powdered forms. I personally find the powder easiest to store and work with, though any form will do.

To get the most flavor out of it, toasting in oil is essential. For my marinade, I toast the achiote powder along with some powdered cumin and Mexican oregano.

If you are a regular reader of this column, you'd know that marinades are largely a surface treatment. That is, they don't penetrate particularly far into a piece of meat; it's on the order of a millimeter or two per day, and it gets considerably slower the deeper into the meat it gets. Point is, in most applications, there's not much reason to marinate beyond a few hours.

But there are exceptions to this rule, and they mostly involve salt.

Salt is special. See, rather than simply flavoring meat by working itself in between muscle fibers, it actually alters the structure of meat, primarily by causing certain parts of the protein myosin to become dissolvable in water.

What does this accomplish? Well, by dissolving myosin, muscle structure is greatly loosened, allowing it to retain more moisture (this is the principle behind brining), and more importantly in this case, it allows proteins between muscle groups to cross-link, causing them to stick to each other.

This is why, for instance, sausages get a nice bouncy, snappy texture, and why if you remove the salt from one, it becomes crumbly and dry (see here for more info on salting and making sausages, and here for some deeper scientific info on the process of salting meat.

This is all well and good, but why is it important to tacos al pastor?

The thing is, in a well made trompo of meat, as the carver slices meat off of it, it should come away in coherent slices, not crumbles, and it should have an almost cured, bacon-like texture—moist, juicy, and crisp as opposed to crumbly or chalky—two sure signs that there is some salting action going on. To get to this stage, you need about 1 to 2% salt per unit weight of meat, and at least a few hours of marination time.

With a good flavorful marinade, you could just grill the meat and call it a day—many respectable and delicious recipes do just that—but that's not what I'm after here. What I want is the real deal. Cured texture, crispy bits, shaved slices and all.

This requires a bit of tinkering.

Getting In Shape

My very first thought was why don't I just build a trompo in miniature?

I tried layering my marinated meat into an empty quart-sized deli container before allowing it to rest overnight (in order for proteins to cross-link and for the meat to cure slightly). I then stuck a skewer right down the middle, inverted the whole thing, topped it off with a pineapple, and built a base out of the pineapple bottom into which the skewer head could rest, allowing the whole thing to stand upright under its own support.

So far so good.

To cook it, I set up the ring from my Weber Gourmet System Wok Grate. By placing coals around the perimeter of the coal grate, as well as directly on top of the wok grate, I was able to create a vertical heating system that cooked the pork and pineapple from all sides simultaneously.

I gotta say, it looked pretty bad ass, and surprisingly, it worked relatively well, albeit with a ton of fiddling, searing my hands to maneuver sticky pork juice-covered pineapple, adding more coals after realizing it was going to take far longer than expected, entertaining guests while their pork cooked, etc.

In short, it worked, but it wasn't fun or easy.

Loafing Around

Here's one thing to remember: cooking on a vertical spit may look like a fast cooking method—The outer layers of meat are searing and crisping after all, right?—but in reality, it's a two-stage slow-then-fast cooking process. While the taquero is busy slicing off the exterior layers of the trompo, the layers within are meanwhile slow-cooking, causing the meat to break down and tenderize. This is, in conjunction with thin slicing and curing, are why even a tough cut like shoulder can come out tender and juicy when cooked. It's only after the inner layers of meat are exposed that they fast-cook.

So why not just separate the two phases of cooking? I returned to a method I employed when making Greek-American Lamb Gyros: pack the meat into a loaf pan before cooking. By then slow-roasting it in the oven (or on the cool side of a grill), I could get the meat as tender as I liked it before slicing it and finishing it off under the broiler or in a skillet.

The method worked like a charm, especially if you let the cooked meat rest in the fridge until chilled before slicing it.

For the record, here's what insufficiently salted meat looks like when you try and slice it:

And here's how it looks if it's been salted properly.

See the difference?

The only little thorn left in my side was the pork belly, which to be frank, is not easy to come by or to slice properly. The easy solution? Just use bacon. Bacon is already cured, already thin-sliced, and once combined with the marinated meat, blends nicely into the background, adding fatty richness and juiciness without overpowering with its smoky flavor.

As the pastor-loaf cooks, it exudes a ton of juices and fat. This is OK.

The fat is the ideal medium for re-crisping the sliced meat in a skillet (and for painting onto a pineapple before roasting it), and the juices can be added to the crisped meat to add some flavor and extra moisture back to the mix.*

*Some folks speculate the the pineapple added to the top of a trompo of al pastor will tenderize the meat as it cooks. While it's true that pineapples contain an enzyme that will break down meat protein, in the case of al pastor, it does not have this effect. The enzyme deactivates due to heat long before it can get a chance to actually break down any protein, particularly in the inner layers of meat, which don't get exposed to any dripping pineapple juice until long after the pineapple has been fully cooked. The effect of the pineapple is for flavor only, thus it can be added after the fact with no real difference.

I know I've said this, but this recipe took a long time and a whole slew of failures before I finally got it right. I'd estimate in the multiple dozens of failures over the last two years or so. But when something finally works out, it makes the whole process worth it, failures and all.

I know that the dogs would agree, and not just because they got to eat most of the failures.

Pretty, right?

The one issue you may have is that, well, the recipe does take a long time. A night to cure. Another night after roasting for it to re-set and become sliceable. That said, the actual active time is remarkably low, and most of it can be done in advance. Once the pastor-loaf is cooked, it can rest in the fridge for a few days before slicing and crisping to serve, which means that if you're planning a dinner party, it only requires a few minutes of work on the day-of to get the best tacos al pastor you'll find outside of a real taqueria.

For me, that ain't a bad trade-off.

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Click here for the full recipe for Real Tacos Al Pastor! »

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Ask the Food Lab: Can I Start Pasta In Cold Water?

2013-05-02T18:45:00Z

Can you start cooking pasta in cold water? If not, why?

—Sent by Robis

If you're a long-time reader of The Food Lab, you might remember an article I wrote that addresses this very question a few years back. I feel it's important enough to warrant a recap.

It's a great question, and one that I've got a personal history with. One of my very first jobs in a restaurant was as a cook at No. 9 Park, a modern Italian/French restaurant in Boston. I spent a good nine months or so working the pasta station, where it was drilled into my head that the water in the pasta machine better be boiling before I put the pasta into it or it won't cook properly and will stick together all mush-like, creating a disturbance in the forza as if millions of Italian grandmothers suddenly cried out in terror and were suddenly silenced.

I never questioned it because it wasn't my place to. It wasn't until about a decade later, when I saw how my not-yet-wife cooks her pasta, that I started realizing that maybe the rule wasn't so hard and fast as it was made out to be. Her method? Cover pasta with cold water in a relatively small pot. Put it over a burner. Stir it a few times as it heats up, then leave it alone.

And it comes out perfectly fine.

Why is this? It's because cooking pasta is actually a two-phase process: Hydration and cooking. Normally, the two go hand in hand—the pasta absorbs water as it cooks. But it doesn't have to be.

Turns out that whether you start with hot or cold water, pasta will still absorb just about the same amount. To prove this, I cooked a few batches of pasta side-by-side in various amounts of water, and starting at various temperatures. No matter how I did it, the pasta all ended up soaking about 75 percent its dry weight in water, and the pastas were indistinguishable from each other in a taste test.

Indeed, the pasta cooked in a small volume of water had a distinct advantage: the pasta water contains more starch, making it more effective at tightening up a sauce and getting that sauce to cling to the cooked pasta.

The fastest, most energy-efficient way I know to cook dry pasta is to place it in a medium saucepan, cover it with salted water by an inch or two, place it over a burner set on high and heat it, stirring every few minutes. Once it comes to a boil, put a lid on the pot and turn the heat to the lowest setting. Even if it loses its boil, the pasta will still continue to cook so long as it's kept above 180°F or so. Follow the back of the box for timing, starting the timer as soon as it comes to a boil, and subtracting a minute or two from the recommended time.

Want some more cool info? Read on!

Does A Large Pot Boil Faster?

Want to hear something even more interesting? Folks will occasionally say that "using a large volume of water will help the water come back to a boil more quickly."

Back up a minute there, because you know what? This is untrue. In fact, in most real world cases, the exact opposite is the case.

But how is this so? Doesn't adding a fixed amount of pasta to a small pot cause the temperature in that post to drop more than it does in a large pot? Therefore doesn't the large pot come back to a boil more quickly? Let's examine the ideal scenario first.

You have two pots of water. One has 1 quart of water, the other has 1 gallon—four times as much. Both are sitting on top of identical burners and are at a full, 212°F boil. Now add a cup of dry pasta to each one. Because the pasta is at room temperature, it will cause the temperature of the water in each pot to drop, and the water in the quart-sized pot will drop four times more than the one in the gallon-sized pot.

Ah ha!, you say. If the temperature fell four times lower in the small pot, it must take four times longer for it to come back up to a boil!

The problem with this line of reasoning is that it doesn't take into account the fact that it takes four times less energy to raise a quart of water by one degree as it does to raise a gallon of water. Since a burner puts out energy at a constant fixed rate, the small pot, which needs to cover a temperature gap four times as great as the large pot, serendipitously also heats up four times faster. This means that the two pots of water return to a boil at the exact same time!*

* For the record, it's also the same amount of energy and time required to bring a cup of dry pasta from room temperature to 212°F.

In the real world, the "big pots boil faster" camp is even more wrong. See, the larger a pot, the greater its surface area. And the greater the surface area of a hot body, the more rapidly it can lose heat to the outside environment. How does this affect heating?

Let's say your burners put out heat energy at a very respectable 10,000 Btu. Meanwhile, your small pot might be losing heat energy to the air in the kitchen at, say, 1,000 Btu, giving you a net energy input of 9,000 Btu. A large pot, on the other hand, will lose heat more rapidly due to its larger surface area. Let's say, 2,000 Btu. Your burner is still exactly the same, putting out 10,000 Btu, which means that with a large pot, the net energy input is only 8,000 Btu.

Thus, a large pot will actually return to a boil more slowly than a small pot.**

** This doesn't even take into account the heat loss from evaporation, which again compounds the case against large pots.

Surprised?

Take it To The Limit: Soaking Pasta

The folks over at Ideas In Food have written about "1 minute pasta." The trick? Soak dried pasta in water until it is fully hydrated. Once that's done, all you've got to do is cook the pasta—say, by tossing it in hot sauce—and it comes out as if it had been cooked and hydrated all at the same time. The beauty in this method is that by pre-soaking pasta and having it sitting in your fridge, you don't have to bring a pot of water to a boil every time you want to eat it. Pasta prep becomes almost immediate.

It's how I generally cook my pasta these days: start the pasta soaking while I prepare a sauce or other ingredients. By the time the sauce is hot and ready, the pasta is hydrated, and all I've got to do is drop it in the sauce and let it finish cooking. Easy!

I also use this method whenever I'm putting together a lasagna, like this Creamy Spinach and Mushroom version.

The Exceptions

There are times when you do want to start with a large pot of already-boiling water. The first is when cooking fresh pasta. Because fresh pasta is made with eggs, if you don't start it in boiling water, it won't set properly, causing it to turn mushy or worse, disintegrate as it cooks.

The second exception is with long, skinny pasta shapes like spaghetti or fettucini. Because they stack together so easily, it's more likely than with other pasta shapes that they will stick together. As the pasta heats and absorbs moisture, starches on its surface gelatinize, becoming sticky, If the strands are stuck together when this happens, they'll fuse together permanently, especially in a smaller pot where you have less room to maneuver them.

So to cook long, skinny pasta, you've got two real options. First is the traditional method: A large pot of salted boiling water gives you plenty of room to move the pasta around, limiting the risk of it sticking together.

Your other option is to use the pre-soak method. Because starch needs to be heated to gel properly, soaking pasta in cold water will allow you to hydrate it without worrying about it sticking together. Once it's fully hydrated, you've just got to finish it off in your sauce and you're ready to serve.

For a more detailed answer to this question, check out my old article A New Way To Cook Pasta.

Got a question for The Food Lab?

Email your questions to AskTheFoodLab@seriouseats.com, and please include your Serious Eats user name in your email. All questions will be read, though unfortunately not all can be answered.

The Food Lab Rapido: Cheesy Grits with Spring Vegetables

2013-05-02T13:15:00Z

[Photographs: J. Kenji Lopez-Alt]

Last year my good friend BraveTart sent me a bag of grits from Weisenberger Mill, just down the road from her place in Lexington, Kentucky. Growing up in New York and Boston, grits were never exactly a thing in my household. I don't think my mom even made polenta, let alone true Southern-style grits. My only exposure to them was at family reunions where my more southern-inflected cousins and aunts would cook up trays of cheesy grits with Jimmy Dean breakfast sausage cooked right in. That was some fine breakfasting there.

But dammmmn if I haven't developed a taste for them since then. Even instant grits can be alright provided you add enough butter and cheese to them to lend them some flavor (the same can be said for instant mashed potatoes). But if you want the real deal, you need to start with coarse-ground corn meal and cook it the old fashioned way. Low, low heat, with plenty of attention to stirring.

The thing with grits is that they'll clump up on you faster than you can say "Where'd I leave the butter?", and once clumped, it's nearly impossible to unclump them. The best grits—the ones that have been stirred constantly from beginning to end—should be rich, tender, and creamy, but not gluey or stodgy.

Some folks like to cook their grits in plain old water, but I prefer the creamier, richer consistency you get when you cook them with a combination of milk and water. This, of course, is enhanced by the copious amounts of cheese and butter I stir into it at the end. Any nice cheese will do, but I use a combination of super sharp cheddar (I like the clothbound stuff made by Cabot in Vermont), along with some parmesan for a bit of extra funkiness.

Like polenta, grits practically beg to be topped with a saucy accompaniment, something that'll ooze extra flavor into it. This is exceedingly easy to do in the spring, when sweet, tender green vegetables are at their finest. I use a mix of asparagus, fava beans, English peas, and snap peas. The best way to cook them is to blanch them in salted boiling water first, then to finish them off by glazing them with butter and herbs in a pan. This two stage process helps preserve their sweet flavor and crunch, while adding some extra flavor from the herbs, carried by the buttery glaze. A touch of lemon zest and juice adds bright freshness.

If you can get your hands on some good dried or fresh wild mushrooms, they also make a great addition to the grits. I used morels picked by a buddy of mine out in Michigan. He dries them and sends them to me. I reconstistute them in water and use them throughout the year. Because of their thinness and irregular shape, dried morels hold up remarkably well (better than most dried mushrooms).

A poached egg tops the thing off, adding its rich golden yolk to enhance the saucy vegetables.

What's that? You hate poaching eggs? We got you covered. With this technique, your eggs will come out perfectly every time.

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Cheesy Grits with Spring Vegetables »

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The Food Lab Mini: Crispy Taco Shells Made of Cheese? Yes!

2013-04-22T19:45:00Z

[Photographs: J. Kenji Lopez-Alt]

Last week I was lamenting on Twitter that despite having spent over a week trying out what are supposedly the very best breakfast taco joints in Texas, I still hadn't tasted one that I felt was even good, let alone worthy of the kind of culinary praise that they regularly get. For me it's the overcooked eggs that ruin 'em.

Hearing @mattyglesias talk about Texas reminded me of something I need to get off my chest: Breakfast tacos are severely overrated.

— J. Kenji López-Alt (@TheFoodLab) April 17, 2013

Anyhow, this is neither the time nor place to get into a battle on the merits of breakfast tacos, and I'm sure we can all agree on at least one thing: as a concept they are unassailable. We just differ in how we like them to be executed.

Aside from the obvious fracas, that tweet precipitated a very useful conversation when the folks geniuses over at Ideas In Food suggested that perhaps I'd like my tacos better with a different delivery mechanism. Namely, a crispy fried cheese shell.

In their 2011 post about "Italian Tacos", they fry a slice of provolone cheese on the griddle until it's a deep golden brown, then fold it over a rolling pin, tuile-style and let it harden into the shape of a little crispy taco shell before stuffing it with fried mortadella and pickled peppers. It looks delicious.

As they rightfully say, it's essentially Italian frico curled into a taco shell shape. I'm simultaneously excited and frightened at what would happen if Taco Bell and Doritos hear about this one and decide to make Doritos Locos Tacos Doritos with an all-cheese chip coated in orange cheese powder. Excited, frightened, and slightly disgusted.

Now honestly, I've got absolutely nothing against the fresh, well-made flour tortillas that breakfast tacos commonly come served in. I actually like them a great deal. But the idea of stuffing some creamy, soft-cooked eggs into a crisp cheese shell seemed so darn appealing to me, that very night I decided to try it out.

If you're only making a couple of frico-taco shells, the easiest way to do it is to place a greased ring mold on top of a cast iron or non-stick skillet, then fill it up with a very thin layer of grated cheese. I used Parmesan, though any sort of sharp cheese will work.

The key is to use very gentle heat so that the cheese melts and browns evenly. As soon as it starts to melt, retrive that ring mold, using a small spatula or spoon to pick off any bits of cheese that stick to it.

Once your cheese is frying, don't turn your back on it for a second or it will burn. It waits until you are looking away, all sneaky-like.

As soon as it's a pale golden brown and has stopped bubbling, it's ready to lift and fold. Use a thin spatula to make sure that it releases easily from the pan.

If you want to make a larger batch, it can be done in the oven. Just line a baking sheet with a silicone liner (parchment paper will work as well), lay down cheese using a ring mold, then bake it at 400°F until the circles are browned.

Shaping the shells is easy; the only key is to work relatively fast, because they harden within 5 to 10 seconds of being removed from the pan. Ideas in Food used a sheet of parchment paper draped over a rolling pin to shape their shells. I found the parchment unnecessary—a thick-handled wooden spoon did the trick just fine.

Once your shells are made, they'll stay crisp indefinitely until you're ready to fill them, but once filled, make sure to serve them immediately or they'll start to soften up, particularly with very moist fillings.

Soft scrambled eggs mixed with Mexican crema (or crème fraîche) along with a sprinkle of crisply-fried chorizo, basic salsa verde, and a bit of queso cotija is excellent. The crisp shells give way to the creamy egg center, and the flavor of eggs and Parmesan is unquestionably delicious.

I stuffed another batch with esquites, a salad of charred corn seasoned with queso cotija, scallions, cilantro, and chilies with a squeeze of lime.

The only other trick with these guys is that the shells are so delicate that you have to make them tiny. Like, 2 1/2-inch wide, taco-for-ants sized. Too big and they'll crack under the weight of their own fillings. They are also cumbersome to fold and shape when you make them large.

I can't wait until my next fancy-pants party so I can make a few dozen of these to serve as hors d'oeuvres.

If the goal of my original tweet was to find some breakfast tacos worth eating, I didn't exactly get there, but I'm pretty happy with the destination I ended up in anyway.

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Crispy All-Cheese Taco Shells »

Soft Scrambled Egg and Chorizo in Crispy All-Cheese Taco Shells »

Charred Corn Tacos in Crispy All-Cheese Taco Shells »

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The Food Lab Turbo: How To Make The Best Grilled Cheese Sandwich

2013-04-18T21:30:00Z

VIEW SLIDESHOW: The Food Lab Turbo: How To Make The Best Grilled Cheese Sandwich

[Photographs: J. Kenji Lopez-Alt]

A grilled cheese is a grilled cheese, right? I mean, it's the first meal that most of us learn how to cook at home by ourselves. It's the perfect midnight snack or soup-dipper. It's great for kids but is never turned down by an adult. It's salty, gooey, crisp, buttery, and comforting in all the right ways.

But there's grilled cheese, then there's GRILLED CHEESE. When you're faced with a perfect grilled cheese, globules of cheese slowly oozing out of the edges, a pure, even golden-brown face suffused deeply with butter, you know even before you bite into it if the experience is going to be transcendental. It's the way you can feel the butter in the bread, but it doesn't leave your fingers greasy (at least not too greasy). The way the crust is crisp but flexes ever-so-slightly so that you know there is a layer of tender crumb waiting underneath before you hit the molten core. The way the aroma—that buttery, brown aroma—curls up into your nose just before you take the first bite.

And that's all before you even get that glorious cocktail of textures and fat into your mouth.

So how do you get there? What are the secrets to the best grilled cheese?

We've learned a thing or two about it over the years. Here are our best tips and our favorite recipe.

The Cheese

A grilled cheese doesn't work with just any old cheese. You've got to have a cheese with just the right melting characteristics. Dry, crumbly, fresh cheeses like goat cheese won't melt properly. Ditto for overly aged cheeses like a parmesan or hard Pecorino. For the true classic flavor, nothing is better than ultra-gooey, not-too-sharp American cheese. As we found in our American Cheese taste test, so long as you aren't going for vegan cheese slices, any old American cheese will do. I personally use Kraft Deli Deluxe Singles.

If you want to get fancy, a young cheddar, Swiss-style cheeses like Gruyère (or its French cousin Comté), or young Italian and French cheeses like young Fontina, Tallegio, or Brie go well, too. As long as it melts, it's got a place in our sandwiches.

If you do like the flavor of a non-melter, it's acceptable to treat it like another topping—that is, pair it with a cheese that does melt. A mozzarella and feta combo makes a fine sandwich, as does a Fontina and Parmigiano, for instance.

When at all possible, it's best to go with sliced cheese as opposed to grated. It is easier to distribute evenly, is less prone to making odd holes in the interior of your sandwich, and melts better (many of the best melting cheeses are too soft to grate effectively).

The Bread

Aside from necessarily being sliced, the only other rule here is that it can't be too hole-y (or your cheese will drip out), and it can't be sliced too thick (lest your cheese won't melt). White bread and American is what many of us grew up on, but if you want to go fancier, feel free to use a nice hand-sliced Italian ciabatta, a good sourdough, or a French boule. Grilled cheese is a great way to use up day-old bread, as the grilling process will resuscitate it a bit.

I use either Pepperidge Farm or Arnold white sliced sandwich bread for my grilled cheese. It's got a bit more substance than Wonderbread and its ilk, but not so much that it becomes tough. If you can get your hands on it, Japanese-style shokupan will make the finest grilled cheese you've ever had.

The Method

Low and slow is the way to go with grilled cheese. Not so slow that the bread dehydrates, but slow enough that you can achieve a thick, even, golden brown crust on each side before the sandwich starts to burn. This means using a heavy pan. The easiest is to use a non-stick pan with an an aluminum core, which will distribute heat evenly and allows you to swirl your sandwich around, achieving more even cooking. A cast iron skillet that's been preheated for about 10 minutes over low/medium-low heat will work as well.

Make sure to use enough butter so that it really forms a good layer of contact with the bread. Butter does more than add fat and flavor—it provides a medium through which heat is distributed. If you don't use enough butter, you'll get spotty browning. Also, do not allow your butter to burn or brown. The browning should be slow browning of the proteins and sugars in the bread, not the milk solids in the butter.

The best method I've ever seen for making a perfect grilled cheese comes from Adam Kuban. His secret? Grill the bread on both sides. That's right. Grill two slices of bread in butter, flip'em over so that the browned sides are facing up, add your cheese, and close your sandwich so that the cheese is sandwiched between the browned surfaces. Not only will this get you better tasting bread infused with more butter, but it'll also give your cheese a head start on getting extra-melty.

I only ever use unsalted butter at home (it's more versatile), but I always felt there was something missing from my grilled cheese sandwiches until I realized that without the salt added from salted butter, that childhood flavor just wasn't there. Seasoning the cooked sandwich with a pinch of kosher salt solves that problem nicely.

Stay tuned over the next couple weeks for a dozen grilled cheese variations.

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Check out our step-by-step slideshow here! »
Get the recipe for Serious Eats' Grilled Cheese Sandwiches here! »

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Video: The Food Lab's Foolproof Hollandaise in 2 Minutes

2013-04-18T20:00:00Z

[Video: Jessica Leibowitz]

I'd read about hollandaise, I'd eaten hollandaise, I'd even tried to make hollandaise as a very young cook, but it wasn't until I actually had to make it for paying customers that I really got the hang of it. Somehow, making a couple quarts of it every single day for four months will drill it into your head.

Traditional hollandaise, made by emulsifying melted butter into egg yolks and lemon juice, is notoriously difficult to make. You not only have to take the same care in its construction as you take for oil-in-egg-yolk mayonnaise (getting clarified butter and lemon juice to peacefully coexist is like the Middle East peace talks of the culinary world), but you also have to deal with the fickle nature of hot eggs and butter. Cook the eggs too much and you get scrambled eggs. Don't cook them enough, and your sauce won't thicken. Allow your sauce to cool as you make it, and your butterfat will crystallize, breaking your sauce.

But there's a super easy way to do it at home that requires no whisking, is completely foolproof, and produces a hollandaise that's indistinguishable from one made using traditional methods.

It stems from the realization that rather than heating your eggs then adding relatively cool butter, you can just as easily heat your butter and add it to relatively cool eggs, cooking them as the emulsion forms. It's a sort of backwards way to think about hollandaise, but there's no denying it works.

You'll notice that the construction method—using a cup and a hand blender to form a vortex that gradually pulls down fat—is very similar to my 2-Minute Mayonnaise. That's because mayonnaise and hollandaise are kissing cousins, nearly identical in structure.

Check out the video below to see precisely how it's done, then go back and check out our video on foolproof poached eggs. With the two methods combined, my brunch has never been easier or more consistent.

Some folks may comment on my use of full butter as opposed to clarified. I find that the milk solids that form the upper layer of melted butter do not impact the sauce at all, while the liquid and milk solid phase at the bottom of melted butter can be poured selectively to thin the sauce to whatever consistency you desire. Usually, I just dump the whole thing in and nobody is the wiser.

Head here for the full recipe! »

Transcript

Here's the full transcript, in case you're stuck at work or perhaps hiding behind enemy lines.

If there's one recipe that strikes fear into the hearts of cooks, one recipe that has a reputation for being difficult, it's hollandaise sauce.

Like mayonnaise, hollandaise is a fat-in-water emulsion. Normally, when you combine fat and water, the fat separates and forms a greasy layer that floats on top. The key to a successful emulsion is to break that fat up into individual droplets so small that they disperse evenly in your liquid.

Now traditionally, you'd this by whisking egg yolks and lemon juice over a double boiler until they're hot and frothy, then slooooowly whisking in butter in a thin, steady stream. The butter breaks into minute droplets, while the egg yolk acts as an emulsifier, helping to keep those droplets dispersed, as well as thickening the sauce. What you get is a creamy, smooth sauce with a rich texture and mild flavor, perfect for topping eggs, fish, or vegetables.

But there are a lot of ways things can go wrong. If you don't whisk fast enough or pour in your butter too fast it'll turn greasy and broken. Don't cook the eggs enough and it won't thicken properly. If you cook the eggs too much and you'll end up with clumpy, greasy, scrambled eggs.

The reality is that if you're going to learn how to do it the traditional way, the road to perfect hollandaise is going to be paved in broken sauces.

But here's the good news: there's an alternative method that is completely foolproof, produces a hollandaise that is every bit as good as the traditional version, and takes about one minute start to finish. All you need is a small pot, a glass measuring cup, and a hand blender with a cup that just barely fits its head.

We start by combining a couple of egg yolks in the base of the blender cup along with a teaspoon of lemon juice, a teaspoon of water, and a pinch of salt. Next, we heat up a stick of butter on the stovetop until it is completely melted and bubbling. It should register around 220°F on an instant-read thermometer. Pour that butter into the measuring cup.

Now all we do is stick the head of the hand blender at the bottom of the jar, start it running, and slowly pour in the butter. As the hot butter hits they eggs, they start to cook. By the time all the hot butter has been added about 30 seconds later, you've got rich, smooth, creamy, hollandaise sauce that's completely indistinguishable from sauce made using the traditional whisk method.

Hollandaise will be at its best right when you make it, but If you want to store it, your best bet is to keep it in a small, lidded pot in a warm spot near your stove and make sure you use it within a couple hours.

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Ask the Food Lab: Do I Really Need To Reduce Wine Separately?

2013-04-11T19:15:00Z

"Do I really need to reduce wine separately?"

I was just watching an America's Test Kitchen episode in which they said to reduce a wine/port/red wine vinegar mixture till syrupy, then add chicken stock. I couldn't help wondering why that's any better than adding the chicken stock initially and reducing the whole thing. Water loss is water loss, right? To the same point, recipes are forever distinguishing between simmering sauces slowly versus rapidly reducing them. What's the difference?

—Sent by RobC_

Reduction—the process of simmering a liquid to concentrate its color, aroma, and flavor—may seem at first like an extremely simple process whereby you're just removing water, but in fact, it's a bit more complicated than that, as any chef, distiller, or chemist, for that matter, can tell you.

There are a couple of important processes going on during reduction. The first is yes, water loss. Water molecules are held together in relatively tight formation when in liquid form, but even so, surface molecules have a tendency to get a bit overexcited and jump off into the atmosphere. This happens very slowly at lower temperature (say, a puddle drying up on a warm day), and rather rapidly at hotter temperature (the steam coming off the top of a hot tub, for instance). Eventually, when the water gets hot enough*, it'll escape very energetically indeed as it simmers or boils away.

*Specifically, when the vapor pressure of the water's surface is equal to or greater than atmospheric pressure

But here's the deal: when simmering, water is not the only thing escaping. Ever notice how when you come home to a pot of sauce simmering on the stovetop or perhaps a beautiful pot roast braising in the oven, your entire home smells of it?

Guess what: if those flavorful aromatic compounds are reaching your nose, it means they are leaving the pot.

The smaller and lighter those compounds are, the more likely they are to jump out of the pot with the evaporating water and float off into the air.

Vigorous boiling can exacerbate this effect as it agitates the molecules even harder.

Think of a pot of stock as a ball pit with dozens of kids playing in it. The balls represent small, light water molecules, while the kids (who come in all shapes and sizes) represent various flavorful molecules. Now stick this ball pit on the back of a dump truck driving down a bumpy road.

Drive that truck slowly and it'll minimize bumps. The small plastic balls will bounce a bit and escape at a relatively low rate. Drive slowly enough, and you'll even be able to reduce the number of plastic balls without losing any kids. This is what it's like to reduce a stock very, very slowly.

Speed that truck up a bit and you'll start losing your balls faster, along with a few of the skinnier kids. They fall along the side of the road, never to re-enter the ball pit.

Go faster still and you may end up losing all of the light, skinny kids, leaving you with a few balls, along with all the larger kids. You may have gotten to your destination faster, but it's at the cost of diversity and complexity.

A sauce reduced quickly will be flatter-tasting and less flavorful than a sauce reduced slowly. Try it side by side with two pots of stock or two pots of wine and you will see.

Moral: When reducing any liquid for a sauce, it's best to go low and slow.

Reducing Alcohol

With wine, it gets even more complicated, as you've got another factor to contend with: alcohol.

We all know that ethanol has a lower boiling point than water, so you may think that by heating an alcohol and water mix to the boiling point of alcohol, only the alcohol will be escaping. This is not in fact the case, and it's one of the factors that makes distillation complicated. When simmering an alcohol and water mix, the vapor coming off will be a mixture of alcohol and water, even if the liquid hasn't yet reached the boiling point of pure water.

This is because water molecules like to stick to each other, as do alcohol molecules. When you've got 100% water in a pot, the molecules are tightly aligned with each other and stuck tight, making it tough to separate them and cause them to jump off into the atmosphere. Add some alcohol to that mix, and the average distance between water molecules grows—thus their hold on each other is weaker, making it easier for them to evaporate. The same holds for alcohol molecules.

That's why it's nearly impossible to remove the alcohol content from a sauce or stew by simmering it on the stovetop. By the time the alcohol has been removed, most of the water will be evaporated as well.*

*It's for this reason that collecting, condensing, and re-distilling the vapor that comes off an alcohol/water mixture can only get you so far. At a certain point (about 95.6% alcohol and 4.4% water), the alcohol and water form what's known as a positive azeotrope, a mixture whose boiling point is lower than either of its constituents. It boils at 78.2°C, lower than pure alcohol (78.4°C) or pure water (100°C). The vapor coming off of it is also at the same proportion as the liquid itself, meaning that no matter how long you boil it, you'll never alter its alcohol content.**

**This is why if you work in a biology or chemistry lab, it's all right to drink the 95% ethanol on a late night, but stay away from the 98% stuff, which is distilled with benzene to remove those extra few percentage points of water.

Reducing the wine separately, then diluting the resulting reduction, is a far more efficient way of minimizing the overall final alcohol content of the dish than attempting to reduce the alcohol after combining it with the remaining liquids.

For instance, say I start with 500ml of wine with an alcohol content of 10%. I reduce it on the stovetop by half, leaving me with 250ml of reduced wine that now has an alcohol content of, say, 4% (the actual content will vary depending on the exact conditions I performed the reduction under). When I subsequently add 500ml of stock to that mix for a final volume of 750ml, I end up with a final alcohol content of 1.3%.

If, on the other hand, I start by combining 500ml wine with 500ml of stock (resulting in a liquid with 5% alcohol) and reduce it by 33% to get to a final volume of 750ml, I end up with an alcohol content of around 3% (give or take)—more than twice as high as if I had reduced it separately at the start.

Moral: If you want to end up with a reasonable amount of alcohol in your final dish, reduce wine or liquor it separately before adding your stock. (Around 1% alcohol is a good range for most sauces made with booze).

Reducing Vegetable-based Sauces

Reducing fresh vegetable-based sauces, like a tomato sauce, is another kettle of fish. In these sauces, enzymatic action comes into play. Tomatoes and other vegetables naturally contain enzymes that will break down pectin, the carbohydrate glue that holds cell walls together. Cook these raw purees at a relatively low temperature (under 180°F or so), and the enzymes will break down enough molecules into smaller bits that the sauce will thicken up pretty considerably. But the thickening is short lived. As you continue to heat the sauce, molecules continue to break down to a point where they cannot thicken at all, creating a watery sauce.

In his indispensable food science encyclopedia On Food and Cooking, Harold McGee states that for a vegetable-based sauce, rather than starting at a low simmer, "if instead the raw puree is cooked quickly close to the boil," enzymes are deactivated before they get the chance to break down pectin, which in its whole form is a more efficient thickener. "The result is a thicker sauce that requires less subsequent reduction."

Moral: For the best fresh tomato sauces, heat the tomatoes rapidly at the start to deactivate enzymes, then reduce the heat to a bare simmer to concentrate flavor. Note that as canned tomatoes have already been processed with heat, their enzymes have already been deactivated—it's totally fine to cook a canned tomato sauce at a low simmer in order to reduce while minimizing flavor loss.

Got a question for The Food Lab?

Email your questions to AskTheFoodLab@seriouseats.com, and please include your Serious Eats user name in your email. All questions will be read, though unfortunately not all can be answered.

Ask the Food Lab: Do I Need To Preheat My Oil?

2013-04-04T18:45:00Z

It's time for another round of The Food Lab. Got a suggestion for an upcoming topic? Email Kenji , and he'll do his best to answer your queries in a future post. Become a fan of The Food Lab on Facebook or follow it on Twitter for play-by-plays on future kitchen tests and recipe experiments.

[Doodle: Robyn Lee; other photographs: J. Kenji López-Alt]

Do I Need To Preheat My Oil?

A lot of recipes instruct you to heat oil to a certain point (till shimmering, smoking, or just an unspecified 'Heat oil over medium heat') before adding the first ingredient, say onions. Does it matter if you wait for the oil to heat, or could you just as well throw the other ingredients in with the cold oil?

—Sent by Tombolo

The answer is: it depends.

There are two reasons you'd want to heat your oil. The first is that it can prevent foods from sticking.

See, raw proteins can interact with metal on an actual molecular level. It doesn't just stick by "getting stuck in the pores and microscopic cracks" as some people hypothesize. Even on a perfectly smooth, polished surface with no cracks/imperfections whatsoever, meat will still stick as proteins form molecular bonds with the metal.

How does preheating prevent this? The thing is, only raw proteins will form this bond. Heat causes proteins to fold in on themselves, or even to break down and form all new compounds. Once in their folded or rearranged form, they no longer stick. So the goal is to get the meat to cook before it even comes into contact with the metal by heating oil hot enough that it can cook the meat in the time it takes for it to pass from the air, through the film of oil, and into the pan.

With a hot enough pan and the right material, just the heat of the air and the radiant heat of the pan itself will be enough to do this, but the oil helps. Another alternative would be to pre-sear meats by, say, hitting them with a blowtorch before adding them to a skillet.

That's why most recipes that call for searing meat will advise you to heat the oil in the pan to the point where it starts shimmering or even lightly smoking.

The second effect that preheating has on oil is that it alters the way in which heat travels through the ingredient being cooked. Basically, the hotter the pan, the larger the temperature differential will be between the outer layers of the ingredient and the center. So controlling the starting temperature of your oil can help you control the final product.

For example, with a steak, you want the exterior to be blasted by heat in order to precipitate the Maillard reactions—the series of chemical reactions that cause meat to brown and develop flavors—so you want to get your pan and oil as hot as possible before adding it.

On the other hand, if you want to, say, soften up some onions or garlic without browning them, you don't want to preheat the oil too much or you'll end up caramelizing or burning the exterior of the onion pieces before they get a chance to soften and cook through.

You may be asking why you can't preheat the pan, then add the oil, and the answer is that you can, technically. The problem is that without oil in it, it's very difficult to determine how hot a pan actually is. Starting with oil in the pan is a good indicator of how hot the pan is. We know that shimmering oil is hotter than pooled oil (it starts shimmering at around 300 to 400°F), while smoking oil is hotter still (depending on the type of oil, this begins at around 450 to 500°F). The oil is a built-in temperature indicator.

There are times when it's perfectly fine to start with both your oil and your other ingredients in a pan before you ever even apply heat, specifically when the food being cooked is unlikely to stick, and a slow, even cook is what you are looking for. Sautéed onions are a prime example of this. Even when a recipe suggests heating the oil first, you can rest assured that you probably won't taste any difference in the end.

Got a Question for The Food Lab?

Email your questions to AskTheFoodLab@seriouseats.com, and please include your Serious Eats user name in your email. All questions will be read, though unfortunately not all can be answered.

The Food Lab: The Crabbiest Crab Cakes

2013-04-02T14:30:10Z

VIEW SLIDESHOW: The Food Lab: The Crabbiest Crab Cakes

[Photographs: J. Kenji Lopez-Alt]

After only two months on the wagon, my wife has renounced her once purely vegetarian ways. The food that made her come back to the sentient side of the food chain? Crab cakes.

Now before I go on, I trust that you Serious Eaters will not be giving my wife any lip about a lack of will power. I don't want anyone asking her how the desire for tasty crustacean comestibles somehow trumped her health and ethics, or asking her if there are any other promises she's made that she plans on breaking in the future. We'll have none of that, ok?

Thing is, I don't blame her. I love crab with an undying passion. Sweet and tender, with the aroma of the ocean and a tenderness that lobster only aspires to. And in cake form—warm and tender with a buttery aroma and just a touch of tartar sauce, it's even better. At least, is should be better.

The sad truth is that most crab cakes stink. Literally. The vast majority out there are made with canned, pasteurized crab meat which instantly takes them out of "sweet and succulent" territory and into "fishy and please god take that smell away from me" land.

Then we've got those crab cakes that are more cake than crab, packed with pasty binders and bland fillers. Or you may run into the kind that's so heavily coated in bread crumbs that they may as well be called vaguely-crab-scented-croquettes.

If my wife is going to break her vows, it had damn well better be for the best possible crab cakes out there. I made it my mission to make them.

Getting Good Crab

The first problem with most crab cakes is the crab itself. It's easy to find picked blue crab meat (the only crab variety for crab cakes!) in pasteurized tubs, but the stuff is fishy smelling, wet, and already overcooked. Without good crab to start with, you can't make good crab cakes.

What you want to look for is fresh-picked lump or jumbo lump crab meat. Crab season on the eastern seaboard runs from spring through late fall, and on-season, it's relatively easy to find crab at a good seafood retailer, or to order it online from a number of sources. Off season, it's not quite so easy, but a good retailer should be able to order you some from South American sources.

Your best bet? Just hope that you don't get a hankering for crab cakes in the off season.

Binder Blues

Tackling the issue of binders in crab cakes is not easy. Unlike, say, ground beef, fresh-picked crab meat does not want to bind with itself. You can rub it and knead it and press it together all you want and all you've succeeded in doing is turning it into pasty mush that still doesn't want to stick together. What you need is some form of un-coagulated protein to make every stick together. The classic choice is egg, which not only adds protein, but also adds moisture and some degree of leavening power.

But a simple egg and crab mixture is impossible loose, nearly impossible to form into cakes that stay in shape—they simply sag and spread out like a deflated jellyfish.

Saggy cake

In order to solve this problem you generally add some sort of starch binder. The more of these binders you add, the easier it is to form cakes and maneuver them in a pan, but the worse the finished texture of the dish.

Low-binder crab cakes easily fall apart.

Binders are usually applied in one of two methods. The first is to add eggs and flour along with some mayonnaise creating an almost batter-like consistency. The mayonnaise adds fat to the lean crab meat, as well as a bit of acidic tang.

Crab Batter

As the cakes cook, the batter sets up, while the eggs help leaven it slightly. You end up with a crab cake that is vaguely pancake or fritter-like in texture. Not terrible, but not what I'm going for.

Alternatively, you can add eggs and breadcrumbs in some form, whether they're regular or panko breadcrumbs, or crushed up saltines or oyster crackers.

Crab Paste

This method is preferable to me, as the breadcrumbs create a more irregular texture in the cake, as well as adding some level of flavor on their own, but even better would be to be able to go with no extra starchy binders at all.

Eliminating starchy binders and instead going with a strict egg-and-mayo base can work if you're willing to have your cakes look more like lumps and if you're ok with only broiling them as opposed to sauteeing in butter. It's better than no solution, but still I think we can do better than compromise.

The Freezer Aisle

Back when I worked at Toro, a Spanish tapas restaurant in Boston (and soon to be New York), I learned a neat little trick for making cod croquettes with impossibly tender innards: Make a very soft, barely-bound filling, then partially freeze it before coating in bread crumbs and frying. The crumbs form a seal that keep the filling from falling apart as they fry, resulting in a croquette with a crisp exterior and interior that literally melts in your mouth.

Would a similar technique work for my crab cakes?

Pasty Patties

I tried it, forming patties bound with just a touch of mayo and an egg, freezing them, then breading them and shallow frying in some butter and oil in a cast iron skillet.

The crab cakes were great—the best yet—but the thick coating of bread crumbs was distracting. For my next attempt, I made a new set of patties, this time shaping them into neater, tighter cakes by forming them inside ring molds (I also tried forming them in rings made of aluminum foil, which worked just as well) before freezing them.

After frozen, I popped them out and breaded just one side in bread crumbs. That way, I figured, I'd get the best of both worlds: the bread crumbs will add some crunch and keep the cake from completely falling apart as it cooks, while the rest of the cake will be naked crab.

Frozen Fun

Everything seemed to be going fine as I slipped the breaded cakes into the skillet bread-side-down, but as they slowly thawed, they gradually fell apart. I was left with lose crab meat sauteed in butter along with an intact disk of fried breadcrumbs. I tossed it with pasta and called it dinner, then got back to work.

My final plan: Why bother removing the aluminum foil rings from the cakes after freezing them? I made a new batch of crab mixture, froze it in foil rings, then breaded one side of the cakes without removing the foil before slipping it into the hot butter in the skillet.

Only after the crab cakes cooked long enough to hold themselves together did I then carefully peel off the foil. I held my breath as I watched them cook, then mentally* high-fived myself when they did.

Foiled Again!

That is, they did until I tried to flip them. Even with a gentle metal fish spatula, turning them without breaking them apart turned out to be a tough task. Not impossible, but tough.

*ok, physically

Butter Up!

The solution turned out to be using a hybrid cooking method: Starting the crab cakes in a hot skillet with butter to crisp up the bread crumb layer, carefully peeling off the foil, then spooning some of the browned butter over the top of the crab cakes to lubricate them and baste them before popping the whole thing under the broiler.

Golden Delicious

With the aid of the browned butter, the broiled side of the crab cakes brown beautifully, while the bread crumb layer gets ultra-crisp as it continues to cook as the tops brown.

Crisp and Crunchy

The cakes that emerge from the oven are everything I want in a crab cake. A crisp, golden layer of crunch that doesn't overwhelm the crab underneath, and a crab filling that is really made of crab—absolutely no starchy fillers at all. All of this with the buttery, golden crust you get from the best naked-pan-fried crab cakes.

One Last Trick

The only issue with the recipe is that if you plan on making more than a few cakes, it can be a bit tedious to for all of the little foil rings and stuff them with crab. Mush more efficient is to use the method that Heston Blumenthal uses to form his hamburger patties: Form the crab mixture into a large log wrapped in aluminum foil, partially freeze the whole thing, then slice it into disks with a knife.

Slice'em All

After slicing, the disks stay nicely intact with perfectly fitted foil liners, ready to bread and fry.

Nothin' but Crab

Crab cakes good enough to at least tempt the staunchest of vegetarians and meatatarians alike.

And what's that you say? You've never had Eggs Chesapeake?

Crabs Hollandaise

In that case, may I suggest that you get your butt into the kitchen immediately and find a solution for that problem? Here's a foolproof way to poach eggs to get you started.

What are you waiting for? I said go!

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Get the recipe for The Crabbiest Crab Cakes here »
See a full step-by-step slideshow here »

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Video: Alton Brown and The Food Lab Play With Chicken

2013-03-29T13:45:59Z

A few months back Alton Brown stopped by the office to chat with us about such diverse topics as how to write a recipe for an omelette, his top five pieces of kitchen equipment, and even the future of recipe writing. Now chatting is all well and good, but I'm not going to pass up on the opportunity to actually cook with the man who made me want to do what I do today.

To make it exciting, we grabbed the first raw ingredient we could find—a whole, head-on chicken from the Chinese supermarket around the corner—and placed a bet on it.

The game: we took both breasts off the chicken and cooked them to 155°F. One was cooked by starting it in a hot skillet, the other was cooked starting cold. Which one would lose more moisture?

Check out the video to find out.

I'm not exactly sure what makes this particular experiment "great" or even really an experiment, per se. More like moderately poorly controlled, trivially important kitchen futzing if you want to know the truth. But either way, I had a heck of a fun time doing it; it's a rare thing to get to meet one of your personal heroes, much less to cook a chicken with him. Hopefully you'll get a kick out of watching it.

Watch the Video!

[Videography: Jessica Leibowitz; Doodles: Robyn Lee]

Alton Brown: "No they don't, Kenji. They don't think about that all. And it kills me..." (high-pitched laugh) So let's say that we're going to cook two chicken breast pieces to the exact same internal temperature, but start them at completely different times, so that we have one that goes in hot and cooks for a shorter amount of time versus the one that... you know what, we should weigh them before they go in as well.

So we got 99 grams and 111 grams, one's going to go into a cool pan, and let's pick a final temperature.

J. Kenji Lopez-Alt: Let me cool this pan quickly because it's already smoking.
AB: So we notice that he likes to live dangerously by pouring water directly into the hot pan of oil so that it aerosolizes, causing third-degree burns. Duly noted! Okay, what kind of surface temperature do you want to see?
JLKA: 400?
AB: At least.
JKLA: 450?
AB: So it's okay to put your hands on the chicken and then stick em back in the salt. Okay, also noted. Good sanitation procedures.
JKLA: What's going to live in the salt?
AB: Nothing's going to live in the salt at all. I'm just giving you crap. I think the interesting thing's going to be if we cook them both to the same doneness, if we pick a spot center mass, and we decide on a final temperature, 155, is going to be the comparison of weight of moisture loss. I'm going to hypothesize that there's going to be more moisture loss out of chicken breast B.
JKLA: Right, because we're cooking it at a higher temperature the whole time.
AB: Surface to mass ratio. Reading 161 center mass. #2 is of course way down from that. Da da da da. 78 grams.
JKLA: I'd say it's About 78%, given that we started with basically 100. 99.
AB: But it's not exactly. I mean, if you wanna play all loosey goosey with the facts, that's your business. 78.78% okay. This is primary research, man. We're in Harold McGee territory. Are we close to the same temperature?
JKLA: Yep. It's too bad they don't make chicken breasts in completely uniform sizes.
AB: We're working on it...we're working on it. 84.68%. I was guessing that the piece that went into the colder pan would, because of its reduced surface area, maybe retain more moisture, but indeed there is a relationship between time and moisture loss. So the piece that went into the hot pan stayed moister.

In order to quantify anything that's going on with your food, you've got to have measurements.
JKLA: Yes.
AB: Now ideally, we would have been measuring time. We didn't. But, not only did we weigh things, we weighed things digitally, in metric.
JKLA: In metric, yes.
AB: And we took careful temperatures, not only of the pan, but of the food, so we've got three data points. But this is still a pretty big trend. 84.68% vs 78.78%.
JKLA: Yeah, that's not insignificant.
AB: Lunch! Lunch is up. This is enough to feed like six girls from New York.
JKLA: Well, it's impossible to say without bias, because I know that this one lost more moisture, but...
AB: I note it no difference whatsoever.
JKLA: No?
AB: So what we've learned is that it freaking doesn't matter.
JKLA: Start with a good bird and don't mess it up?
AB: Here's the other thing. Food tastes better when you're hungry. And meat is more tender when you're hungry because you produce more saliva. As Cervantes said, hunger is the best sauce.

More 'Chewing the Fat' Videos

Alton Brown's 5 Essential Pieces of Kitchen Equipment »
Alton Brown on Future of Recipe Writing »
Alton Brown on Why His Thanksgiving Turkey Recipe Is Perfect »
Alton Brown on Writing an Omelette Recipe »

Ask The Food Lab: Can I Remove Heat by Removing Fat?

2013-03-28T21:30:00Z

"Can I remove heat by removing fat?"

Since capsaicin is fat-soluble, by skimming the fat from my chili, am I effectively removing all the heat from it?

—Sent by The MKT

It's no secret that capsaicin, the hydrophobic* compound that gives chili peppers their heat is most concentrated in the fleshy white membranes that surround the seeds of a chili**, so by removing those sections before cooking, you can significantly tame the heat that'll end up in your finished dish. But what about in a dish that's already finished? Since capsaicin is fat-soluble, would taking the fat out of a finished dish remove all the heat as well?

*Hydrophobic things are things that hate water but love fat, sort of like my Boston terrier Yuba.

**At least, it should be no secret, and if it is, then you need to find some more interesting things to keep from other people.

The short answer is no, it won't. Why not?

How Capsaicin Works

First, let's take a look at how capsaicin works. Capsaicin is an organic compound very similar in shape to vanillin (the molecule that gives vanilla its characteristic aroma). Its key difference is a long hydrocarbon tail, which not only makes the molecule very heavy (and thus odorless and extremely un-volatile—that is, it won't fly off into the air very easily), but also helps it bind to lipoprotein receptors on cell walls. Once bound to a cell, it triggers a reaction that causes the cell to undergo a reaction identical to the one caused by exposure to heat.***

***For a more detailed look at capsaicin and the other related vanilloids, take a look at this article from General Chemistry Online

Fish Filets in Special Chili Broth from Fuloon

That burning sensation you feel on your tongue? It's actually not a flavor sensed by your taste buds in the same manner as, say, sweetness or saltiness. It's an actual physical reaction that tricks your cells into telling your brain that they have been burned. Because that hydrocarbon tail has the ability to fit through cell membranes, the burning sensation can be quite long-lived, and because capsaicin has such an affinity for fat and dislike of water, drinking cold water to wash it away won't help.

Can We Get Rid Of It?

So if the capsaicin is all bound in the fatty phase of a chili or a spicy Sichuan dish, why can't we just remove that phase and get it over with?

There are a couple of reasons.

First off, it's nearly impossible to remove all fat from a dish. Sure, there's the big red oil slick that forms on top as you simmer a dish down, and while this may form a large part of the dish's fat content, there's still plenty of fat in the rest, either in the form of small droplets emulsified into the liquid, or within the meat and vegetables themselves. Our sensitivity to capsaicin is so great that even ten parts per million will trigger a reaction. Ain't no way you're going to get all of that capsaicin out of there.

Secondly, while it's true that large capsaicin molecules are not dissolvable in cold water, they are slightly soluble in hot water, and easily soluble in alcohol****. If I'm not mistaken, chili is usually served hot. And if you're like me, it's probably got some form of booze in it as well, whether it's a shot of bourbon or a pint of beer. So even after you've got the fat off the top, you're still going to have capsaicin dissolved directly into the liquid.

****If you've ever had a spicy alcoholic drink, you'd know this. It's also why beer or a shot of vodka will work better than plain water at cooling your mouth after a chili binge. Milk, with its lipophilic casein proteins, is better still.

Even if you refrigerate or freeze that chili, the capsaicin may break out of solution into microscopic solid crystals, but there's no way to get them out of a thick chili. They'll stay there until you reheat the stew and they can dissolve once again.

So if you take the fat off of your chili, you may be cutting down on heat a bit, but bear in mind that you'll also be cutting down on all the other wonderful fat-soluble flavors that have made their way into it, not to mention the flavor of the fat itself, which when stirred back into the chili, can be quite delicious.

Moral of the story: Let that fat be. If you want to cut down on chili heat, use fewer chilies, or cut out their white pith and seeds before adding them.

Got a question for The Food Lab?

Email your questions to AskTheFoodLab@seriouseats.com, and please include your Serious Eats user name in your email. All questions will be read, though unfortunately not all can be answered.

The Food Lab Lite: Pasta with Crab, Tomato, and Chilies

2013-03-26T13:15:53Z

[Photographs: J. Kenji Lopez-Alt]

Yeah, it's still snowing on and off in New York, but we're on the cusp of crabbing season, which probably explains why I've got crabs on the mind. It also helps that it's my wife's favorite seafood and she's about to embark on a six month west-coast sabbatical so I'm trying to squeeze in all the brownie points I can before she takes off for the sunnier climes.

As I discovered, finding quality crab in New York City is not an easy task in the ultra-early spring. I had to resort to taking to Twitter for recommendations and calling over a dozen seafood sellers around the city, only to find that the *only* one to be carrying fresh crab (I can't abide by the canned and pasteurized stuff) was the fish counter at Eataly. Now, despite the many great products that Eataly carries, I'd been burned by the fish counter there in the past with a rather expensive container of picked crab that turned out to be not-quite-so-fresh when I examined it at home.

Luckily, my Tweeted complaints were met with a prompt response and what appears to be an earnest attempt at rectifying the problems. I even had a chance to chat with the seafood manager to discuss ways in which product quality control could be improved. I've since returned to buy seafood from the counter three times and have indeed noted an improvement in quality and care shown to the display, so cheers to taking feedback and running with it, Eataly!

And what have I been doing with all this fresh crab? Well for one thing, making a butt-load* of crab cakes for an upcoming installment of The Food Lab. But on my way out of Eataly I couldn't help but notice the fantastic-looking fresh Spaghetti alla Chittara in the pasta department.

*did you know that a butt-load is an actual measure equivalent to 126 gallons or two hogsheads? True story.

My mind immediately drifted off to midtown and the fantastic Spaghetti with Crab, Sea Urchin, and Basil.

Their version is made by blending sea urchins into their pomodoro sauce, then tossing the whole thing with fresh-cooked pasta, crab meat, oven-dried tomatoes, and a sprinkle of bread crumbs.

Riffing on that setup, I decided to instead go with the vodka-cream sauce I'd been doing tests on last week the base for my dish. The brightness of the sauce and the sweetness of the crab really hit it off together. To the base I added a handful of sliced hot red chilies, reinforcing the heat in the sauce base.

With the sauce made, incorporating the crab is as easy as folding it in, taking care not to break it up too much. Crab has a way of ingratiating itself to its surroundings, its flavor blending in so that every strand of sauce-coated spaghetti gets its aroma and flavor whether chunks of it make it into your mouth or not.

Rather than Marea's basil, I went with a mix of parsley and chives, also tossing some in with the bread crumbs that I'd toasted in olive oil.

"Bread crumbs are a completely underrated pasta topping," said Ed. I agree. They add texture and absorb flavor without distracting and are the perfect counterpoint to an otherwise all-soft plate.

The resulting dish is so darn delicious I may even have to share it with my wife next time. Did I mention I finished it all before she got a chance? There go my brownie points.

Get The Recipe!

Pasta with Crab, Tomato, and Chilies »

Get the Recipe!

Ask The Food Lab: Does Vodka Sauce Really Need Vodka?

2013-03-21T18:15:00Z

"Does Vodka Sauce Really Need Vodka?"

I like penne alla vodka sauce. I'm curious whether or not the vodka adds anything to the mix. I'm dubious that A) the alcohol in the vodka actually brings any additional flavors out of tomatoes as people claim, and B) that one could even taste these nuances in tomato flavor after dumping a bunch of cream into the sauce. I'd be interested in a food lab investigation: does alcohol in fact draw out flavor from tomatoes?

—Sent by ctblair

It's not exactly clear where Penne alla Vodka comes from. Some say it's Italian, some say it's Italian-American, others claim it was invented by vodka manufacturers who tried to pass it off as Italian. All we do know for sure is that the dish—penne pasta tossed in a smooth, creamy sauce made with tomatoes, cream, and a splash of vodka—became popular in the U.S. some time in the late '70s and early '80s

Its history may be muddled, but its flavors are crystal clear. Simultaneously rich with cream but with a sharp, bright flavor from the vodka and crushed red pepper, it's the kind of sauce that's comforting in cold weather but makes you think of the warmer months ahead.

[Photograph: Joshua Bousel]

But the question posed is a good one. Does the vodka really add much to the sauce? Doesn't the alcohol all simmer off? Is it all just a ploy by the vodka manufacturers to get us to buy more of their hooch?

Harold McGee has a bit to say on the subject in his On Food and Cooking (get it NOW if you don't already own it). Check this out:

The alcohol molecule bears some resemblance to a sugar molecule, and indeed it has a slightly sweet taste. At high concentrations, those typical of distilled spirits and even some strong wines, alcohol is irritating, and produces a pungent, "hot" sensation in the mouth, as well as in the nose. Its chemical compatibility with other aroma compounds means that concentrated alcohol tends to bind aromas in foods and drinks and inhibit their release into the air.

Huh. I stopped reading when I got to that part and started scratching my head, because I know from past experience that adding alcohol to stews will increase their aroma. I tested it out in my Best Chili Ever recipe. What's he on about, inhibiting aromas?

But he quickly clears it all up:

But at very low concentrations, around 1% or less, alcohol actually enhances the release of fruity esters and other aroma molecules into the air.

A-ha! Now it makes sense: concentration is an important factor when it comes to its effectiveness as a flavor enhancer. This jibes with my past experience. Adding a bit of alcohol at the end of cooking is a good idea for stews and chilies, but too much and the booziness can become overpowering, leaving you smelling nothing but the alcohol instead of the better aromas its supposed to be carrying. Whiskey drinkers can tell you that diluting a dram from 40% ABV (Alcohol % by Volume) down to 30% or 20% ABV will also bring out aromatics that are otherwise hidden.

So does the same really happen to pasta with vodka sauce?

The Testing

To test out the effects of concentration and cooking, I made a huge batch of Sauced columnist Josh Bousel's Vodka Cream Sauce, leaving out the vodka. I then divided it into many batches.

For one set of batches I added varying degrees of vodka, diluting the alcohol content to various levels starting at 4% ABV of the total sauce down to 1%, tasting the sauce immediately after adding the vodka.

For the other set of batches, I did the same thing, but instead allowed the sauce to simmer for seven minutes after adding the vodka and before tasting.

Of the batches in which sauce was tasted immediately after adding the vodka, none were great. 4% was downright inedible, with a strong, alcoholic aroma and bitter flavor. I'm not exactly sure where the bitterness was coming from. Perhaps by masking the fruitier, sweeter aroma of the tomatoes, their bitterness was coming out more strongly?

In any case, only when I got down to 2% ABV did the sauce become bearable. I very slightly preferred the 1% sauce over the completely alcohol-free sauce. But just barely.

Cooking the sauce made a huge difference. After a seven minute simmer, even the 4% sauce became bearable, though the bright sweetness of the tomatoes didn't really start showing until I got back down to the 2% sauce (which, after simmering for a few minutes, must have settled down to closer to 1% in the end). The harsher flavors of the vodka dissipated, the bitterness was gone, and I was left with a nicely balanced sauce that packed a little bit more heat and bright aroma than the completely vodka-free sauce.

So to answer the question: yes! Vodka does alter the flavor of the sauce in a pleasing way. It adds a touch of heat and a bit of a sharp bite that help balance out the sweetness of the tomatoes and the cream. Is it absolutely necessary? No, but vodka sauce just wouldn't be, well, vodka sauce without it.

To get a vodka sauce with a 2% ABV before simmering, you'll need to add 5% of the volume of the sauce in 80-proof vodka. That breaks down to just under 1/4 cup per quart. (This means that our own recipe is slightly higher ABV than I prefer).

Leftover Thoughts

I also wondered about the question of leftovers. Does reheating the sauce end up eliminating too much vodka? I let a batch of my winning 2% ABV, seven-minute cooked sauce cool completely, then reheated it and divided it in two. One side I tasted as-is, while to the other side I added extra vodka and re-simmered it. The one with an extra 2 teaspoons of vodka per cup of sauce (about 2 1/2 tablespoons per quart) was the winner.

TL/DR version: For the tastiest vodka sauce, add 1/4 cup vodka per quart of sauce and let it simmer seven minutes. If you've got leftovers, just make sure you stir in an additional 2 teaspoons vodka per cup of sauce and let it simmer for a few minutes before serving again.

Got a Question for The Food Lab?

Email your questions to AskTheFoodLab@seriouseats.com, and please include your Serious Eats user name in your email. All questions will be read, though unfortunately not all can be answered.