Food
12:27 pm
Tue October 16, 2012

'Test Kitchen' Chefs Talk The Science Of Savory

Originally published on Tue October 16, 2012 2:22 pm

You might think that Bridget Lancaster and Jack Bishop — two of the culinary talents behind the public television shows America's Test Kitchen and Cook's Country — would have their cooking techniques pretty much figured out. Think again.

For the new Cook's illustrated book The Science of Good Cooking, Bishop and Lancaster tested principles they assumed were true — and as Bishop tells Fresh Air's Terry Gross, "Things that we thought were actually accurate turned out to be, perhaps, more complex."

Bishop and Lancaster also realized they had simplified certain techniques over the years, and that there was more to them than they initially thought.

One example: searing a steak. One of the common myths in many cooking books and taught in cooking school is that searing seals in juices.

"It is absolutely 100 percent false," Bishops tells Gross. He says the steak tastes better because the steak is browning and becoming more flavorful — but after running a number of tests, Bishop concluded that "whether you sear that steak at the beginning of the process or gently warm it in the oven and then quickly throw in a hot pan, the steak will weigh the same amount."

According to Lancaster, one of the most overlooked steps with respect to meat is letting it rest before carving into it.

"The difference between cutting into meat that's rested for 10, 20, 30 minutes and meat that has not rested at all, it's amazing," she says. The explanation? When cooked meat is just out of the oven, its fibers are very tight.

"If you cut into it right away, all of the moisture inside that meat will just flood out." Lancaster's suggestion: Let the roast sit — she suggests a minimum of 20 minutes — which will allow the meat fibers to relax so the juices pushed to the outside of the meat can be reabsorbed, and the meat will be juicier.

Jack Bishop is a cast member of America's Test Kitchen and Cook's Country and is the editorial director of America's Test Kitchen. Bridget Lancaster is the on-screen test cook for both shows.


Interview Highlights

On why you might want to add anchovies to your beef stew

Lancaster: "Glutamates ... [are] savory compounds; your taste receptors will pick that up and say, wow, that's nice and savory. But anchovies, in particular, they contain something else. It's another compound called a nucleotide — and a nucleotide plus a glutamate basically is a savory explosion. It really amps up the flavor of the glutamates 20, 30, even perhaps 40 times. So if you're tasting beef on its own, or soy sauce, or any of those glutamate-rich ingredients, your tongue will say, wow, that's very beefy. You add something with nucleotides in it, say anchovies, and you'll say this is the best beef stew ever. It tastes so much more meaty than meat."

On glutamate, MSG and 'Chinese restaurant syndrome'

Lancaster: "Glutamate is actually a naturally occurring compound. And MSG is derived from those naturally occurring compounds; it's just a manufactured product."

Bishop: "MSG did get something of a bad rap. They used to call it 'Chinese restaurant syndrome' where people were complaining of headaches after eating Chinese food, and they blamed — for a while, anecdotally in the press, the MSG.

"It turns out that it was probably bacteria growing in the rice, which had been cooked earlier in the day and [was] being kept warm in those restaurants ... and it really had nothing to do with the MSG. I do think MSG is a bit of a sledgehammer in terms of building flavor, and that taking a more natural approach using ingredients naturally rich in glutamates is a bit more subtle. And it's also certainly much more appealing."

On why you shouldn't be afraid of MSG

Bishop: "There's really no difference between what's in MSG and the glutamates that you find in mushrooms, in beef and all these other ingredients. It's not some scary, manufactured compound that doesn't really exist in nature; it's just a distilled version of something that exists in many foods that we normally eat."

On the myth of marinades

Bishop: "Your classic marinade ... is to use a bottle of Italian salad dressing. And ... the common thinking is that the acid — the vinegar in the salad dressing, or lemon juice, or red wine — is somehow tenderizing the meat. And you will read this in a lot of classic cooking manuals, that an acidic marinade will make meat more tender.

"It will, in fact, make the outer layer of the meat a bit mushy, but what it's really doing is pulling moisture out of the meat and making it drier. And there isn't really a great way to tenderize a cut that's going to be cooking very quickly, for instance on the grill, but you can make it juicier, and juiciness, when it gets to eating the steak, often is equated with tenderness once it's in our mouth.

"So we use a salt-based marinade; you can use salt itself, you can use a salty ingredient like soy sauce, and then mix that with the garlic, with all the seasonings you want to use. And what you're basically doing is, the salt penetrates very quickly into the meat and changes the structure of the muscle proteins, so that when the muscle proteins are cooked, they will hold on to more of their juices."


Recipe: Best Beef Stew

Serves 6 to 8

Use a good-quality medium-bodied wine, such as a Cotes du Rhone or pinot noir, for this stew. Try to find beef that is well marbled with white veins of fat. Meat that is too lean will come out slightly dry. Look for salt pork that is roughly 75 percent lean.

2 garlic cloves, minced

4 anchovy fillets, rinsed and minced

1 tablespoon tomato paste

1 (4-pound) boneless beef chuck-eye roast, pulled apart at seams, trimmed, and cut into 1 1/2‑inch pieces

2 tablespoons vegetable oil

1 large onion, halved and sliced 1/8 inch thick

4 carrots, peeled and cut into 1‑inch pieces

1/4 cup all-purpose flour

2 cups red wine

2 cups low-sodium chicken broth

4 ounces salt pork, rinsed

2 bay leaves

4 sprigs fresh thyme

1 pound Yukon Gold potatoes, cut into 1‑inch pieces

1 1/2 cups frozen pearl onions, thawed

2 teaspoons unflavored gelatin

1/2 cup water

1 cup frozen peas, thawed

Salt and pepper

1. Adjust oven rack to lower-middle position and heat oven to 300 degrees. Combine garlic and anchovies in small bowl; press with back of fork to form paste. Stir in tomato paste and set aside.

2. Pat meat dry with paper towels. (Do not season.) Heat 1 tablespoon vegetable oil in Dutch oven over high heat until just starting to smoke. Add half of beef and cook until well browned on all sides, about 8 minutes. Transfer beef to large plate. Repeat with remaining beef and remaining 1 tablespoon vegetable oil, leaving second batch of meat in pot after browning.

3. Reduce heat to medium and return first batch of beef to pot. Add onion and carrots to Dutch oven and stir to combine with beef. Cook, scraping bottom of pot to loosen any browned bits, until onion is softened, 1 to 2 minutes. Add garlic mixture and cook, stirring constantly, until fragrant, about 30 seconds. Add flour and cook, stirring constantly, until no dry flour remains, about 30 seconds.

4. Slowly add wine, scraping bottom of pot to loosen any browned bits. Increase heat to high and allow wine to simmer until thickened and slightly reduced, about 2 minutes. Stir in broth, salt pork, bay leaves, and thyme. Bring to simmer, cover, transfer to oven, and cook for 1 1/2 hours.

5. Remove pot from oven; remove and discard bay leaves and salt pork. Stir in potatoes, cover, return to oven, and cook until potatoes are almost tender, about 45 minutes.

6. Using large spoon, skim any excess fat from surface of stew. Stir in pearl onions; cook over medium heat until potatoes and onions are cooked through and meat offers little resistance when poked with fork (meat should not be falling apart), about 15 minutes. Meanwhile, sprinkle gelatin over water in small bowl and let sit until gelatin softens, about 5 minutes.

7. Increase heat to high, stir in softened gelatin mixture and peas; simmer until gelatin is fully dissolved and stew is thickened, about 3 minutes. Season with salt and pepper to taste; serve.

Why This Recipe Works
This recipe uses evenly cut chunks of chuck-eye roast — one of the cheapest, beefiest cuts in the supermarket — which we brown and gently simmer in a rich broth. We flavor this broth with glutamate-rich ingredients like salt pork and tomato paste, and thicken it with gelatin. Beef and anchovies are also a good source of nucleotides that work synergistically with glutamates.

Cut Your Own Meat
Using packaged "stew meat" from the supermarket is a nonstarter here; the jumble of scraggly bits and large chunks from all over the cow (some of which are too lean to be stewed) is impossible to cook evenly. We prefer chuck-eye roast, which can turn meltingly tender when properly cooked. To ensure consistent texture and flavor, trim and cut the meat yourself. First, pull apart the roast at its major seams (marked by lines of fat and silverskin). Then, with a sharp chef's knife or boning knife, trim off the thick layers of fat and silverskin. Slice the meat into even, stew-ready chunks.

Build Flavor
We build flavor a number of ways in this stew — from browning to using glutamate- and ­nucleotide-rich ingredients in the sauce. We also sauté the aromatics. Caramelizing the onion and carrots (rather than just adding them raw to the broth, as many other recipes suggest) helps to start the stew off with as much flavor as possible. We like to leave the meat in the pot while the vegetables sauté, as the residual heat helps the vegetables to cook faster and more evenly.

Fish for Meatier Flavor
To boost meaty ­flavor in food, we often add ingredients high in glutamate. This common amino acid is the building block for MSG and occurs naturally in foods from mushrooms to cheese, tomatoes, and fish. Thus it wasn't exactly a surprise that the addition of two such glutamate-rich ingredients — tomato paste and salt pork — to our beef stew intensified its savory taste. But when we added a third ingredient, anchovies, the beefy flavor seemed to increase exponentially. This is because anchovies also contain compounds called nucleotides, which scientists have found to have a synergistic effect on glutamate, heightening its meaty taste 20- to 30-fold.

Stagger the Vegetables
We stagger the addition of vegetables to the stew in order to prevent overcooking. Medium-starch Yukon Gold potatoes, which aren't as starchy as russets and therefore won't break down too easily and turn the stew grainy, are added 1 1/2 hours into the stewing time. Pearl onions are added 45 minutes later, and a handful of frozen peas are added at the very end.

From The Science of Good Cooking (Cook's Illustrated Cookbooks) by Cook's Illustrated Magazine. Copyright 2012 by the Editors at America's Test Kitchen. Excerpted by permission of Cook's Illustrated.


Recipe: Hot Cocoa

Serves 4 in small mugs

Why This Recipe Works
Our ideal hot cocoa recipe would give us serious chocolate flavor and a rich, satisfying consistency. We found that 1 1/2 tablespoons of cocoa powder sweetened with 1 tablespoon of sugar added enough chocolate flavor to our hot cocoa recipe without being overpowering. Many recipes recommend mixing cocoa powder and sugar with a little water before adding the milk, and we found this to be worthwhile. Water has the effect of releasing the cocoa powder's fruit, chocolate, and coffee flavor nuances. We also discovered that heating the mixture of cocoa powder, sugar, and water for two minutes before adding milk further deepens the flavor.

If you want to increase or decrease this recipe for hot cocoa, the key ratio to remember is one and one-half tablespoons of cocoa and one heaping tablespoon of sugar per cup of liquid. If you have whole milk on hand rather than low-fat, go ahead and use it, omitting the half-and-half.

Ingredients

6 tablespoons Dutch-processed cocoa powder, measured by dip-and-sweep

4 tablespoons granulated sugar

Pinch table salt

1cup water

3 cups low-fat milk (1 or 2 percent)

1 teaspoon vanilla extract

1/4 cup half-and-half

Instructions

1. In heavy 2-quart saucepan, whisk together cocoa, sugar, salt, and water over low heat until smooth. Simmer, whisking continuously, for 2 minutes, making sure whisk gets into the edges of pan.

2. Add milk, increase heat to medium-low, and cook, stirring occasionally with whisk, until steam rises from surface and tiny bubbles form around edge, 12 to 15 minutes. Do not boil.

3. Add vanilla and half-and-half. For foamy cocoa, beat hot cocoa with hand mixer or transfer to blender and blend until foamy. Divide between four mugs, top with whipped cream or marshmallows if desired, and serve immediately.

Excerpted by permission of Cook's Illustrated.

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.

Transcript

TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. With us for a return visit are two cooks who are constantly challenging common wisdom in an attempt to come up with quicker, easier, tastier ways of preparing food. Jack Bishop and Bridget Lancaster work with the public TV shows "America's Test Kitchen" and "Cook's Country."

Jack Bishop is a cast member of both shows and editorial director of "America's Test Kitchen." Bridget Lancaster is the onscreen test cook for both shows. They've both contributed recipes to the new Cook's Illustrated book "The Science of Good Cooking," which features 400 recipes, along with explanations of the fundamental principles behind the recipes.

Bridget Lancaster, Jack Bishop, welcome back to FRESH AIR. Bridget, you contributed a lot of recipes to this new book. Jack, the idea for the book was yours, and it sounds like you oversaw a lot of it. Why did you want to do a book on the science of cooking?

JACK BISHOP: Cook's Illustrated magazine, for the last 20 years, has really been writing about food and the science of cooking. And I thought it was time to really put together a manual of best practices and to really explain how food works from a scientific perspective and to really take all of that accumulated knowledge that we had gained over 20 years of recipe testing and put it into a single book for the person who really wants to learn to cook or become a better cook through the lens of science, analysis, testing and improving.

GROSS: So did the fact that Cook's Illustrated was working on a science of cooking book change the emphasis in the test kitchen?

BISHOP: Yeah. We went back to a lot of things that we thought were true and decided we were going to re-examine pretty much all of them. And we conducted a lot more experiments, and it was really interesting. Things that we thought were actually accurate turned out to be perhaps more complex, was usually the issue - not necessarily that things were wrong, but that we had simplified them over the years and that there was more to it than we initially thought.

GROSS: Give me an example.

BISHOP: A good example would be the whole issue of one of the common myths that you will read in any book or if you go to cooking school is that searing seals in juices, so that when you're searing a steak, what you're doing supposedly is sealing in the juices. It's absolutely, 100-percent false. You are not sealing in any juices.

You are making the steak taste better because you are causing browning, which is initiating a process called the Maillard reaction, making the steak browner and more flavorful. But we ran a number of tests and concluded that there's absolutely no truth to that. In fact, whether you sear that steak at the beginning of the process or whether you gently warm it in the oven and then quickly throw it in a hot pan, the steak will weigh the same amount before and after cooking, whether you sear at the very beginning or you sear at the very end.

GROSS: Is that how you measure whether it has more moisture in it or not, whether it's juicier, by weighing it?

BISHOP: That's usually the way we would measure something like that. I mean, we will do sensory tests, where we'll have people in the kitchen taste a sample. But what we really wanted to do for this book - and I think something that we did sort of out of the norm - is we really tried to measure things, and tons of weighing, analysis, working with the food lab and really trying to quantify what we were seeing.

We repeated the tests. So if we did any test, we did it usually at least five times, looking to make sure that, you know, from a science perspective, that we were on solid ground.

GROSS: Bridget, you contributed several of the recipes in this new book, "The Science of Good Cooking." So is the beef stew recipe one of yours?

BRIDGET LANCASTER: The beef stew recipe - actually, the beef stew recipe that runs in that is not directly mine, but I'd say I'm the grandmother of that recipe, perhaps.

(LAUGHTER)

GROSS: OK.

LANCASTER: There's a lot of science that went behind choosing every single ingredient, and a lot of that was done in the early days. But this is a great example of a recipe that we thought we knew everything about beef stew, and then we went back and we questioned certain aspects of it.

How can you get a beef stew that tastes amazingly beefy with meat that's super-succulent and juicy, melt-in-your-mouth, but also working with supermarket ingredients like canned beef broth? How could that ever produce such a rich, flavorful and unctuous beef stew?

GROSS: OK. So let's talk about beef stew, because it's a great winter dish.

LANCASTER: Oh, yes.

GROSS: And it's - the cold weather's coming.

LANCASTER: It's on its way.

GROSS: Or it's here, depending on where you are. So, first of all, with the beef stew, you suggest do not buy stew meat. Why not, and what should you buy?

LANCASTER: Well, meat that's already pre-cut-up into pieces and labeled as stew meat, we're not actually sure exactly where that came from in the cow. There's a couple problems with it. One is it's hard to identify if it's from one of the better cuts - say, the chuck or the shoulder area of the cow has tons of intramuscular fat and collagen running through it.

So when that beef is cooked nice and slow, the collagen melts, and it turns into gelatin. The gelatin's what gives that stew meat that really silky feel, and that's what we want. Sometimes stew meat comes from the sirloin, which is a leaner cut, or from the round, which is not the best thing for stewing. So that's one of the problems, is getting, you know, the right cut.

The other problem is the size of stew meat. Often, you get stew meat, and it's tiny, tiny pieces of meat. Well, during that long, slow cooking, the meat really, really shrinks. So if you want meat that's not going to fall apart in the stew, you want to start with bigger, chunkier pieces of beef. So definitely good to get a chuck eye roast or a chuck roast from the shoulder, a blade at the very least, but a chuck eye is great, and cut it up yourself. It takes 10 to 15 minutes, really, to do it.

GROSS: And what else are you putting in?

LANCASTER: Oh, a lot of good stuff. So we want a beef stew that tastes really rich, very, very beefy. So beef will, oddly enough, only get you part of the way there. So one of the things that we find is that adding ingredients that contain a lot of glutamates - glutamates are a savory compound. Basically, your tongue says, wow. This is beefier. This is savory, if it tastes of glutamate - so things like tomato paste or salt pork, mushrooms. But in this case, one of the odd ingredients that we used was anchovies.

GROSS: And this gets to one of the principles that I really love from your book, which is combining the glutamates with things like anchovies or sardines. So explain what's going on scientifically and what happens when these two groups of tastes combine.

LANCASTER: Right. So the glutamates, which I mentioned before, it's a savory compound. Your taste receptors will pick that up and say, wow. This is nice and savory. But anchovies, in particular, they contain something else. It's another compound called a nucleotide. And a nucleotide plus a glutamate basically is a savory explosion. It really amps up the flavor of the glutamates 20, 30 even perhaps 40 times.

So if you're tasting beef on its own or soy sauce or anything, any of those glutamate-rich ingredients, you tongue will say, wow, this is very beefy. You add something with nucleotides in it, say anchovies, and you'll say this is the best beef stew ever. It tastes so much more meaty than meat, believe it or not.

GROSS: So tell us the foods in both categories, the nucleotides and the glutamates.

LANCASTER: Well, glutamates - and the anchovies also contain glutamates, I should say. So salt pork, tomato paste, the anchovies I mentioned before, soy sauce is used a lot, Worcestershire sauce, meat in general. Those are probably the most common ones. So things like the anchovies are really rich in the nucleotides. Jack, I don't know offhand...

BISHOP: Dried mushrooms are another good source of nucleotides. And, you know, as Bridget was saying, all those things from the sea: shrimp, believe it or not sea urchin - not sure we're going to throw those into beef stew anytime soon. But, you know, that combination, as Bridget said, really just makes tremendously complex, meaty flavor, and we use that in a lot of our cooking, even in dishes where you wouldn't think - you know, where meat is not necessarily star, thinking about like in a tomato sauce, and ramping up the savory sort of - generally savory notes in something, using both glutamates and nucleotides can be a great way to make something more flavorful.

GROSS: So getting back to our beef stew recipe, what do you do for a good broth? You've got the meat. You've got the glutamates with a little bit of anchovies in it as the big surprise to release the explosion of savory taste.

LANCASTER: So, well, one thing I should point out about the anchovies, for anybody out there listening and saying anchovies: You don't taste anchovies. It does not taste like a fish stew. So I should say that. It's kind of like a Caesar salad, where you have this really deep-flavored dressing.

But getting back to the broth, you know, we try to use ready-made ingredients or convenient ingredients. So we're not going to ask people to make a homemade stock for this. And if you were to have the best beef stew in the world at a restaurant, it probably is using veal stock. So they roast the bones, sometimes with tomato paste and sometimes with vegetables, and then they simmer it very slowly. And all that collagen is released from the bones and the meat, and it converts to gelatin, the same thing as I explained before with the meat.

Well, if you're using canned broth, you're not going to get all that gelatin that gives almost the silky feel to beef stew that using a veal stock would. So we were looking for gelatin, so we thought: Why not get a box of Knox, you know, just the old gelatin that you used for, you know, your jiggly desserts back in the 1950s?

And a little bit of powdered gelatin right over the sauce, and we let it bloom and then finish the broth with it, gives it just a really nice body, kind of clings to the spoon a little bit - also clings to your ribs, too.

GROSS: OK, so getting back to the glutamates, they're related to MSG, monosodium glutamate, which has been literally X'ed off of most menus now. Like, Chinese restaurants used to be famous for having MSG in their dishes. Now so many of those restaurants have the, you know, X, no MSG. So what is MSG? You've just sung the praises of glutamates. What's the difference between glutamates and monosodium glutamate?

LANCASTER: Hmm. That's an excellent question. Well, I know that glutamate is actually a natural-occurring compound, and so is - MSG is derived from those naturally occurring compounds. It's just it's a manufactured product. But there really is not any concrete evidence that MSG is going to give you that reaction of a big headache.

And, in fact, you know, you don't need - the end of the story is you don't need to grab a package of MSG off of the shelf. You're better off using, as Jack said, dried mushrooms, anchovies, tomato paste, tomatoes, soy sauce, things like that, to basically really add that savory component.

So, MSG I think of as one of those things that we didn't understand back then. It certainly does add that - you know, we did tests in the Test Kitchen where we added MSG to food, tasted it alongside food that did not have MSG added to it, and you could definitely taste a deeper flavor. But I think it's one of these foods that people have been accustomed to being afraid of. But in any case, you don't need it. Just get some mushrooms instead.

GROSS: And make sure you saute the mushrooms first or something, right?

LANCASTER: Sure.

GROSS: Yeah, bring out the flavor.

LANCASTER: Definitely.

GROSS: OK.

BISHOP: And Terry, you know, the MSG did get somewhat of a bad rap. You know, they used to call it Chinese restaurant syndrome, where people were complaining of headaches after eating Chinese food, and they blamed - for a while, anecdotally in the press - the MSG.

It turns out that it was probably bacteria growing in the rice which had been cooked earlier in the day and being kept warm in those restaurants which was causing the headaches that people were complaining about after eating Chinese food, and it really had nothing to do with the MSG.

I do think MSG is a bit of a sledgehammer in terms of building flavor, and that taking a more natural approach, using ingredients naturally rich in glutamates, is a bit more subtler, and it's also certainly much more appealing.

GROSS: But you're also saying you don't have to be terrified of MSG.

BISHOP: No. I mean, there's really - other than in its pure form, there's no difference between what's in MSG and the glutamates that you find in mushrooms and beef and all these other ingredients. It's not some scary, manufactured compound that doesn't really exist in nature. It's just a distilled version of something that exists in many foods that we normally eat.

GROSS: Hmm. OK. If you're just joining us, we're talking about cooking and the science of cooking. In fact, "The Science of Cooking" is the name of the new recipe book put out by Cook's Illustrated, and both of my guests have worked on that. Bridget Lancaster is the onscreen test cook for the public TV shows "America's Test Kitchen" and "Cook's Country." Jack Bishop is a cast member of both of those shows and is the editorial director of "America's Test Kitchen." Let's take a short break, then we'll talk some more. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: Well, if you're just joining us, my guests are Jack Bishop and Bridget Lancaster, and there's a new Cook's Illustrated book called "The Science of Cooking" that was Jack's idea, and Bridget contributed some of the recipes. And Bridget is the onscreen test cook for the public television shows "America's Test Kitchen" and "Cook's Country." Jack is a cast member of both those shows and is the editorial director of "America's Test Kitchen."

As we've discussed in previous shows, Bridget, you love meat dishes, and Jack, you're very into vegetarian dishes. So let's do a vegetarian side dish here, and this is for creamy Parmesan polenta. Oh, it sounds good. And what you've tried to do here is create a recipe where you don't have to constantly stir the polenta, and you can cook it in less time than most polenta takes to cook. So what's the trick?

BISHOP: Well, the classic recipe for making polenta is, you know, you think there's an Italian grandmother - including my Italian grandmother - sitting in a kitchen, stirring a pot of cornmeal, water and salt. That's really all polenta is. And the classic recipe literally calls for you to stir constantly for one hour.

It's a great workout for your upper body. Those muscles really can get a lot stronger. But most people want to avoid recipes that call for stirring for one hour. So the reason why you need to cook the polenta that long is, you know, you add the cornmeal, and you think: Well, isn't it done? And the cornmeal's not fully hydrated.

And what you're really doing by continuing to cook and stir is allowing the water to fully be absorbed by the cornmeal. And so we had two tricks to cut down on the cooking time and to reduce the stirring. The first was we add just a pinch of baking soda to the pot. And what the baking soda is doing is creating an alkaline cooking environment, and that alkaline environment is breaking down the pectin that holds the different cells within the cornmeal together.

And once those cells come apart, once the pectin dissolves, the water can easily penetrate into those cells and hydrate the cells, and therefore the cornmeal will soften and become properly cooked. So that basically will cut the cooking time from 60 minutes to 30 minutes, but it doesn't solve the stirring problem.

We solve the stirring problem by simply using the absolute lowest heat and throwing the lid on a heavy pot. So if you're using like a heavy Dutch oven and you put the lid on it and then turn the heat all the way down to very low, it's not going to scorch. And so you can simply stir it twice during the 30-minute cooking time, and you don't need to be standing over the pot, working out your biceps.

GROSS: Now, do you get it to boiling before you turn down the heat, or do you just keep it on the low heat?

BISHOP: You bring it up to a boil. What you're doing is you're bringing the water and the salt to a boil. You're slowly adding the cornmeal, whisking, trying to prevent lumps. It'll pretty much come back to a boil instantaneously once you've added the cornmeal. And then you turn the heat all the way down, as low as it can possibly go.

Basically, you want it to be at a lazy, lazy simmer, the occasional bubble. If your stove is one that kind of runs hot, you might even use a flame tamer. But the most important thing is to be using a heavy pot with a heavy bottom and then putting the lid on, which will trap that moisture and prevent scorching.

GROSS: And why is the heavy pot important?

BISHOP: That keeps the heat from the burner from really causing the bottom of the polenta to scorch, and that basically the heavier the pot, the thicker the bottom, the more even the cooking is going to be, no matter what you're cooking, whether you're cooking a stew or polenta.

And so, you know, those Dutch ovens that are cast iron with the enamel coating that weigh eight pounds, nine pounds, there's a reason why they're that heavy. For this kind of cooking that's low and slow, they're going to make sure that the even heat is distributed throughout the entire pot.

GROSS: So where does the parmesan come in?

BISHOP: You finish with parmesan and butter. And so after the 30 minutes, take the lid off, you need to add a little bit of butter. You can use as much or as little as you want. And then the Parmesan is there for, obviously, flavor. And, you know, I will serve creamy Parmesan polenta as a side dish, on its own. It's also a great anchor under any sort of stew, whether it's a vegetarian stew with beans and vegetables, or whether it's a beef stew. And, of course, the classic Italian pairing of polenta and osso bucco is absolutely fabulous.

But I think it's a sort of nicer partner with any sort of stew than the usual noodles or potatoes. I think it has a little bit more flavor, and it's a little unexpected.

GROSS: Jack Bishop and Bridget Lancaster will be back in the second half of the show. They both work on the public TV programs "America's Test Kitchen" and "Cook's Country" and have contributed to the new book "Cook's Illustrated: The Science of Good Cooking." You'll find the recipes we've talked about on our website: freshair.npr.org. I'm Terry Gross, and this is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. I'm Terry Gross. We're talking about ways of making recipes easier and tastier with Bridget Lancaster and Jack Bishop of "America's Test Kitchen," which is the home of the magazines "Cook's Illustrated" and "Cook's Country" and the public TV shows "America's Test Kitchen" and "Cook's Country."

Bridget Lancaster is the on-screen test cook for both shows. Jack Bishop is a cast member on both shows and editorial director of "America's Test Kitchen." They've both contributed to the new book "The Science of Good Cooking."

I want to ask you both about the principles - some of the scientific principles - that are in the new book "The Science of Good Cooking." I didn't know this, but you say putting sugar on fish will brown it. I've kind of used that principle by just, you know, putting on - this might appall you - putting on teriyaki sauce at the last minute and that really helps brown it, I found, but, you know, because I'm putting it on while it's still in the pan.

LANCASTER: Sure.

GROSS: OK. So, but you suggest just sprinkling on some sugar.

LANCASTER: Well, it makes little bit of sense if you think about what you're cooking, you're cooking a piece of fish. So to brown it, say, in a skillet, you don't want that fish to stay in a long, long time because fish cooks very quickly. So in order to speed up the browning - which again, browning creates a lot of flavor - not only do we salt and pepper the fish but just add I mean a little sprinkling of sugar at that point because the sugar will quickly caramelize. It doesn't taste sweet at all but it translates to a deeper flavor very quickly. And, you know, this trick works great with chicken breast or we use it on very little lean pork chops, things like that, cutlets, things that you want to brown quickly but they're in danger of overcooking if they were to spend all day in the pan, getting a nice dark color.

GROSS: OK. And in your book you say marinades don't tenderize meats. But if you're going to do a marinade, a salty marinade works best. What are the scientific principles behind marinades and why some marinades work and some don't?

BISHOP: I'll take this one, Terry.

GROSS: OK.

BISHOP: Your classic marinade - pretty much everyone has done this at some point in their life - is to use a bottle of Italian salad dressing. And you're thinking - at least the common thinking is that the acid - the vinegar in the salad dressing, or lemon juice, or red wine - is somehow tenderizing the meat. And you will read this in a lot of classic cooking manuals, that an acidic marinade will make meat more tender.

It will, in fact, make the outer layer of the meat a bit mushy, but what it's really doing is pulling moisture out of the meat and making it drier. And there isn't really a great way to tenderize a cut that's going to be cooking very quickly, for instance on the grill, but you can make it juicier, and juiciness, when it gets to eating the steak, often is equated with tenderness once it's in our mouth.

And so, we use a salt-based marinade; you can use salt itself, you can use a salty ingredient like soy sauce, and then mix that with the garlic, with all the other seasonings that you want to use. And what you're basically doing is, the salt penetrates very quickly into the meat, it changes the structure of the muscle proteins, so that when the muscle proteins are cooked, they will hold on to more of their juices.

You know, the great challenge in any sort of protein cookery is that the more you cook it, the more flavor that you're developing on the exterior, but the more moisture is evaporating. And so what a salty marinade will do will slow down the process of the moisture evaporating and the steak or the chicken cutlet drying out. It'll also provide some nice seasoning so that it gives you time to get some nice browning and to fully cook that piece of meat.

GROSS: And if you're going with a salty marinade, how long would you do that for?

BISHOP: Thirty minutes. You know, of course, it will depend upon the strength. But if you're making a marinade, let's say, with, you know, a third of a cup or a quarter of a cup of soy sauce you always want to salt - throw oil in with the marinade because the oil will distribute a lot of the fat soluble compounds that are in spices and in herbs evenly throughout the meat, and then you can add, you know, your dried spices, your herbs, and what we usually do is we don't put the acidic ingredient in the marinade. It's something that we might use at serving time, for instance. So if you're marinating chicken cutlets and you like - or chicken breasts - and you like the idea of lemon, serve it with lemon wedges and use a squirt of lemon at that point. But throwing the lemon into the marinade - at least the lemon juice - really is just making the meat mushy and dry.

GROSS: OK. So another question that you write about in "The Science of Good Cooking" is, you know, the relative merits of cooking with water and cooking with air. And, you know, you say water is a more efficient conductor of heat than air and is capable of cooking food very quickly, an oven cooks more slowly. So how do you weigh the relative merits between, you know, cooking with water and cooking in the oven and combining the two?

(LAUGHTER)

GROSS: You know, having moisture in, you know, kind of like a stew, moisture in the oven?

LANCASTER: Well I...

GROSS: Moisture in the pot that your cooking in the oven?

LANCASTER: Sure. I think the moist cooking environment is what you were talking about - stewing, brazing is another one where it's more of a shallow - think of it as a shallow stew with slightly larger pieces of meat or even pot roasting. So the pot would contain at least halfway up the sides liquid and you're pot roasting a nice big piece of beef or pork. I think you choose these methods, you choose a slow, moist cooking method - stewing, brazing or pot roasting, for a couple of reasons. One, the moisture really does do a great job of breaking down the intramuscular fat. It also, the water, or the liquid in the pan, is not going to go above 210, 211 degrees. At that point it would start to boil and turn to steam. So you're already using a much lower heat than you can control with dry roasting. And then the other reason is you like gravy. I mean I could put gravy on just about anything. So the moist - it's a, you know, the moisture gives tenderness to the meat but then or whatever food you're doing, and then the food gives an amazing flavor, creating a sauce at the same time.

So I think with really, really tough cuts my preference is - my personal preference is for moist heat cooking. There are exceptions to that; we did a slow roasted beef. We've done actually slow roasted pork as well, but the slow roasted beef was kind of the first time we took an insanely tough cut around a beef round and cooked it at an incredibly low temperature to basically, because what we found was that this really, really low temperature, there are enzymes and enzymes inside beef that tenderizer it. I think it's below; the meat has to be below 122 degrees. I'm pretty sure that's the cutoff point. But below 122 degrees, the enzymes that are turned on by this low heat method, they act almost like little buzz saws in there and they cut down the tough tissue in a really, really tough cut of meat and several hours later you end up with a roast that, I mean before this experiment I probably would've not roasted a round from a beef. It's not my ideal cut, but after this it was amazing that the beef was so much more flavorful and it was so incredibly tender, it didn't need a knife to cut it. So either way you're going, the brazing, the stewing or slow oven roasting, they're all different methods of slowly breaking down meat, tough cuts, to make it much more tender.

GROSS: OK. So speaking of slow cooking, what do you both think of crock pots?

LANCASTER: I love them.

(LAUGHTER)

BISHOP: I'm a convert. As somebody who never used a crock pot until about three years ago, I'm convinced.

GROSS: What are your favorite dishes to make in the crock pot?

BISHOP: My favorite things are anything that benefits from, you know, slow low cooking. You know, if it's I see recipes that people try to roast a chicken in the crock pot, that seems a little crazy to me. It's not really the best use of a crock pot. And so I make chili in a crock pot. The advantages, that you can do all the prep work and, you know, go out of the house and go do things for eight hours and come back and the chili is ready to serve. Stews are great in a crock pot. Beef stew is just, you know wonderful in a crock pot. You do need to adjust recipes. A couple of things I found is that you need to add more flavorful ingredients and there's almost no evaporation. And so sometimes you need to cut back the amount of liquid that you would normally use otherwise, the end product can be a little on the sort of soupy side. But I love them.

LANCASTER: I'm the same way and I'm a year-round slow cooker fan. And in the winter during the holidays I think I'm one of the last five people on earth to only own one of oven, so the slow cooker becomes my second oven. If I have a lot of people over, I will say for Thanksgiving, I'll have roast turkey but I'm not going to roast two turkeys. So I'll have a roast turkey and I'll have a stew on the side. And then in the summer, I don't want to turn on my oven because it's an old oven. It heats up the whole house. So again, it's a great time, a great piece of equipment to use. And the other thing that I like to make in it is - and I know it's not true barbecue - but I love to make things like pulled pork, pulled chicken, all these things they really translate to - translate well to the slow cooker.

GROSS: Bridget, I think you've been hanging around with cooks too long, if you're the only person you know who doesn't have two ovens. I don't think I know anybody who has two ovens.

(LAUGHTER)

LANCASTER: I think you're probably right.

GROSS: Yeah. Think about that.

(LAUGHTER)

GROSS: My guests our Bridget Lancaster and Jack Bishop of "America's Test Kitchen." They've contributed to the new book Cook's illustrated "The Science of Good Cooking."

We'll talk more after a break. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: If you're just joining us, we're talking about cooking, winter foods and the science of cooking. "The Science of Good Cooking" is the name of the new book published by Cook's illustrated. I have two guests. Jack Bishop came up with the idea for the book and basically oversaw it and Bridget Lancaster contributed some of the recipes. Bridget is the on-screen test cook for the public TV shows "America's Test Kitchen" and "Cook's Country." Jack is a cast member of both of those shows and is the editorial director for "America's Test Kitchen."

So, another principle in your book is that rubbing chicken skin - chicken that you're going to roast - with cornstarch can crisp the skin. Why is that?

LANCASTER: This is pretty amazing, but when you think about what cornstarch does, cornstarch is a starch obviously, and it wakes up moisture. So when you're thinking of chicken skin - and not the meat, obviously, you want to rub it with usually we do a mixture of both cornstarch and salt together, and it is going to start pulling out some of the moisture from the skin. So when you go to roast it, the moisture is at the surface, it can quickly evaporate and you end up with a much crisper skin. It's great for turkey. It's great for chicken. We've even used it a couple of times rubbing it right on the surface of things like pork chops, steaks before we put them on the grill to get a really substantial crust, so it's a good trick.

GROSS: You like to rest meat in between, you know, cooking it and carving it and that's, in part, to keep the juices in.

LANCASTER: Definitely. And that's, I think that's one of the most overlooked steps of any recipe. The difference between resting meat, cutting into meat that's rested for 10 minutes, 20 minutes, 30 minutes, and meat that has not rested at all and you cut right into it, it's amazing. So basically, you take a piece of meat out of the oven and the fibers are very tight, so they're bound together. So if you were to cut into that meat right away, all the moisture that's inside that meat will just flood out onto your cutting board. Well, that means dried meat, really moist cutting board. So if you're enjoying cutting board for dinner you're all set, but the meat will be dry. But by letting that roast sit there for at least - depending on the size of the roast - at least 10, 15, 20 minutes, 20 minutes to me is the minimum, the meat fibers which were really, really tight are now starting to relax, the juices that were pushed to the outside of the meat are now able to reabsorb back into it. And then you can cut into the meat, the meat will be juicy, you'll have very little loss of juice to your cutting board.

It's worth it, I think, to - especially, you know, a really expensive roast or just about anything, to let it sit there for at least 20 minutes.

GROSS: So with winter on the way, I'd like you to each recommend your favorite cold weather drink. Not Scotch.

LANCASTER: Darn it.

(LAUGHTER)

GROSS: Like something that you actually make.

LANCASTER: Cold weather drink. For me it's probably mulled cider. And you can choose to put a little Calvados into that if you care for it. A nice cider from, you know, the local orchard if you can, and you can bloom the spices. Your cinnamon stick, break it up, your nutmeg, whatever you like in that.

I think mulled cider for me is - and I don't really have a recipe. I kind of throw things in hickledy-pickledy until it tastes good. And a little bourbon at the end is perfect.

GROSS: And Jack?

BISHOP: For me it's hot cocoa. I have not had hot cocoa in probably six months and I'm looking forward to another couple weeks when it gets cold enough that I'm going to want to have a cup of cocoa every evening. And so hot cocoa, as the name implies, I think should be made with cocoa powder rather than chocolate.

Believe it or not, cocoa powder has two or three times as much flavor as an equivalent amount of chocolate because chocolate also has fat in it and cocoa powder is pretty much pure cocoa solids, meaning pure flavor and very little of the cocoa butter, which is the fat. And so I will take a small amount of cocoa powder and mix it with a small amount of sugar and then a small amount of milk, and dissolving them, sort of whisking them together to make a sort of thick paste and then adding the remainder of the milk in order to thin that out. And I think it's really important - I usually use skim milk in my cereal, but I think if you're going to make hot cocoa, you kind of want to use whole milk. And then a little teeny bit of salt. In a lot of beverages that have sugar in them, adding a pinch of salt will kind of balance out the sweetness and heighten the flavors the way it does in savory foods.

GROSS: Well, I have to say that tastes and smells very good the way I'm imagining it. And speaking of cocoa, I mean you suggest in recipes, for instance like chocolate cupcakes, that you use cocoa instead of chocolate, or at least make some substitution there.

BISHOP: Yeah. This principle is really interesting, that people think, oh, bar chocolate has the best flavor because they're thinking about their experience of, you know, eating it out of the package. And you're not going to eat unsweetened cocoa powder. But chocolate actually is 50 percent cocoa butter, which is the fat that's in bar chocolate that gives it that luscious texture, and it's 50 percent cocoa solids.

Cocoa solids are what makes chocolate taste like chocolate. And so in order to make cocoa powder, they take pure chocolate that's half fat and half cocoa solids and remove almost all of the fat. And so a spoonful - a spoonful - it's just got an intense amount of chocolate flavor. And so when we're making cupcakes, when we are making cakes, even when we're making chocolate mousse or frosting, we will often rely on cocoa powder.

And in order to sort of unlock all of the flavor that's in those cocoa solids, we found it's really important to do a technique called blooming. So a lot of old fashioned recipes that might call for cocoa powder - let's say you were making a cupcake - you would just add it with the flour and the other dry ingredients and, you know, add it at the end.

We find that that is not sufficient. What you really need to do is pour hot liquid - it can be water, coffee is great, brewed coffee - over the cocoa powder in a bowl to dissolve the cocoa powder fully and sort of unlock all the flavor that's trapped inside of those cocoa solids. And then you can use that cocoa powder in the cake batter.

You - you know, add - that's basically the liquid ingredient. Rather than adding milk which you would usually do at the end of making a cake or a cupcake along with the dry ingredients, you're alternating adding this bloomed cocoa along with the flour. And it's just a great way to make a super intense chocolate cake.

GROSS: Well, Jack Bishop, Bridget Lancaster, I want to thank you both so much for talking with us again.

LANCASTER: Thank you.

BISHOP: Thank you.

GROSS: Jack Bishop and Bridget Lancaster work on the public TV programs "America's Test Kitchen" and "Cook's Country" and have contributed to the new book "Cook's Illustrated: The Science of Good Cooking." You'll find recipes we've talked about on our website, freshair.npr.org. This is FRESH AIR. Transcript provided by NPR, Copyright National Public Radio.

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