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Science & Environment

Chef Jack Bishop on 'The Science of Good Cooking'


This is SCIENCE FRIDAY; I'm Ira Flatow. Chefs are like, a little bit like golfers: They're always looking for tips to improve their game. So as you prepare for the last big party of 2012 or the first one of 2013, we have some gastronomical tips to improve your cooking and baking skills and the reasons behind why they actually work.

What's the trick to making a perfect pie dough? We have the answer to that, and I think it's going to surprise you. How do you poach an egg without turning all the boiling water into a swirly mess of egg whites? We're going to teach you how to do that, too. It all boils down to this: If you want to unlock the secrets of good cooking, you have to understand the science.

That's the idea behind the newest cookbook from America's Test Kitchen, "The Science of Good Cooking." It's really a great cookbook to have in your arsenal because it meticulously explains what works, what doesn't and why. And my next guest is here to give us a glimpse of some of the Test Kitchen's more surprising finds.

Jack Bishop is a chef and cast member on the cooking shows "America's Test Kitchen" and "Cook's Country." He is the editorial director at America's Test Kitchen and contributed to the show's newest cookbook, "The Science of Good Cooking," and he joins us here. We're cooking in our New York studio. Welcome to SCIENCE FRIDAY, Jack.

JACK BISHOP: Hi Ira, great to be here.

FLATOW: We are surrounded by cooking stuff.

BISHOP: I know, we don't really - you know, the are wires and all the radio things with cooking things. Let's hope it goes well.

FLATOW: Well, let's get right to the first thing. We have a pot of, a simmering pot of water here. Well, it's not actually a pot, is it?

BISHOP: It's a skillet. So I am going to re-teach you how to poach and egg, and you're going to be successful.

FLATOW: In a - I've never done it in a skillet. Usually I take the big pot of water, and that's wrong, you're saying.

BISHOP: You're - the big problem with the saucepan, if you're doing a narrow pot, it's a long way down for the egg to drop into the pot. A lot of people crack it right on the side of the saucepan, and then it falls apart. I mean, the challenge when you're poaching an egg is to keep the white to surround the yolk, so you end up with a set white and a creamy yolk.

FLATOW: All right.

BISHOP: The skillet makes it much easier. So I've got boiling water in a 12-inch skillet. You can use a smaller skillet if you'd like. And I - the trick here is we're going to gently coax the eggs in. So I've got two teacups, one in each hand. They have little handles on them that allow me to get close to the water, and I've got two eggs cracked into each, and I'm just going to turn them ever so gently into the skillet.

And I'm going to add a little bit of vinegar. The pH is going to help...

FLATOW: Ah, the acidity is going to help.

BISHOP: And a little salt really just for flavor, and I'm going to turn off the heat. The other big mistake people make is they boil, and the turbulent water will cause the eggs to break apart.

FLATOW: You don't want to boil it.

BISHOP: And now I'm going to turn my timer on. And so by using residual heat, you are sort of - no churning of the water, so you're not going to blow apart the eggs. And you also get a really consistent result because, you know, if you've got a really powerful cooktop, it can be going much sort of faster coming back to the boil, and we're basically just doing it with residual heat.

If you were doing it on a real cooktop, we're on a little induction burner, you might even slide it off the burner onto a cool burner. We don't have a cool burner, so we're going to hope this induction burner cools down.

FLATOW: And the vinegar coagulate the egg whites, is that - the acid does that?

BISHOP: We're lowering the pH of the water, and that helps the proteins in the white to sort of unfurl more quickly and bond together and hopefully protect the creamy yolk.

FLATOW: Could you use lemon juice instead?

BISHOP: You could use lemon juice. I just use distilled white vinegar. You don't want to use a colored vinegar, like balsamic would give you lightly tinged whites, which may not be that attractive. But, you know, the vinegar will give a little bit of flavor to the eggs, balance a little of the richness to the eggs, which is a good thing. So we like that.

FLATOW: Well, while we're waiting for the eggs to cook, let's talk a little bit about more in your book. What is the secret - I heard, I read the secret to the perfect pie crust, and it's something I would have never imagined. Tell us what that is.

BISHOP: You know, pie dough seems like it should be simple. It's really just four or five ingredients. There's flour, salt, a little bit of sugar, fat and ice water. The problem is that most recipes are engineered to use a minimum amount of ice water, and the theory is that when the water is mixed with the flour, you are activating the glutens, and you're developing this sort of strand of protein network, which is great if you're making bread. It's what gives bread great chew.

But in pie dough, it will make it fairly tough, and so you use as little water as possible in order to just get the flour to sort of hold together with the fat. The problem is most recipes don't use enough, and so you go to roll out the dough, and it's cracking, it's really difficult to manage, and most cooks end up adding more water than the recipe says.

A typical recipe for a double-crust pie will call for five or six tablespoons of water, but it's really not quite enough. So we said: What is wet that could give us more moisture so that we could hydrate the dough and make it easier to roll out with less cracking but would not form gluten? And it turns out that alcohol does not form gluten when it's mixed with flour.

And so we replaced half of the ice water with chilled vodka in our pie dough.


FLATOW: Do you need a high brand vodka, first-shelf vodka, or...?

BISHOP: You're not going to taste it because what happens is in the oven, when you're baking the pie crust, the alcohol's going to cook off. We tested whiskey, rum, tequila...

FLATOW: What a party that was testing...

BISHOP: Oh yeah, and we have - we were testing them, unfortunately, in the pie dough.

FLATOW: I see.

BISHOP: You cannot taste the difference, really, between all of them. The important thing is to use something that's 80 proof, that's 40 percent alcohol, so that you are in effect, where our recipe calls for four tablespoons of water and four tablespoons of vodka, but because of the alcohol in the vodka, it's really the equivalent of six tablespoons of water, even though you get the sort of rollability of eight tablespoons of water.

And it seems like it's a really small trick, but it makes it so much easier to roll out the pie dough, and it's really flaky, and it's really tender.

FLATOW: So does this come about from actually testing things in the Test Kitchen, the ideas and recipes?

BISHOP: The Test Kitchen has about 25 people who work full-time who are trained cooks. We also have a science editor. And so this was one of those questions that we discussed with our science editor. We said: What's wet that you could add to pie dough that's not going to form gluten? And he said, well, alcohol. And, you know, then we went into the kitchen and ran a series of tests.

Our usual protocols will do sort of one variable test. And so, you know, we'll do the standard recipe with water, and then we'll do variations, in this case with vodka, and easy to tell the difference.

FLATOW: So people who have picked up their ears now from hearing this, what's the recipe, how much vodka for how much water?

BISHOP: So you want to use half-water and half-vodka. If you have a favorite pie dough recipe that calls for ice water, just replace half of the water with chilled vodka. It's really important that the water is cold so it doesn't melt any of the fat in the dough.

FLATOW: Wow, talking with Jack Bishop, chef and cast member on the cooking show "America's Test Kitchen" and "Cook's Country," also contributor to Cook's Illustrated "The Science of Good Cooking: Master 50 Simple Concepts to Enjoy a Lifetime of Success in the Kitchen." A great book. Why did you decide - did you decide that people needed to know more about science in the kitchen?

BISHOP: We really feel like science is the key for many people to finally become a good cook. You know, I think there's a sort of generational issue that many people didn't grow up in homes where they could watch cooking. And so how do you learn how to cook? And a lot of people get frustrated because they make mistakes and think oh, I shouldn't be making mistakes. Well...


FLATOW: You'd better...

BISHOP: We're a slave to our timer here.


BISHOP: So that means our poached eggs, you're going to have to wait for my answer on this one.


BISHOP: So I'm going to take the lid off of the skillet.

FLATOW: Right. Ooh, those are gorgeous.

BISHOP: I'm going to now reach in with a slotted spoon to try to take out each of the four poached eggs. I'm going to transfer them to paper-towel-lined plates. The paper towel is going to soak up the extra water that is still on them. The slotted spoon is getting rid of most of the water, but there's still some in there.

And as you can see, they came out fairly nice.

FLATOW: Thank you, that's great, very little white left in the water.

BISHOP: Very little white. I think you might want to at this point season them with a little bit of pepper, make them taste a little bit. And I think, Ira, you have to do - you have the honors.

FLATOW: Somebody has to take over the show while I eat here.

BISHOP: You at least have to sort of crack and see...

FLATOW: All right, crack one open. This looks good because poached eggs are among my favorite food. I need a little English muffin here, I think.

BISHOP: Yeah, I didn't bring the Canadian bacon and English muffin. Now five minutes gives you a runny yolk.

FLATOW: That is good. OK (unintelligible)...


FLATOW: A runny yolk, do if you overcook it, it's going to get a little harder, and five minutes works. But the secret, as you said, is not boiling the water but simmering it...

BISHOP: And the five minute works whether you're doing one egg or eight. If you're going to do more than eight, you might want to go to six or seven minutes because there are so many eggs in the water. And of course if you want a more set yolk, you could go an extra minute. But for a sort of runny yolk, five minutes is sort of guaranteed to work.

FLATOW: And eggs are a good place to start if you want to learn about the science of cooking, right? There are so many things you can do with eggs.

BISHOP: It's - you know, they don't call it the incredible egg for nothing because you really can do so many things, not just different cooking methods. You can, you know, scramble it, you can fry it, you can poach it, but it's a key ingredient in so many savory and baked goods.

FLATOW: If you're making scrambled eggs, or you're making just plain sunny-side-ups, is there a perfect temperature that you want? People throw it in, you know, they heat the skillet up very hot, and then they throw the egg in, and it's sizzling. Does that wreck the egg, or do you want to cook it on a lower temperature?

BISHOP: For scrambled eggs, the key is fairly high temperature because what you're trying to do is convert the water that's in the eggs - and we also add some half-and-half to our scrambled eggs.

FLATOW: Oh, you do?

BISHOP: Yeah, the fat keeps them tender, and the additional moisture creates steam, which is what makes them fluffy and light. And so if you're using low temperature for scrambled eggs, if you want really fluffy, light eggs, you're not generating enough steam. So you want fairly high temperature, and you have to work really quickly because you don't want them to get tough or brown.

For fried egg, we actually heat the pan over low for 10 minutes, trying to get a really even heat, then crank it up so there's no hot spots, and add the fried egg.

FLATOW: Should you use a smaller pan, like an omelet pan, for one or two eggs, or should you use a bigger pan?

BISHOP: A small pan is much better, yeah.

FLATOW: A small pan, and that will take - an omelet pan, which is a lot thicker metal, will take a longer time to heat up at that lower temperature.

BISHOP: And it will be a much better job.

FLATOW: OK, a couple of egg lessons. What's the biggest mistake people make with eggs? Is it they use the wrong temperature, or they just don't treat it with respect?

BISHOP: Yeah, that they don't add enough fat, usually. In most egg recipes, what you're doing is you're coagulating the proteins. And, you know, there the tendency is to then squeeze out the moisture. And if you add a little bit of fat, whether it's a little half-and-half in your scrambled eggs - when we make an omelet, we add little cubes of frozen butter to the scrambled - you know, to the eggs that we've sort of beaten by hand so that there's a little bit of fat in there to ensure a sort of nice soft set that doesn't squeeze out the moisture in the eggs and make them tough.

FLATOW: Cubes of frozen butter in the omelet. I have to remember that because I love to make omelets. We're talking with Jack Bishop about Cook's Illustrated "The Science of Good Cooking," our number 1-800-989-8255. When we come back, we're going to talk about another secret, and that is how to fluff up some egg whites. There's the right way to do it and the wrong way to do it. I guess it'll be a meringue sort of thing.

And if you want to make - go along with us, call us at 1-800-989-8255. We're on our website at sciencefriday.com. We'll be right back after this break with Jack Bishop. Stay with us.


FLATOW: I'm Ira Flatow; this is SCIENCE FRIDAY from NPR.


FLATOW: This is SCIENCE FRIDAY. I'm Ira Flatow. We're talking this hour about the science of good cooking. My guest is Jack Bishop, chef and editorial director at America's Test Kitchen and contributor to "The Science of Good Cooking: Cook's Illustrated: Master 50 Simple Concepts to Enjoy a Lifetime of Success in the Kitchen."

If you need a basic kitchen book, this is it, you know, how do I do this, how do I do that, and you want to have basic recipes and the right way to do it, boy, this is a great book. There are a lot of great tips in the book. And I want to dive into one in particular, which is the case for brining meat. What is brining meat?

BISHOP: So brining meat is the solution to overcooked lean protein. So we're talking about the white meat in chicken or turkey, lean cuts of pork like a pork loin or pork tenderloin. There's very little fat, and it can really dry out and be chalky and tough. We've all had a horrible Thanksgiving turkey.


BISHOP: The solution next year is to brine the turkey, and you are putting the protein in a bucket with a solution of salt and water. And what is happening is that the salt is changing the structure of the muscle fibers and creating spaces that can then trap the natural juices in meat.

Most meat is 75 percent water, and the goal is to preserve that natural moisture, and by changing the shape of the proteins, actually the sodium and chloride ions have negative and positive charges, and they're changing the way the mosaic of charges on the proteins are working, and you are getting more water to be held into the meat, its own natural juices, in addition to obviously some of the water that's in the brine makes its way into the meat.

And basically we found in side-by-side tests you can cut moisture loss by 25 percent, which is a really...

FLATOW: Doesn't it taste salty, the meat, when you take it out?

BISHOP: You don't want to season it too much. The average amount of salt, if you brine it, is going to be about an eighth of a teaspoon per serving. So it's about the same if you buy a kosher chicken or if you buy a Butterball, which has been injected with salt. You wouldn't brine those because they already have about that level of salt in them.

FLATOW: Yeah, when they kosher a turkey, they already put the salt and whatever in there, that sort of thing, koshering it. 1-800-989-8255. A tweet came in that says: How do you hard boil an egg so that it peels easily? What's the secret to that?

BISHOP: Well, the secret to hard boiling an egg is much like poaching, which is to use residual heat. So you bring the eggs in the water to a boil, turn it off, take it off the burner, and it's exactly 10 minutes because then it...

FLATOW: Exactly.

BISHOP: Exactly 10 minutes, and then drain out the water and then crack the eggs in the empty pot and sort of, you know, break up the shells. And then put them in ice water. The ice water will cool them down so that they won't continue to cook, and you won't get that green ring, and the water gets under the cracked shell and makes it much easier to then peel off the shell if you put them in an ice water bath for 30 seconds to 60 seconds.

FLATOW: All right, we have another wonderful in-studio demonstration that we're going to talk about, what's the right way to - or what have you got here? I'll let you explain it.

BISHOP: I have two identical bowls, two identical whisks. Inside each bowl are three egg whites. Now whipped egg whites are the secret to everything from soufflés to cakes. We are going to both take a bowl and start whisking and see who can make better progress.


BISHOP: Now I know you're going to say...

FLATOW: I used to be good at this, but this is not working.


BISHOP: Well, so what we're doing is we're creating a foam here, and as you can see in my bowl, Ira, I'm already...

FLATOW: I got nothing.


BISHOP: Yeah, you got nothing. I actually kind of did something not very nice to your bowl: I sprayed it with a little bit of Pam cooking spray, and...

FLATOW: You dirty rat.


BISHOP: The fat is - the point here is that if you get even a teeny bit of fat, and that can be leftover grease from not washing the bowl very well to the fat from the yolk, it will prevent those whites from whipping properly, and you really can't get a stable foam.

FLATOW: No, I was really surprised because I'm pretty good at making a meringue sort of thing, or if I make an omelet, I make the egg yolks separate than the whites and then put them back together - nothing.

BISHOP: Nothing, and so, you know, it's a really delicate operation. You are taking, you know, a couple tablespoons of liquid whites and a lot of sort of horsepower in your arm and turning this into a stable foam. And if there's a little bit of fat in there, it will cause the foam to collapse or really even just prevent the foam from forming.

FLATOW: So you want to make sure that it's a very clean bowl, and, you know, you haven't put butter or something in it beforehand.

BISHOP: And never use plastic. It's almost impossible to get a plastic bowl really clean. There's always traces of fat in plastic. So I had stainless steel bowls here. Glass is fine. But avoid plastic because it just doesn't really get as clean as it should.

FLATOW: What about the temperature of the bowl, or, I mean, I've heard people say you need to have a cold bowl, or the yolks, the whites should be cold. What's with that?

BISHOP: It is much easier to separate the yolks when they're cold because the yolks are much firmer and taut, and the eggs will not separate. So separate the eggs right from the refrigerator. In terms of the whipping, whether those whites are at room temperature or cold isn't going to make much difference in the ability to create a foam.

FLATOW: All right, I'm going to go to the phones and take one call here, see if we can get a phone call in. Let's go to Jeff(ph) in Pittsburgh. Hi Jeff.

JEFF: Hi Ira, how are you?

FLATOW: Hi, how are you?

JEFF: I'm well, thank you.

FLATOW: Go ahead.

JEFF: I have a question about pizza dough. I'm hoping that maybe the vodka solution might work for it. My pizza dough always turns out heavy like a lead brick, and I'm not sure if it's because I'm overworking the dough or not letting it sit long enough. Is there any chance that the vodka might tenderize it or help it rise?

FLATOW: Should you put vodka in your pizza dough also, besides your...?

BISHOP: No, if you drink the vodka, it might make the pizza dough taste better...


BISHOP: But the vodka is not going to improve pizza dough. Two things is to make sure that you have enough water. If you don't have enough water, the dough won't rise properly. The second thing is to try letting rise in the refrigerator. We find that a lot of bread doughs do much better, you know, under conditions called cool fermentation, and really let it go even overnight.

You know, make the dough before you go to bed, or make it first thing in the morning, and then throw it in the refrigerator and let it just rise gently. You often get a much better result. You get sort of more bubbly pizza dough crust. So give those two things a try: a little more water and let it rise in the refrigerator.

FLATOW: Are there any new techniques based on science? I've heard people using vacuuming, they vacuum-pack the food before they cook it.

BISHOP: Yeah, I mean it's a really interesting time in food because in the world of professional cooking, in restaurants, there's so much science and technology. I mean, molecular gastronomy is really changing the way that a lot of chefs prepare dishes in restaurants.

At home, the technology is kind of the same old technology. You know, the microwave sort of came and went, and people use a microwave to, you know, warm coffee, but they don't really cook in a microwave. And so the technology - even though, you know, we spend a lot more on the equipment than we used to in our kitchen, it really is basically the same equipment with nicer finishes.

FLATOW: Let's talk a little bit about the different type of cooking oils. There's so many different ones. What's the science behind which type of oils to use for what purposes?

BISHOP: So the first thing you want to think about is are you going to be heating the oil, and if you're heating the oil, then the smoke point is hugely important. And in that case, you want an oil with a high smoke point because once the oil starts smoking, it's a sign that it's breaking down and degrading. And so olive oil, for instance, has great flavor, but because it's not fully refined, it has a fairly low smoke point. It's not really great for frying or sautéing.

Vegetable oil, soybean oil, corn oil, canola oil, those can withstand more heat, and...

FLATOW: But all of Italian cookery is based on using olive oil, isn't it?

BISHOP: As long - I mean yes, most of that olive oil - I mean, my Italian grandmother would sauté in it, but she was using refined olive oil. And so, you know, if you've got a really high-end extra virgin oil that's got particulate matter in it, you don't want to be frying in it because that means it's going to smoke at a much lower temperature.

FLATOW: So you use a worse grade of oil to fry in?

BISHOP: Well, if you're going to be cooking, yes. You know, for salad, I wouldn't use anything other than really good extra virgin olive oil. But for cooking, we use a lot of vegetable oil in the test kitchen.

FLATOW: Peanut oil? Peanut oil is good?

BISHOP: Peanut oil has a great high smoke temperature. It has a sort of nice flavor that it can add. Most of the flavors are really subtle, so the difference between corn and safflower and sunflower and canola are really very minor. The one thing is we don't like to fry in canola oil. We find that it gets a little fishy tasting, actually, when it's heated for really long periods of time when you're frying. So we don't fry in canola oil.

FLATOW: Is there one oil healthier, the unsaturated oils, that's...?

BISHOP: I mean, olive oil is probably - you know, and the canola oil get the best marks from the nutritionists. You know, I think we like olive oil except for super-high-heat applications.

FLATOW: Let's talk about America's favorite food, the hamburger. I mean, I saw some tips of America's Test Kitchen investigating the best way to make a hamburger.

BISHOP: Yeah, the biggest problem with hamburger is actually the meat. And so, you know, what you buy in the supermarket, there are two problems. One is you don't actually know what cut of meat it comes from, and so if you - you ideally want something with a fair amount of fat, from the chuck, short ribs make a super burger.

The second thing is the way it's packaged in that shrink-wrapping makes it almost impossible to get anything other than a dense hockey puck.

And so we actually grind our own beef. You only need a food processor. You freeze the meat, and then you can grind it in the food processor, and it makes a much tastier burger, more fat, and it's got a lighter texture, and it's not that dense heavy hockey puck that you get from supermarket ground beef.

FLATOW: Yeah. It's like the old days.

BISHOP: It's like the old days.

FLATOW: Going to the butcher, bringing the meat home, grinding it up.

BISHOP: Yeah. And there's nobody grinding meat in any supermarkets in America anymore.

FLATOW: They're all coming in with the meat ground already, yeah.

BISHOP: Yeah, it's been grounded in plants in the Midwest and then shipped all over the country, and that's really the problem.

FLATOW: I think I've seen that commercial. We're going to - I want to bring on another guest to talk about how our eating habits have changed with the invention of the fork and what's the single greatest achievement in cooking technology. Jack, you can have a seat.


FLATOW: Sit down. Make yourself at home because I hope you'll stick around for a few more minutes with us. Transcript provided by NPR, Copyright NPR.