Chef Jack Bishop Breaks Down ‘The Science of Good Cooking’

IRA FLATOW: This is Science Friday. I’m Ira Flatow. With Thanksgiving being just a few weeks away, I’m sure you’re getting a lot of advice– wanted and unwanted– about cooking for the holiday season.

So I’m just going to add a little bit more because it’s been our custom on this show to bring science to the table and the kitchen and offer you helpful suggestions based on cooking chemistry, like the trick to making a perfect dough for that pumpkin or apple pie– I think this one’s going to surprise you– or how to brine your turkey, how to whip up a perfect meringue.

Back in 2012, we talked with Jack Bishop from America’s Test Kitchen. They just released their book, The Science of Good Cooking. So we turned our studio into our own little test kitchen. And, well, here, have a listen.

We’re cooking in our New York studio. Welcome to Science Friday, Jack.

JACK BISHOP: Hi, Ira. Great to be here.

IRA FLATOW: We are surrounded by cooking stuff.

JACK BISHOP: I know. We don’t really– the wires and all the radio things with cooking things. Let’s hope it goes well.

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

JACK BISHOP: It’s a skillet. So I am going to re-teach you how to poach an egg. And you’re going to be successful.

IRA FLATOW: I’ve never done it in a skillet. Usually, I take the big pot of water. And that’s wrong, you’re saying.

JACK BISHOP: 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.

IRA FLATOW: All right.

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

IRA FLATOW: Ah. The acidity is going to help.

JACK 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.

IRA FLATOW: And you don’t want to boil it.

JACK BISHOP: And now I can turn my timer on.

[TIMER BEEPING]

And so by using residual heat, you are– no churning of the water, so you’re not going to blow apart the eggs. And you also get a really consistent result because if you’ve got a really powerful cooktop–

IRA FLATOW: Right.

JACK BISHOP: –it can be going much 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–

IRA FLATOW: Right.

JACK BISHOP: –we’re going to hope this induction burner cools down.

IRA FLATOW: [LAUGHS] And the vinegar helps coagulate the egg whites? The acid does that?

JACK BISHOP: Yes, we’re lowering the pH of the water, and that helps the proteins in the white to unfurl more quickly and bond together and hopefully protect the creamy yolk.

IRA FLATOW: [CHUCKLES] Could you use lemon juice instead?

JACK BISHOP: You could use lemon juice. I just use distilled white vinegar. You don’t want to use a colored vinegar.

IRA FLATOW: Ribght.

JACK BISHOP: Like, balsamic would give you lightly tinged whites, which may not be that attractive. But the vinegar will give a little bit of flavor to the eggs, balance a little the richness of the eggs, which is a good thing. So we like that.

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

JACK BISHOP: 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 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 5 or 6 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.

IRA FLATOW: [LAUGHS] Do you need a high brand vodka? You need first shelf vodka or you want–

JACK BISHOP: You’re not going to taste it. Because what happens is in the oven, when you’re baking the pie crust–

IRA FLATOW: Right.

JACK BISHOP: –the alcohol is going to cook off. We tested whiskey, rum, tequila.

IRA FLATOW: What a party that was, testing–

JACK BISHOP: Yeah, yeah. We were testing them, unfortunately, in the pie dough.

IRA FLATOW: I see.

JACK 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% alcohol, so that you are, in effect, where our recipe calls for 4 tablespoons of water and 4 tablespoons of vodka. But because of the alcohol in the vodka, it’s really the equivalent of 6 tablespoons of water, even though you get the sort of rollability of 8 tablespoons of water.

IRA FLATOW: What a trick.

JACK BISHOP: 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.

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

JACK 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 then we went into the kitchen and ran a series of tests. Our usual protocols, we’ll do one variable test. And so 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.

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

JACK 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.

IRA FLATOW: Did you decide that people needed to know more about science in the kitchen?

JACK BISHOP: We really feel like science is the key for many people to finally become a good cook.

IRA FLATOW: Hmm.

JACK BISHOP: 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.

IRA FLATOW: Right.

JACK BISHOP: Well, make–

[TIMER BEEPING]

IRA FLATOW: Oh, you–

JACK BISHOP: We’re slave to our timer here.

IRA FLATOW: [LAUGHS]

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

IRA FLATOW: OK.

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

IRA FLATOW: Right. Ooh, those look gorgeous.

JACK 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 a paper towel-lined plate. 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 still some in there. And as you can see, they came out fairly nice.

IRA FLATOW: Thank you. That’s great. Very little white left in the water.

JACK BISHOP: Very little white. I think you might want to, at this point, season them with a little bit of pepper.

IRA FLATOW: Well– wow.

JACK BISHOP: Well, make them taste a little better. And I think, Ira, you have the honors.

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

JACK BISHOP: You at least have to crack in and see.

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

JACK BISHOP: Yeah, I didn’t bring the Canadian bacon and English muffin. Now five minutes–

IRA FLATOW: Mm, mm.

JACK BISHOP: –gives you a runny yolk.

IRA FLATOW: That is good. OK, so [LAUGHS] a runny yolk. So 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.

JACK 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 runny yolk, five minutes is guaranteed to work.

IRA 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.

JACK BISHOP: 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 scramble it. You can fry it. You can poach it. But it’s a key ingredient in so many savory and baked goods.

IRA FLATOW: If you’re making scrambled eggs or you’re making just plain sunny side ups, is there a perfect temperature that you want? They heat the skillet up very hot, and 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?

JACK 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.

IRA FLATOW: Oh, you do?

JACK 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 a 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.

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

JACK BISHOP: A small pan.

IRA FLATOW: A small pan?

JACK BISHOP: Yeah.

IRA FLATOW: OK, a couple of egg lessons. And what’s the biggest mistake people make with eggs? Is it they used the wrong temperature, or are they just–

JACK BISHOP: That they don’t add enough fat, usually. In most egg recipes, what you’re doing is you’re coagulating the proteins. And the tendency is to then squeeze out the moisture.

IRA FLATOW: Right.

JACK BISHOP: 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 eggs that we’ve sort of beaten by hand, so that there’s a little bit of fat in there to ensure it’s sort of nice, soft, set. It doesn’t squeeze out the moisture in the eggs and make them tough.

IRA FLATOW: Cubes of frozen butter in the omelet. I’ll have to remember that because I love to make omelets. 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?

JACK 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.

IRA FLATOW: Yes.

JACK 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% water. And the goal is to preserve that natural moisture.

And by changing the shape of the proteins, it’s 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 in 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%–

IRA FLATOW: Wow.

JACK BISHOP: –which is really significant.

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

JACK 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 1/8 of a teaspoon per serving. So it’s about the same if you buy a kosher chicken or if you buy a Butterball turkey that’s been injected with salt. You wouldn’t brine those because they already have about that level of salt in them.

IRA FLATOW: All right, we have another wonderful in-studio demonstration. And we’re going to talk about– what have you got here? I’ll let you explain it.

JACK 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 take a bowl and start whisking and see who can make better progress.

[WHISKING]

IRA FLATOW: Come on.

JACK BISHOP: Now, I know you’re going to say–

IRA FLATOW: I used to be good at this, but this is not working. [CHUCKLES]

JACK 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–

IRA FLATOW: I got nothing. [LAUGHS]

JACK BISHOP: Yeah, you have 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–

IRA FLATOW: You dirty rat. [LAUGHS]

JACK BISHOP: Yeah. The point here is that if you get even a teeny bit of fat– and that fat 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.

IRA FLATOW: No. I was really surprised because I’m pretty good at making meringue sort of thing. Or if I make an omelet, I make the egg yolk separate and the whites and put them back together. Nothing.

JACK BISHOP: Nothing. And so it’s a really delicate kit operation. You are taking a couple tablespoons of liquid whites and a lot 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.

IRA FLATOW: So you want to make sure that it’s a very clean bowl. And you haven’t put butter or something in it beforehand.

JACK 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.

IRA FLATOW: What about the temperature of the bowl? I mean, I’ve heard people say you maybe have a cold bowl, or the egg yolk should– the white should be cold. What’s with that?

JACK 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.

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

JACK 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. The microwave sort of came and went. And people use a microwave to warm coffee, but they don’t really cook in a microwave. And so the technology, even though 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.

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

JACK 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.

IRA FLATOW: But all of Italian cookery is based on using olive oil.

JACK BISHOP: Well, it’s long– I mean, yes, most of that olive oil that– I mean, my Italian grandmother would sauté in it, but she was using refined olive oil.

IRA FLATOW: Oh.

JACK BISHOP: And so 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.

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

JACK BISHOP: Well, if you’re going to be cooking, yes. 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.

IRA FLATOW: Peanut oil? Peanut oil?

JACK 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.

IRA FLATOW: Is there one oil healthier? The unsaturated oils that’s–

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

IRA FLATOW: Jack Bishop, chef and senior content advisor at America’s Test Kitchen. He cooked with us in studio back in 2012 when they released their book, The Science of Good Cooking. And if you liked those tips, we’re going to have some more for you next week. As you get ready for your big holiday meals, we’ll have more fun food science.

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