Hey Professor! Science and Cooking: Thanksgiving Edition

With Thanksgiving around the corner, FM sat down with Harvard School of Engineering and Applied Sciences’ Michael P. Brenner and David A. Weitz, who teach SPU 27: Science and Cooking, for advice on how to cook the perfect Thanksgiving dinner at the molecular level. 

How would you use modernist cuisine and your knowledge of materials science to cook the perfect turkey?

Weitz: I think the best turkey is still cooked the traditional way, but if you look, Nathan Myhrvold is the guru of modernist cuisine. He’s the former CTO of Microsoft who now has a food lab. He has fancy ways of cooking turkeys, so I’d look up what he does.

Brenner: Cooking involves transformations of food. Like for Thanksgiving, you have to cook the turkey so that the inside of the turkey is well cooked, as well as the outside is properly cooked. The constraints for those things are really different. Most people would want the inside of the turkey to be cooked at 175 degrees Fahrenheit, but the outside has to be cooked much hotter than that, because if it doesn’t it won’t brown. You won’t get that crispy brown flavor that tends to make things taste delicious. There’s a tension between getting the inside to cook at a temperature at you want, which is much lower than the outside in order to get the thing to work. It’s sort of like chess; recipes tell you ways to do this, but if you understand how heat in this way moves through food, then you can sort of think through it on your own, and that can certainly help make you a better cook.

Any other advice for major Thanksgiving staple foods?

Weitz: Cranberry sauce. That’s an interesting material—that’s making a gel out of cranberry. Really good cranberry sauce should be able to cook without a lot of pectin and still get it to gel. There’s pumpkin pie, right? Making more of a foamy pumpkin pie—that would be sort of interesting.
What is your favorite Thanksgiving food?

Weitz: I mean, a good turkey, what else? That’s the way you have to have it.

Brenner: I’m not a great fan of Thanksgiving. […] I don’t actually eat meat. I’m interested intellectually in cooking turkey. None of the traditional foods, I must admit, I’m a great fan of. Sorry.

What is the kind of research that you do and, if possible, how does it relate to cooking?

Weitz: It’s not directly related to cooking, but it’s as close to cooking as most research comes. Rheology tells you the mechanical properties of something. When you chew on something: that’s the mechanical properties, that’s how things feel—not necessarily taste, but feel. It’s probably best quantified by something like rheology. I’m very interested in the structure of materials that are like many foods: gels, foams, emulsions. So I know a lot about that type of structure. The foods that we eat, especially by high-end chefs, are often like that.

Brenner: One of things that I’ve been interested in lately is trying to figure how to design materials that assemble themselves and do cool things like self replicate. We make mathematical models to try to understand constraints under which such things can happen. And I also make models of things which are sort of ordinary. For example, it turns out no one knows how a drop of fluid splashes on a solid surface. Everyone knows that it happens, but no one really understands why, if you think about it. So we sort of write down the equations of motions that correspond to such things and try to figure out why they work as they do. For me, the cooking class makes sense in that context because it’s really about how to understand phenomena that occur in daily life when you cook. Although I don’t study cooking professionally, I do try to understand things in simple terms.

Are you interested at all in the molecular gastronomy movement?

Weitz: So honestly most people who are interested in molecular gastronomy are a bunch of French scientists. Chefs themselves don’t like the term themselves. Modernist cuisine is a more acceptable terminology, so I sort of side with the chefs.

Does this knowledge help cooking at home?

Weitz: It should, but I don’t cook. That’s the beauty of the class is that we collaborate with these wonderful chefs. I do the science, they do the cooking. I believe in letting the experts do what the experts do—what they are experts at.

Brenner: I do cook and I do use these principles. As soon as you understand why it is you are doing things, then it makes it much easier to cook, because you don’t have to follow the recipe religiously. If you don’t know how the recipe works, then you have to follow the recipes religiously, because you don’t know which steps you can ignore, right? If you understand why the steps are there, then you how you can modify it and still have the thing work.