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Friday, September 20, 2013

Using Science To Craft The Perfect Pie



Amy Rowat has a PhD in physics and has pioneered the use of food to teach sophisticated science concepts to non-scientists.

Rowat can also bake a mean pie. She shares some of her favorite tips with Here & Now.

What are the best pie tips that you’ve picked up — or that have been passed down to you?
Tell us on Facebook or in the comments.


  • Amy Rowat, professor of integrative biology and physiology at UCLA.




And now a few minutes on pie, which is all it should take, right? Easy as? But Amy Rowat, a professor of integrative biology and physiology with a PhD in physics goes deep on pies, using pie and other food to teach science at both Harvard and UCLA. She's been interested in both science and food since childhood. She's also doing serious research on cancer and says food science helps her understand cancer cells.

But this past spring, her students did an exhaustive study on pies. The result: a piece in The New York Times entitled "Science Builds a Better Pie." And since apple pie season is under way, let's find out more. Amy joins us from the studios at UCLA. Tell us more about how you came to use food in teaching.

AMY ROWAT: So I studied emulsions. I studied also yeast cells. And those are both topics that are really closely related to food. But I guess it was prior to my time at Harvard as a graduate student in Denmark where I was studying lipid membranes that I started to realize the intersection of the topics I was studying and the foods that we were eating. Then when I got to Harvard, we started out doing a lecture on pizza. Then we did chocolate to teach concepts like phase transitions, how things melt.

YOUNG: Well, I want to reach back to something you said - how might lipid membranes interact with food. Remind me what a lipid membrane is.

ROWAT: Lipid membranes are tiny, nanoscopic sheets of fat, essentially. And they're also widely used in food. So think about why you add mustard, for example, to a vinaigrette. You want to be able to stabilize the vinaigrette. You don't want your oil and vinegar to separate. And by adding a bit of mustard or garlic, which contains these lipid molecules naturally, that can help to stabilize a vinaigrette or your aioli.

YOUNG: Well, stay with the pies. People like to get their pies browned on the top. And I see an explanation that you gave in the New York Times, the Maillard reaction? Am I pronouncing it correctly...

ROWAT: Mm-hmm.

YOUNG: ...the chemical reaction?

ROWAT: That's right.

YOUNG: What is that?

ROWAT: That occurs between proteins and certain types of sugar such as lactose, which is commonly found in milk - heavy cream, for example. So by mixing or just brushing your crust with the milk or mixing it into an egg wash can help to promote browning reactions on your crust.

YOUNG: Staying with the crust, you say it's flour and water. And there's a molecular network, is that what you said, that forms? But you don't want there to be too much of a network because that will toughen the crust. And I understand that you discovered if you replace some of the water in your crust mixture with alcohol or vinegar, it'll stop that gluten formation?

ROWAT: Mm-hmm. And that was something that my students had picked up on, that people had written about previously using vinegar or vodka in a crust. But they explored rum and bourbon and many different types of alcohols. But in making a pie, you want to go for a flaky texture, and you want to somehow impede these networks of molecules from forming. And so a common way to do that is to add in some sort of fat.

ROWAT: Butter contains a lot of water. By putting the butter into the crust, you create - you can create these little pockets of gas because the water turns into vapor. People talk a lot about European butters and how they have a lower water content and they're so much better. But in fact one of the students in my class found that using American butter that has a slightly higher water content was actually helpful in promoting a flaky crust.

YOUNG: Amy Rowat, professor of integrative biology and physiology. We will post her "How To Build a Better Pie Through Science" article at Professor Rowat, thanks so much.

ROWAT: Thank you, Robin.

YOUNG: Who knew? You're listening to HERE AND NOW. Transcript provided by NPR, Copyright NPR.

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