Short Wave - Wok This Way: A Science Cooking Show

Episode Date: June 13, 2022

What's the most versatile pan in the kitchen? According to chef and cookbook author J. Kenji López-Alt, it's the wok! And along with spices, he sprinkles science explainers into his writing. Today's episode is just that — the science of the wok in action. He and host Emily Kwong talk about how to choose, season and cook with one, and why its unique shape makes it so versatile. Plus, we hear how Emily fared cooking one of Kenji's dishes from his new cookbook The Wok. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

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All right, here's our show. You're listening to Shortwave from NPR. Today on Shortwave, we have cooked up something special for you, literally. The people on peppercorns are splitting. Like they're exploding from the heat. Making delicious food and sharing it with people is something that I love. And you know who's phenomenal at this? Kenji Lopez-alt.

Like I literally cooked two different dishes this morning. One of them was pat-crapouse, so like Thai pork with basil, and the other one was Mapo tofu. Japanese-style Mapo tofu. Kenji has a metaphor to describe his cooking philosophy. He compares tackling a new dish to navigating a new city. And you can just stand there and walk down the street staring at your phone and turn when it tells you to turn. But you won't really have a understanding of what the city is like, of how you got there, what the neighborhood is. That's what following a recipe is to him.

Yeah, it will take you from point A, wrong ingredients, to point B, the final dish. And you know, that's fine for some people. But once you start to understand sort of technique and science, that's more like being even a map. I can take whatever root I feel like taking or I can wander around. And as a cookbook author, Kenji has thought a lot about this, how to teach people science-guided techniques to cook in new ways. It allows you to sort of plan your own route and take charge of your own cooking. And now he has written a book all about his favorite page. in the kitchen, the walk.

The walk that I have in my kitchen, I bought it when I was in college, so 20-something years ago. And for the last 20 years, Kenji's walk has had permanent residency on his stovetop. He cooks with it multiple times a week. I've been with my walk longer than I've been, longer than I've known my wife. In his book, aptly titled The Walk, Kenji Lopez-Alt explores recipes and techniques in detail, sprinkling science into his cooking directions. So today on the show, we're going to light those burners and pull out the fancy oil for the coolest pan in the kitchen, according to science. It's the most versatile pan in the kitchen.

I'm Emily Kwong, you're listening to Shortwave, the Daily Science podcast from NPR. Okay, Kenji, producer Burley McCoy and I did some cooking on our own to prepare for this interview, and we wanted to start with some walk basics. Do you know why the shape of the walk enables it to be the most versatile pan in the kitchen from like a scientific standpoint? Yeah, well, so the shape of a walk is really designed to encourage evaporation. So it has like a very wide surface area. It has a lot of cooking surface because it's so conducive to evaporation because you have so much surface area and because the shape of it allows you to toss. And so at least when you're stir-frying, you're looking for very dry heat.

So tossing and the evaporation that comes with that shape and the action of tossing is what allows you to do that. And what allows you to get that sort of specific concentrated flavor. One of the techniques you tell people about in the book is just simply pushing things up the sides of the walk because those sides are cooler. And I hadn't really thought about that how the walk has different zones of heat, which allows for food to stay at different temperatures, which is really not the same with a linear pan. So if you put food in a flat pan and you shake it, it ends up being in a sort of thin, even layer, right? And that's good when you're like searing a bunch of meat and you want all the steaks to sear evenly. You want there to be even heat across the whole surface. Whereas at the walk, you have this very intense heat at the very bottom,

and then it gets steadily cooler as it goes up the sides. So, for example, in the book, there's a recipe for Pad Thai, right? Where you start by cooking aromatics and then cooking the noodles and sauce, and then once the noodles are hydrated, you push them up the side and clear out the space in the bottom. And so the noodles don't continue to overcook, but the bottom gets really hot so that you can then fry an egg, you can push that egg up the side, you can sear shrimp. So you can do all these things in this one hot zone,

in the bottom of the walk without overcooking the ones that you've already cooked. You know, you make some really specific recommendations for home cooks buying walks and just want to spend a minute on your suggestion of a carbon steel walk, which you say has the highest volumetric heat capacity. What does that mean? Why is carbon steel optimal? Well, heat capacity is essentially the amount of heat energy a specific material holds per unit temperature, right? So if you think about your pan as a bucket that's storing energy, right? So

when you turn on a burner, you're essentially turning on a tap that's filling that bucket at a certain rate, right? And these buckets, they all leak, right? Your heat is going to be escaping into the kitchen. And once you put food in it, you're very rapidly pouring some of that energy out straight into the food, right? And so you want your pan to be able to hold a certain amount of heat before, so that, so that you're not relying just on the heat input of the stove. You want there to be this balance between the amount of energy that the pan can store so that you get some nice searing at the beginning and some nice really high heat at the beginning. But you also want to be able to adjust the heat rapidly up and down because there are many

recipes where you start really hot and then you bring the temperature down and then you bring it back up at the end to reduce the sauce, et cetera. So you want the pan to also be reactive. So carbon steel is good because it stores a good amount of energy, but it can be actually manufactured thin enough that it's still going to be reactive as well. And you say it's rare in Western cooking. that you find yourself in a recipe going from a simmer to a sear to a gentle bubble in a few minutes. But in a lot of non-Western cooking and Asian cooking, that happens all the time.

Yeah, exactly. Yeah. Lastly, we're in camp non-stick walk only. Yes? What's that? Oh, oh, no. Sorry. What am I saying?

What's the opposite of a non-stick walk? A non-stick walk? A stick walk? I don't know. A sticky walk? We're in camp. Avoid non-stick. Yeah, that's that.

That's what it is. Yeah. You say in the book, do not buy a nonstick walk. Yeah, avoid nonstick. You want that walk to be sticky. Why? Well, it's mainly because for many recipes, you're going to be heating the walk up very hot at the beginning in particular. So you might be heating the surface of the walk up to five or six hundred degrees. And nonstick coatings don't withstand temperatures that high. They tend to break down. And so some of them will actually start smoking and they'll turn it to these horrible carcinogenic things that get into the air, you know, at temperatures above 450 degrees or so. And so non-stick coatings generally are not tough enough to withstand that kind of thing. Mm-hmm. Yeah. Kenji, I recently had the DC contingent of Team Shortwave Over for dinner and we

cooked two dishes from your book. Okay. And, you know, I used a walk that I own that's already seasoned. when you purchase a walk before you use it, you talk in the book about seasoning it. Basically, you heat the walk over a flame until it turns almost a bluish black color, and then you dry it and coat it with oil. Why should you not skip this step? Why should you take the time to season your walk before you use it? Well, so there's a couple things. So first of all, like when you buy a carbon to do a walk, typically it comes coated with a layer of machine oil, like non-edible oil.

so you definitely want to get that out. The other reason is that, so when you heat your walk up, when you heat the bare carbon steel in the presence of oxygen, it forms black oxide, which is that black coating that you're getting, and that imparts certain non-stick qualities to it. So that's what's going to make it so that you can stir fry in it without things caking onto it. So, you know, nothing horrible is going to happen if you don't do that.

It's just going to be, your walk is just not going to have that layer of protection that makes it non-stick. And it also protects the metal so that it won't rest as easily. etc. And then finally, you know, if you're really going for certain dishes, there's that walk hay flavor, the breath of the walk, that kind of smoky flavor. So that's part of it as well. Thank you. You're helping us be better walk owners and users. So Kenji, we made your favorite dish, Maputou. What does the Maputouin mean to you? So, okay, so I grew up eating the Japanese version of Maputof. So Maputou is a Sichuan dish, right? From

the Sichuan province in China. But it came to Japan in the 70s, and my mom learned how to make it. And then, you know, when I was growing up in New York, my mom would make Mapo tofu. And what she would do is she would make dumpling filling, right? And so me and my sisters would then make dumplings using this filling, beef-based filling.

And then whatever leftover filling there was, that would become the beef part of the Mapo tofu. So she would always have that garlic and ginger and scalyons and stuff in it. And so she would stir-fried that and then season it with soy. The Japanese version is soy sauce. sauce and sometimes miso paste, Miran, and then soft tofu. It's, yeah, it's always been one of my favorite things. And it's a comfort food growing up.

And, you know, I make it for my kids now. That is so lovely. Kenji, we want to play you a little audio of Burley and I making your Mapu tofu and tasting the final dish. This is the tofu and Mapu Tofu right here. And it's just going to gently simmer in these sauces. Hmm. This did not turn out right.

The other dish did. This did not. Mm-mm. It's wrong. What was wrong with it? So I'll tell you what happened. Okay. Here's what happened.

Okay? I had, um, Doe Banjang, like, sauce, but not paste. Okay. So there were these other flavors in the Dolbon Zhang. Okay. which is different. Yes. And I was like, oh, no, this is not the same.

And then I was like, okay, remember what Jake Henji Lopez-Alt would say? Cooking is a map, not Google, so just roll with it. And so the flavors didn't taste quite right. And so I tried to balance them by adding some more salt to kind of just mellow out the funky flavors and the sauce. Okay. And over time, it kind of figured itself out and tasted right. Well, good. I'm glad it worked out over time.

And my guests clearly didn't mind. They liked it. Yum. Yeah, ground beef. This is Maput tofu. What excites you about what's happening at the intersection of science and cooking right now? I don't know. I've got two little kids, and so I don't pay much attention to much outside my house.

Sure. What excites me is that, I mean, the intersection of science and cooking is that my daughter loves experimenting in the kitchen. And we talk about science while we're cooking. So that's the most exciting thing for me right now. I don't know about the rest of the world. That's beautiful, Kenji. Thank you so much for bringing all this information,

putting it all together into one unbelievably cool book. It was so much fun to work through it and to learn from it and to talk to you today. Yeah, it was good to talk to you too. And just a quick reminder, give us feedback on Shortwave by filling out our podcast survey. Now is really your chance. Go to npr.org slash podcast survey. This episode was produced by Burley McCoy. It was edited by Rebecca Ramirez and Gabriel Spitzer,

and fact-checked by Rachel Carlson and Margaret Serino. The field engineer was Natasha Branch, and the audio engineer was Josh Newell. Giselle Grayson is our senior supervising editor, Beth Donovan is our senior director, and Anya Grunman is our senior vice president of programming. I'm Emily Kwong. Thank you so much for listening to Shortwave, the Daily Science Podcast from NPR.