Wok this way with Kenji López-Alt to learn the science behind stir fries

In his second cookbook “The Wok: Recipes and Techniques,” Kenji López-Alt crowns the wok as the most versatile pan in the kitchen. With the majority of people around the world cooking with woks at home, he debunks the common belief that the tool is for restaurant-use only. He has had the same wok since college and recommends a carbon steel wok that is 14 inches in diameter, at least one and a half to two millimeters thick, and with a flat-bottom.

Seasoning of a wok is much simpler than Western-style skillet, López-Alt says. Two things happen during the seasoning process of cast iron — forming black oxide and building layers of polymers with the heating and breaking down of oil. With a wok, the seasoning happens each time one cooks, and he uses soap whenever it’s needed. Keeping the wok dry is the most critical thing to remember.

He explains that The Georgia Institute of Technology conducted a study of the motion of people cooking in a wok with three distinct cycles in four phases, concluding that a stir fry should be called a “toss fry” as food is being tossed more so than stirred.

Mise en place is the most important part of a stir fry and for each recipe in the book, he makes recommendations of what bowls are needed before starting to stir fry. He also tends to use his wok for his stocks and braises.

The following interview has been edited for length and clarity.

KCRW: A lot of people are intimidated even buying a wok, let alone cooking with one. What should we look for?

Kenji López-Alt: I think one of the things that intimidates people about buying a wok is that they have this notion that a wok is really a restaurant tool, and that you need a restaurant-style burner, and that is not going to work on your home equipment, especially if you have something like induction or an electric stovetop. But that's not really the case. That idea is colored by the fact that [for] most of us in the West, our experience eating stir fried food … cooked in a wok comes from restaurants.

But the majority of people cooking with woks around the world are cooking at home. So you don't really need to worry about what kind of equipment you have at home. The majority of recipes that you're going to find for wok cooking can be done just fine on a regular burner. What I generally recommend is a carbon steel wok about 14 inches in diameter, which is good for around a family of four, at least one-and-a-half to two millimeters thick, so around 16 to 14 gauge. And unless you have a specific wok burner, I would recommend getting a flat bottom wok. That's what I use pretty much exclusively.

I think the other thing that freaks people out is the whole idea of seasoning and then cleaning the wok once you've acquired it.

I think it's the same fear that people have of cast iron pans. It's unfounded in cast iron pans, and even more so in woks, because the seasoning on a wok is actually much simpler than on a Western style skillet. In a cast iron pan, when you're seasoning, you're doing two distinct things. First of all, you're forming black oxide, which is what happens when you heat up cast iron or carbon steel and it comes into contact with oxygen and forms this black patina on it. … So every time you cook in it, you're taking oil and you're breaking it down, and it forms a polymer, a plastic-like substance that builds up in very thin layers over time. And that's what makes a Western-style cast iron pan or carbon steel skillet nonstick.

With a wok, you're really only concerned about that initial black surface. So you're not trying to build a thick layer of polymers and seasonings … especially because you're going to be cooking at very high heat and then suddenly adding liquids to it. You're going to be adding acidic ingredients, you’re going to be doing all these things that make it really difficult to build polymers anyway. But that's okay, because in a wok, the seasoning is really something you do each time you cook. So it has more to do with the way you properly preheat the wok and rub it with oil before each time you cook. And that's how you get a wok to be nonstick, which is a fundamentally different approach than what you would do for a Western skillet. I use soap to clean my wok whenever I need to. The only real thing that you have to be worried about is making sure that it stays dry. And aside from that, just cooking it is going to season it.

Kenji López-Alt uses the wok he cooked with in college and thinks outside of the box when making everything from stocks to braises. Photo by Aubrie Pick.

What are the four phases of a stir fry?

This is one of those things where you don't really have to know them in order to do them. I think what you're referring to is the study at the Georgia Institute of Technology, where David Hu, who’s a fluid dynamics professor, and his students used software to track the motion of people cooking in a wok. And what they found is that three times per second is the rate at which a stir fry cook at a restaurant will be tossing food in a wok, so it's pretty fast. Each one of those three cycles, there are four distinct phases.

The first one is where you're holding the handle of the wok, tilting it slightly away from you, and it's kind of pulled forward towards your body on the burner. In the second motion, you're pushing the wok forward away from your body, still keeping it tilted away from you. And then in the third motion, you start tilting the wok backwards and pulling it back towards you. And this is what causes the food to fly up the back of the wok and roll back towards you in a wave. And then in the final move, you're pulling the whole wok back towards you and catching the food again, and you're repeating that over and over and over. It's one of those things where it's interesting to see on paper and in slow motion. To actually do it, you have to get in the kitchen and really do it. A stir fry should really be called a toss fry, because it's much more about tossing food than it is about stirring.

Stir fry seems like it would be a great last minute cooking option, but it actually requires a great deal of organization and preparation. What should we keep in mind before we actually start cooking?

Once you start cooking the wok, typically things go really fast. So you really want to have all your ingredients ready — chopping the ingredients properly, marinating or treating the meat, all the sort of steps that you do before you start the actual cooking process. And then the most important part is having what in Western cooking you would call your mise en place, so having all of your ingredients in bowls ready to go. In the recipes. I always list what bowls you should have and what tools you should have around you before you begin cooking.

For example, if you're doing a beef with basil and fish sauce recipe, you would have marinated beef in one bowl, chilies, garlic, shallots, and lime leaves in a second bowl, your sauce mixture in a third bowl, and then you would have your basil in another bowl. You would also have an empty bowl for transferring cooked ingredients as you stir fry them. And then finally, your serving platter.

Once you start cooking, all you have to do is grab the bowl, dump the ingredients in, and follow all the cooking steps without having to worry about running back and forth your cutting board picking things up one at a time. Even more than in Western cooking, I think having those things right by your cooktop before you begin the cooking process is an essential step to a successful stir fry.

Beyond stir fry, what are some cooking techniques and types of dishes that you want people to think about that lets them understand how versatile of a cooking tool it is?

The book is divided up by chapter, and each chapter is a different cooking technique.We cover steaming and simmering, so steaming in a bamboo steamer or simmering in small amounts of water. We cover how to cook rice and rice-based dishes, how to cook noodles and noodle-based dishes, and that includes stir fry noodles, but also sauces that you can make for noodles that you can store in your fridge.

There's also pan frying, so things like dumplings and scallion pancakes, as well as deep frying. Deep frying is the one that might surprise a lot of people. For probably the last 15 years or so, I've been telling people [that] if you have trouble deep frying in a Dutch oven, try deep frying in a wok, because it solves a lot of those problems, including the mess of oil splatter. Being able to maneuver things around a wok is by far the best tool for deep frying.

There's also braising. Because of this flared side of a wok, you're able to reduce sauces very quickly and easily and fit a lot of things in there, more so than in a straight-sided, Western-style Dutch oven or something like that. It really is just a super versatile tool. When people think of a wok, they obviously think of stir fries first, but there's a whole host of other things you can do in it that don't necessarily require the crazy high heat or the rapid-fire technique that you have to practice to get a stir fry down.

Korean Stir-​Fried Shredded Potatoes (Gamjachae Bokkeum)Serves 4 as a small side dishActive Time: 10 minutesTotal Time; 10 minutes

Ingredients

Instructions

*NOTES*

You can easily scale this recipe up by 50 or 100 percent. Increase the cooking time after adding the potato by a minute or two to account for the increased volume. If your tap water is particularly soft (low mineral content), you might find that the potatoes soften or turn mushy during cooking. You can fix this issue by boiling your potatoes in acidic water. Add 2 tablespoons (30 ml) distilled white vinegar to 2 quarts (2 l) water and bring it to a boil in your wok. Add the shredded, rinsed potatoes and cook for 30 to 45 seconds (it’s OK if the water loses its boil during this process), drain, spread on a rimmed baking sheet to steam-​dry, and proceed with the recipe as directed.

Excerpted from “The Wok: Recipes and Techniques” by J. Kenji López-Alt. Copyright © 2022 by J. Kenji López-Alt. Used with permission of the publisher, W. W. Norton & Company, Inc. All rights reserved.

From stir frys to braises, Kenji López-Alt crowns the wok as the most versatile pan in the kitchen. Photo courtesy of Penguin Random House.

You’ve famously done so much food research on both dishes and vessels. In your own home kitchen, do you tend to match vessels to the type of cuisine, or do you use the wok for things like European food as well?

I use my wok more than any other pan. But I also tend to cook a lot of Asian cuisines, whether it's Chinese, Japanese, or Thai, more than Western cuisines. I make pretty much all of my stocks in my wok, whether it's a Western stock or an Asian stock, especially ones where you're going to be browning vegetables or bones before you make the stock. I find it's much easier to just put it in the wok and stir fry them, and then you just pour your liquid in and simmer it.

Sometimes I'll do some braises and things in my wok. The main reason I use it most is because there's such a huge diversity and wealth of different cuisines across Asia. Even just across China, there's a huge diversity in the types of dishes and cooking techniques. Every photograph in this book is the same wok that I've had since I was in college.

Does it matter what kind of rice we use?

It doesn't. tThere are differences in different types of rice, but when you're making fried rice, the best to use is whatever rice you have. So whether that's jasmine, white, or sushi rice, or whatever you have cooked and relatively dry, is going to generally work fine.

When we actually move to the wok with the rice and all our add-ins, does it need to be cooked at a really high temperature?

Generally, yes, you want to preheat your wok to a very high temperature so that your rice doesn't stick to it and doesn't clump up. Whether you're cooking rice, eggs, or even meat, if you don't properly preheat a wok, things are going to stick to it. With rice, you do want to keep things as hot as you can. To that end, I generally recommend cooking in batches. So if you're going to cook a large volume of rice, I would cook part of it first, transfer it out to a tray or a bowl, and then cook the rest of it. And then … you're adding ingredients and toss everything back together at the very end.

Can you describe what wok hei is?

I can describe what I think wok hei is, but if you ask other people, they might give you a very different answer. For me, wok hei was always this thing where when I was a kid, my dad would take us around Chinatown looking for beef chow fun. Whenever we went to a place that he really loved, he would always describe it as having that good smoky flavor. And so, to me, that smoky flavor is what wok hei is.

When I talk to other recipe book writers and other people living in China, for instance, they'll say wok hei is sort of the flavor of a restaurant. It's sitting down outside a restaurant and hearing that sizzle and seeing the steam coming out of the kitchen and drinking a cold beer, and this sort of much more experiential thing as opposed to just that flavor. All these things have to do with using a carbon steel or cast iron wok and having it really hot the entire time you're cooking.