The Food Lab

Unraveling the mysteries of home cooking through science.

The Food Lab: The Best Korean Fried Chicken

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[Photographs: J. Kenji Lopez-Alt]

You could say we have a thing for fried chicken in our household. My wife recently ran in her first 5k race (and came in 8th in her class!). The only thing she asked me for to celebrate with? Not Champagne, not a night on the town, not even a complaint-free girly-movie night. All she wanted was fried chicken.

The thing is, we don't eat it that often round these parts. A few times a year, max. So when we do get around to it, it had darned well better be the best fried chicken out there.

And when it comes to frying chicken nobody—and I mean nobody—does it better than the Koreans. My apologies to all you Southerners.

Korean fried chicken (or KFC as those in the know call it) differs vastly from American-style fried chicken. Rather than the craggly, crusty, significant coating you'd get on say, a Chick-Fil-A sandwich or a Popeye's drumstick, you get an eggshell-thin, ultra-crisp crust around a drippingly juicy interior.

The end goal is clear, but the road to get there required a bit of bushwhacking.

The Chicken

First things first: the chicken. In Korea and in some of the Korean joints around here in New York, I've had fried chicken made with both light and dark meat. But we all know which one is superior, right? Dark meat can withstand the high temperatures of frying and have a much greater window of time between being perfectly cooked and overcooked.

With white meat, on the other hand, even a few degrees above the right temperature—an extra 15 to 30 seconds in the oil—and you end up with dry string meat. In Korea, they mitigate this by using very very small, young birds that have a higher concentration of moist connective tissue in their breast meat—the equivalent of using a Cornish hen. And while frying Cornish hens is one very easy way to guarantee moist breast meat, here's an even easier, tastier way: just use wings.

Tastier and cheaper with a better ratio of skin-to-meat (that is, more skin, less meat), they're a natural choice. I like to use meaty whole-wing portions with the tips still attached rather than dumettes and flats.

Sticky Situation

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Where has all my batter gone?

I started my testing with a very basic thin batter of flour and water into which I dipped my chicken wings before frying in hot oil. (Peanut oil or shortening are my frying media of choice for optimum crispness and re-usability).

Korean fried chicken typically uses a thin, thin batter that barely coats the wing in order to get that eggshell-thin crack. My first task was to figure out a way to get that batter to stick. Chicken wings are covered in fatty skin that is a natural repellent for water-based liquids. Try dripping a wing straight out of the package into a batter, and you'll find that it just runs straight off. Just like a painter rolling on a layer of primer to make sure the paint sticks to the walls, my chicken wings needed some kind of pre-treatment.

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I tried a variety of tactics including air-drying overnight (successful but time consuming), salting to carefully draw out moisture then drying (works!), coating with a salt and baking powder mixture (also works! The baking powder raises the pH of the surface, allowing it to crisp better*), and tossing in plain cornstach to absorb some surface moisture and create a rougher texture for the batter to adhere to.

*See more on the science of baking powder and chicken wings in this article on oven-fried buffalo wings.

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The best was actually a combination of all four methods: I tossed the chicken wings in a mixture of corn starch, kosher salt, and baking powder, before spreading them out no a rack and letting them air-dry for about an hour (overnight is better, but even as little as fifteen minutes will work).

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Once the coating was in place, I had no trouble getting my batter to stick. But which batter is best?

No. 2: The Starch

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The goal of frying a batter is twofold. First, hot oil causes moisture and air inside the batter to evaporate, leaving you with a dried out crust in place of a wet slurry. Simultaneously, protein networks within the batter will harden, making your batter stiff and crisp. While all this is going on, you're also browning both proteins and carbohydrates, creating new flavorful compounds. So frying is about drying, hardening, and browning.

Where does the recipe for batter fit into this? Well, working with batter is a balancing act between crispness and structure. See, when you mix flour with water, two proteins called gliadin and glutenin start to bond with each other, eventually forming a stretchy, net-like matrix of intertwined proteins called gluten. It's the same protein network that gives good bread its structure or allows pancake batter to hold onto its airy bubbles, and it's this network that hardens when you fry.

Some gluten development is necessary—it provides structure and support. But too much gluten development can lead to tough or leathery crusts.

Take a look at these two wings, one made with a pure water and flour batter, the other made with a corn starch and water batter. Corn starch is a pure starch, meaning that its protein content is essentially zero, and it produces no gluten when combined with water.

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Using 100% flour gives you a thing that is leathery and greasy—too much gluten forms, making the coating too robust. On the other hand, 100% corn starch produces a coating that is powdery with relatively little browning (the proteins in flour aid with browning). To get a crust that's both robust and crisp, you need to use a combo.

I fiddled around with the ratios and found that a 50/50 mix of all-purpose flour and corn starch was as good as I could get it. But I was still unhappy with the results. For starters, everything could have browned a bit better. And more importantly, no matter how hard I tried, no matter how many flour/corn starch batter I used, no matter how many cooking temperatures or different fats I tested, there seemed to be a limit to how crisp I could get the coating. Heck, I even tried using no batter, just tossing the dry starch-coated wings directly into the fryer. No dice.

There had to be something more to the technique.

Powdering Up

In a classic fried chicken or any other batter-based recipe, how do you make the batter crisper and lighter? One trick is to use a leavener like baking powder. This accomplishes two goals. First, it raises the pH of the batter, which has the effect of increasing its browning properties.

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Secondly, and more importantly, it creates tiny, tiny air pockets that bubble up as the batter hits the hot oil. These pockets not only increase the surface area of the batter, making it crisper and crunchier, but they also break up the thick layer of batter, reducing its toughness.

Ok, so then why not just increase the amount of baking powder in a recipe until the batter is as crisp and as light as you want it?

Here's what happens:

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With too much baking powder, the bubbling gets out of control. Rather than forming crisp bubbles and layers, when an over-baking-powdered batter hits hot oil, it erupts violently, popping bubbles and blowing them off of the wings. The goal is to inflate those bubbles to maximum capacity without causing them to rupture, not to make them burst. When that happens, grease rushes into the cavities where the bubbles used to be. You end up with an inedibly oily wing.

1/2 teaspoon of baking powder per cup of flour/corn starch mix was about as high as I could go.

My next thought: what about double-frying as some recipes suggest?

I tried it repeatedly, and found that I never really got anything that was markedly superior to a single-fry. Double frying works in some cases—when building up the gelatinized starch layer in a perfect french fry, for example, or when softening naked chicken skin to get ready for bubbly expansion in a confit-style double-fried buffalo wing. It's even a great method for an ultra-crunchy craggy batter in traditional Southern fried chicken.

But with a thin batter-based fried food? It doesn't really make much difference, other than allowing you to rapidly re-heat and serve large portions of par-cooked chicken; I suspect that's where the idea for the technique originated from; It's something that's useful in a high volume restaurant, but unnecessary for a home cook.

Thinking Thin

Here's the problem: I had two conflicting goals here. On the one hand, I want to get my coating as thin as possible. Eggshell thin with a crunch to match, remember? This meant that unless I was willing to manually paint a thin layer onto each wing pre-frying with a paint brush ( a prospect I didn't completely disqualify), then making a thinner batter by adding more liquid was the only recourse.

Unfortunately, adding more liquid to a batter has an unfortunate side-effect: It actually makes the batter tougher. Weird, right? You'd think thinner batter = thinner coating = crisper crust. However, what you find is that as you thin a batter out, the final fried product goes from having a too-thick, too-crunchy crust when the batter is thick, to a thin-but-leathery-and-not-crisp crust when the batter is too thin.

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The culprit, once again, is gluten formation. The more water you add to a dough or batter, the more easily those flour proteins swish around and bind with each other, thus the more easily gluten forms. What I needed was a way to thin my batter while simultaneously limiting gluten formation.

My first thought was to make a very thin slurry with just corn starch to coat the chicken, then dip it into a dry corn starch/flour mixture to add a bit of heft and extra brownability to it (as we've seen, a plain corn starch slurry doesn't work so well)

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No dice. It came out crisp alright, but the coating was unpalatably thick and tough (the wing on the left in the photo above).

The solution had to be built into the batter itself, and it just happens to come in a bottle.

Booze Clues

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Regulars at Lenox Liquors on 133rd and Lenox will recognize Georgi as the cheapest vodka they offer (1.19¢ per milliliter!), while fans of Heston Blumenthal will recognize vodka as one of the ingredients in his Perfect Fish & Chips recipe. If you are in the small group of people who recognize both this bottle and its context, then we are kindred spirits and I welcome you to my home for fried fish any day of the year.

*It's a brilliant recipe that you should all check out, by the way. You can catch the video here.

When Heston presented the idea, initially the thought was that the volatility of the vodka (that is, its propensity to evaporate quickly) would cause it to jump out of the batter faster as it fries, allowing the batter to dehydrate quicker and thus brown faster and crisp up better in the same amount of time. At that task, it serves admirably.

But for my purposes, there's an even more important factor it brings to the table: Limiting gluten development.

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Back when I was working at Cook's Illustrated in 2007, I came up with a recipe for Foolproof Pie Dough that relied on the same principal to achieve the same goals: better hydration in dough/batter while simultaneously limiting gluten development. The idea is that since 80-proof vodka is 40% alcohol and gluten does not form in alcohol, you can add more vodka to a batter than you would be able to water, while maintaining the same (or even a diminished) level of gluten formation.

Precisely what I'm looking for with my fried chicken.

Take a look at the photo above, made with a thin batter of flour, corn starch, and a touch of baking powder mixed with water. Notice that while the coating brown, it appears a little papery. (Ok, tough to show that texture in a picture, but take my word for it—the batter was flexible, and a little tough, despite being very thin). Then take a look at this picture:

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Exact same batter, exact same proportions, totally different results. There are some clear advantages offered by the vodka. First off, its volatility means more violent evaporation, which means a more blistered, bubbly appearance and more surface area, leading to extra crunch. More importantly, it means limited gluten formation. This means a thin, thin crust that gets extra-extra crisp. And wait, there's more!

With most batters, you've got to use them very soon after they are made. Even as they sit, gluten develops—any fry cook will tell you that the first piece of fish or the first onion ring to come out of a particular batch of batter is the best one. As time goes on and gluten develops, they get progressively breadier and breadier. At really great Japanese tempura shops, every batch of batter will be made fresh to order, to ensure maximum lightness.

With a vodka-based batter, the useful shelf-life of a pre-mixed batter is drastically extended. You can mix this batter, go catch an episode of Good Eats on youtube, walk the dogs, and start on your income tax return and it'll still produce thin, perfectly crisp chicken wings.

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Bam. That's what I'm talking about.

To be quite honest, the wings were so damned good on their own that they didn't even need a sauce—this mirrored the thoughts of some of the restaurants that served great naked wings in Korea. But I guess the dress is what makes the prom queen, so I went ahead and developed a couple anyway.

A sweet soy-based sauce flavored with garlic and ginger along with a spicier gochujang-based version are the traditional choices, but if you want to make my wife really happy, skip'em both in favor of Buffalo wing sauce.

That's the kind of fusion I can really get behind.

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About the author: J. Kenji Lopez-Alt is the Chief Creative Officer of Serious Eats where he likes to explore the science of home cooking in his weekly column The Food Lab. You can follow him at @thefoodlab on Twitter, or at The Food Lab on Facebook.

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