Torch Hei Is the Best Way to Get Wok Hei at Home

Blowtorching vegetables in a wok

[Photographs: Vicky Wasik]

Growing up, I spent my summer breaks visiting relatives in Singapore. Each year, we’d make time for a visit to the famed hawker center in Chinatown Complex—perhaps one of the world’s capitals of masterful wok cooking. One vendor always stood out above the rest: Bald, short and stout, with an impressive mustache reminiscent of the Lorax’s, he’d be slinging char kway teow at breakneck speed. He was armed with nothing more than a handheld propane torch, a wok spatula, and a giant wok balanced precariously on a tiny gas burner. A fine haze of smoke would ripple through the air as he tossed and blowtorched his noodles.

I’ve never seen anyone stir-fry like that since. But sheesh, did his noodles have plenty of wok hei.

People love to geek out over wok hei. In Chinese, it translates to “wok energy” or, more metaphorically and commonly, “breath of the wok.” That elusive, smoky je ne sais quoi emanating from a steaming pile of dry-fried long beans is something many cooks aspire to achieve, but sadly never do. Wok hei is what makes all your tried and true moo goo gai pan worth the delivery fee. And for some people like my dad (who grew up in China), when it comes to stir-fries, “If it doesn’t have wok hei, it isn’t Chinese food.”

Serious Eats has covered this ground before. Kenji has championed the grill-wok method for years. He’s even waxed poetic about the mythical WokMon, a metal ring that can transform a burner on your stove into a concentrated jet afterburner ideally suited for the job. Both methods clearly have their advantages. But I consider myself a man of the people, and I see two issues from the jump.

First, let’s face it: Who in their right mind is going to fire up a grill just to whip up some beef and broccoli on the fly? That seems to me to get away from the spirit of stir-frying in the first place, where speed and efficiency are the name of the game. In the dead of winter—particularly in a city like New York, where outdoor space is a pipe dream and owning a grill is a rare luxury—the grill-wok method doesn’t seem like such a sweet idea.

Second: Many people don’t own gas ranges. For many apartment-dwellers, electric stoves are increasingly the norm. Chalk that up to your building code, or the fact that your landlord has zero faith in your ability to keep a medium-low flame. Suffice it to say, if you’re in the no-gas camp, the WokMon isn’t a viable option, either.

So how else can you get close to producing wok hei? Is it even possible?

Flame On: How Wok Hei Works

GIF showing process of tossing ingredients in wok while using the flame of a kitchen blowtorch to achieve wok hei.

According to Kenji, wok hei is a complex flavor that comes “from a combination of polymers and oil breaking down within the skillet, and from microscopic droplets of fat vaporizing as you toss food up and over the edge of a wok into the hot column of air created by the intense burner below.” Great. Screaming hot seasoned skillet? Easy enough—at least in the beginning stages. Like Kenji says, there will be significant heat loss as soon as you add food to the pan. A Western skillet does an average job of regaining heat over time, but a flat-bottomed wok tends to fare better, even on your garden-variety, pitiful-BTU Maytag burner.

So, we don’t have the benefit of high heat output if we’re cooking indoors. But let’s unpack that last part about vaporizing fat in hot air. A portion of wok hei is derived from the thermal decomposition or combustion of oil that’s on the food or in the seasoned wok. (There’s also a cascade of flavors coming from caramelization of sugars and various Maillard reactions.) In cook’s terms, controlled flare ups could generate some of the smoky, singed flavor we’re after.

That means we want to engineer the right conditions for flare-ups, and that means starting with moisture. Specifically, as water in stir-fry ingredients boils out and evaporates during cooking, vigorous stirring or tossing causes oil in the pan to mix with water vapor, producing a cloud of fine oil droplets. Those droplets can ignite if they come into contact with, say, a screaming hot column of air, or, even, a direct flame. The result is the thermal decomposition of oil, i.e. one part of wok hei.

Hacking Wok Hei at Home: The Blowtorch

two blowtorch options for torch hei

Enter Mr. Lorax from the hawker stall. Could a blowtorch be the answer?

I knew I could definitely get some flare ups going with a blowtorch. Many home cooks use them—if only to flambé bananas as a party trick or to finish off that crème brûlée they make once every three years. But blowtorches have plenty of utility in the kitchen beyond the occasional culinary gimmick: You can easily melt the cheese on your nachos—or on anything, for that matter; you can quickly get some color on sous vide steaks and other meats; or you can use a torch to pop those pesky bubbles on the surface of custardy desserts like panna cotta. Still, would using a blowtorch translate to any appreciable increase in flavor? I decided to put it to the test.

Test 1: Vegetables

I started with the simplest stir fry I could think of: yu choy. Yu choy is a dark and leafy green, prevalent in Chinese cooking. It also has plenty of water content and cooks in a flash, making it an ideal benchmark ingredient for my tests.

First, I cooked the greens in nothing but vegetable oil in a ripping hot seasoned carbon steel skillet. Initially I didn’t have a flat-bottomed wok on hand to test this idea out, but I figured it was best to start from the lowest common denominator (because if it worked with a skillet, it would definitely work with a wok). I kept my cooking time to 60 seconds and seasoned with a measured amount of salt.

In the next batch, I kept everything the same. But in the last 20 seconds, I held a blowtorch over the skillet, hovering the flame two inches from the greens as I stirred vigorously. With a heavy-bottomed skillet, this turned out to be pretty easy. I could stir comfortably with one hand and torch it up with the other.* As expected, this action created a series of small flare-ups. Nothing crazy, but enough to get some real combustion going.

* With a wok, I adjusted my stirring to a gentler scoop-and-push motion—decidedly more “spirited” than vigorous. As I got even more comfortable with flipping food in the pan, I ditched the spatula altogether, which actually made the process feel more intuitive.

The difference was immediately apparent. Sure, the plain stir-fried yu choy were respectable sautéed greens that tasted clean, salty, and vegetal. But on the other hand, the torched yu choy were transformed. At first whiff, I could detect those tell-tale aromas of a legit stir fry: the greens were smoky, singed, faintly charred in all the right ways. Overall, I thought I’d achieved a worthy approximation of wok hei.

Stir-fried yu choy

I proceeded to run through my entire fridge, testing the waters. Mushrooms? Amazing. Baby bok choy? You bet. Celery was a win, and cucumbers were a particular revelation. But there were some exceptions: Vegetables with an appreciable sugar content, like onions, tended to burn when exposed to an open flame. Others with relatively lower moisture content, like carrots and broccoli, did not flare up as easily, and didn’t take on as much of that smoky intensity.

The verdict: A blowtorch works great on vegetables with relatively higher moisture content and relatively lower sugar content.

Test 2: Meat

What about meat? I tried several batches of lightly marinated chicken, beef, even fish. They worked reasonably well, but the wok hei was less pronounced than for higher-moisture vegetables. I wasn’t seeing a ton of flare-up action initially, especially at those crucial final stages of cooking. Adding a splash of water to the marinades—and even directly to the pan toward the end of cooking—seemed to improve things. I suspect that the added moisture helped produce more of that fine mist of oil droplets essential to combustion.

The verdict: Marinate your meat with extra water to get good torch hei flavor.

Test 3: Fried Rice

Fried rice was tricky. By the time I developed enough wok hei, the grains invariably burned slightly. White rice was a particularly fickle mistress. The rice became distinctly smoky, but not without some visible char, which could be undesirable for some. The solution? Stir-frying and torching vegetables separately before incorporating the rice. This step ensured just enough wok hei in the finished dish, without risking charred grains.

The verdict: Torch your vegetables separately to avoid burning your grains of rice.

Test 4: Stovetop Ranges

Of course, this technique would be far less useful if it only worked on gas burners. Not one to back down from a challenge, I called up my friend to see if I could cook some bok choy on his ancient electric coil stovetop. His was a particular abomination, mottled with rust and with sections of coils that didn’t even heat up anymore. But despite it taking just about the whole evening to heat up the pan, the process and results were similar. (I managed to set off his smoke detector—much to the chagrin of his partner—so I don’t think I’ll be invited back anytime soon.)

The verdict: It’s not as quick and convenient, but this technique also works on electric burners.

Test 5: Cooking Vessels

Do you need a real wok to create torch hei? The short answer is no; this method works with either a skillet or a wok. But, as Kenji notes, using a seasoned pan is key—those hard-earned layers of polymerized fat do make a difference in flavor**.

** Learn more about how to buy, season, and care for a wok here, how to buy, season, and care for carbon steel skillets here, and how to buy, season cast iron skillets here.

I found that heat control was a little trickier with a Western carbon steel skillet, and that vegetables were browning a bit faster than in a wok by the time I got to torching. The wok has several benefits over a carbon steel skillet: the differing temperature zones—the screaming hot bottom, the cooler sides; more rapid heat gain; more space to stir; and, finally, cooking with a wok feels way cooler.

Verdict: Seek out a seasoned carbon-steel flat-bottomed wok or slope-sided skillet. If you don’t have either, a cast iron skillet will work in a pinch.

The Way of the Torch

Blowtorching vegetables in a wok

For best results, I found that blowtorches with an on-off switch or dial were easiest to use. I happened to have a massive propane canister with a BernzOmatic TS4000 trigger-start torch head—the Rolls-Royce of torch setups. Did I need a blowtorch rated for welding? Probably not, but if you already have one on hand, it’ll do the trick. I also had good results with much smaller, cheaper handheld models like the Iwatani butane torch and this cute little blowtorch from Jo Chef.

When handling a blowtorch, the most important thing is to control your flame. You don’t need to channel your inner Khaleesi and rain merciless dragon fire upon your poor, unsuspecting bok choy. In fact, a big, bright orange or yellow flame isn’t necessarily a good thing when it comes to generating wok hei. First, there’s the matter of color. When it comes to propane and butane torches, a blue flame is best. Blue indicates complete combustion of fuel. An orange or yellow flame indicates incomplete combustion, where fuel is left unburned. This extra carbon will cause soot to form, which shows yellow or orange incandescence in a flame. Soot is what you taste when a cook recklessly torches your sous-vide steak, producing an off-putting lighter-fluid aroma. A blue flame also burns hotter, on the order of 1980-2000°C; an orange or yellow flame burns considerably cooler, around 1000°C.

Range of blowtorch flames, from blue to orange.

Second, there’s flame size, which roughly correlates to how much fuel you’re letting out of the canister. Combustion requires both oxygen and fuel. For air-only blowtorches like the ones I used, oxygen comes from the surrounding air through small intakes in the burner tube***, and only at a certain rate. If you open the valve all the way, you’ll get a big flame, but you’ll also probably see an orange or yellow flame. That’s because fuel is being released from the canister at a rate faster than oxygen from the air can be taken in, resulting in imperfect combustion and sooty-tasting food.

***This comes from the Venturi effect, which creates a pressure differential that causes air to enter the stream of gas through little holes or inlets

All that science boils down to this: Keep your flame small, concentrated, and blue.

But what about that crazy yellow flame in the action shots?

I know, I lied to you. You can clearly see a jet of yellow fire in the pictures. Doesn’t yellow mean soot, and doesn’t soot mean foul flavor? Not in this case. That yellow flame you’re seeing is most likely the combustion of oil vapor—unrelated to the combustion of propane or butane fuel from your blowtorch. If you’ve ever seen a grease fire (I pray that you haven’t) or left oil heating in a skillet so long that it self-ignites (again, not worth trying), you will have seen it burn yellow to orange. (Please, for the love of your safety and your eyebrows, don’t actually try recreating these things. That’s what the internet is built for.) Also remember: the combustion of oil produces singed, smoky, slightly grill-like flavors—definitely not sooty.

Rules and Guidelines: How to Get Torch Hei at Home

Taking all my trials and moderate, albeit calculated, pyromania into account, here are some guidelines for producing successful torch hei. If you follow all of these rules closely, you can have your wok hei, and you can do it safely. At the end of the day, you’re cooking with a blowtorch here. Know the risks involved, and
be a responsible cook.

1. Stay Safe

Whether you’re using a wok or skillet, keep your cooking area well ventilated. Open a window (or three), disable your smoke detector, and break out a fan if you can. I won’t sugar coat it: Things will get hot and smoky—even if you don’t use a torch—but you’ll only be cooking for a few minutes. So be prepared.

And while we’re on the subject of general kitchen safety, invest in a small fire extinguisher. Even if you never try this technique, having a fire extinguisher handy is still always a good idea when cooking. If you are trying the technique, at the very least, keep a lid nearby. You can easily snuff out most fires by covering the pan and depriving the flames of oxygen. And whatever you do, never, ever use water to put out a kitchen fire, unless you want to have a Michael Bay-level inferno on your hands.

Here’s a more complete list of fire-safety tips.

2. Prep Wisely

Closeup side view of stir-fried cucumbers with trumpet mushrooms.

For this technique, moisture content is key. High-moisture vegetables take best to this technique, followed by meats, and to a lesser extent rice and grains. Cut everything to the same relative size, so that cooking times are short and roughly equivalent.

3. Cook in Batches

Don’t crowd the pan. You’ll never get close to wok hei if there’s too much food in the pan. If you find it difficult to stir food around without spilling, you’ve crowded the pan. If the pan is cooling down way too much to the point that you see steam, you’ve crowded the pan. There’s no shame in cooking in batches, especially when the payoff is proper wok hei. Plus, you’ll need that extra space to toss your food around while you’re torching away.

4. Torch in Moderation

This is what too close looks like.

You don’t need as much torch action as you might think—and it’s generally best to introduce the torch in the later stages of cooking an ingredient. You only need 20 to 30 seconds of controlled flame action to get good results. If bok choy takes two minutes to cook, save your torch for that last minute. That way, you also avoid producing unwieldy flare-ups in the beginning stages due to excess water from washing and cleaning your produce.

While we’re at it, be sure to hold the flame above the food, not on it. Remember, the goal is to combust some oil in a controlled manner. Holding the flame at least two inches away from your food is ideal. Don’t hold the torch so the flame is right on the food—you’re not looking to carbonize your stir-fry. Any time you hold the torch too close to the food, things end up tasting like soot and uncombusted fuel. I also found that there was a sweet spot right at the topmost edge (at the 12 o’clock position) where the sidewall meets the bottom of the pan.

5. Go Easy on the Sauce

Overhead of four dishes made using the torch hei technique: stir-fried cucumbers with mushrooms, fried rice with Chinese sausage and cabbage, stir-fried bok choi, and yu choi.

No matter how much flavor you develop using a blowtorch, you’ll never taste it if it’s drowning in an intense fermented black bean concoction or a cup’s worth of oyster sauce. This technique is subtle, and the flavors produced deserve your respect. Let the technique shine, and you’ll be blessed with some tasty, aromatic food.

Which brings me to the last and most important point…

This is not a substitute for the real deal. The flavors produced via blowtorch resemble wok hei, but they are by no means the real thing. I’ll still gladly order kung pao chicken from my local establishment, because there’s no substitute for actual wok hei. But if you want a quick hit of wok flavor on the fly, this technique is worth the effort—and it’s pretty fun.

Ttry out these recipes the next time you’re hankering for some stir-fry. They’re great examples of the method in action, and they’ll give a good idea of how to incorporate a torch into your Chinese cooking.

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