I am Chinese, family from the Canton province, whose cuisine forms the basis of many popular overseas Chinese-inspired dishes, I can explain the “why” on this.
In Cantonese cuisine there is a concept called “锅气” or “wokhei”. It translates to “breath of the wok”. It refers to the distinct flavours and textures that come with an extremely hot flame, because as soon as the food touches the surface of a wok which has been heated to nearly (or past) the smoke point of oil, it cauterises it and causes some interesting chemical reactions. That really means food cooks extremely quickly in that wok and by the time the outside of meat is beginning to overcook, the inside is barely done. That’s also why many Cantonese dishes cooked in this manner have thin-sliced meat and not large slabs, because it would be impossible to have good wokhei and also fully cook the meat.
While it is theoretically possible to get good wokhei on an induction or electric burner, in practice it’s quite difficult to do so because the cooking technique requires smacking the wok around the stove (which would damage induction and electric stoves) and it also requires the entire wok be hot which is difficult to do on induction and electric burners. That’s why they have insane gas burners.
The amount of heat required to sustain the temperature needed for good wokhei is higher than what is commonly possible on home cooking ranges. While typical home methane ranges can output a respectable 5 kW or so of heat output, restaurant-grade wok burners can hit 10-12 kW easily.
Yeah the restaurant burners can hit 30KW (100,000 BTU).
But reminder gas appliances are generously only ~50% efficient, so this performance is matched with a 10-15kW induction wok, which is a hefty electrical load, but doable.
Induction isn’t 100% efficient either.
In any case, 15kw > 60 amps on a 240V circuit. That means you need a 75-80 amp breaker. It’s pretty rare to find that in a residential setting. Even hefty car chargers use a 60 amp breaker.
restaurant burners can hit 30KW
It’s pretty rare to find that in a residential setting
Apple, meet orange.
This explanation is making me hungry :L
Great explanation! Thanks for that. I have tried replicating it, but I don’t want to smash my ceramic stove top. But this really does explain a lot. Perhaps I can still replicate it by putting the heat to an ungodly temperature (well, as high as it will go anyway) and cooking small quantities at a time. Might try it next time I make a wok.
The cheapest way to replicate the type of burners used in restaurants is to buy a standalone outdoor propane wok burner. These may or may not be widely available in your country but in America they can be had for less than a hundred dollars and they put out an ungodly amount of heat.
While they’re still not ideal, I have seen countertop induction burners designed for use with a wok.
I’m not saying that those don’t work, but I haven’t seen any models (even in China) that would survive several hours a day with a Cantonese chef armed with a 2 kg carbon steel wok for more than a week or so.
Yeah no, they might be okay for a home cook who can’t use gas for whatever reason, but I absolutely wouldn’t use it in a commercial kitchen. I mostly mean to say the technology exists, if not yet in a form that makes it competitive with gas.
Thank you for teaching me what “wokhei” means, “cauterized” is a fantastic description of how I like my sear!
I like to cook steak Sous-Vide for that very reason, so I only have to worry about cooking the outermost layer on a screaming hot cast iron.
I’ll have to look more into wokhei to properly apply it it, but this sounds genuinely beyond delicious, thanks again for sharing :)
The workaround is heavy flat pans. Something with the thermal inertia to impart all that energy across a wide surface area, at least long enough to do ingredients separately.
Problem is, woks are usually rounded and deep to allow better temperature control. The closer the food is to the middle, the hotter it gets. That allows chefs to move cooked food to the outside while still cooking any underdone ingredients in the center.
I love that having a shrimp under her hat is now just part of the Chinese chef’s character design 😂
Haha, for real, I remember watching the cooks and seeing those burners… no surprise I can’t fry that rice at home when they are working with a small rocket engine!
Get a cast iron pan. Egg first and hard vegetables first. It won’t be the best but it’ll be good
High heat fried food – sounds carcinogen.
Look, I’m not saying don’t eat healthy… But something has gotta kill you. My friend died in a car wreck a few months ago, just a young healthy dude in the prime of life taken in seconds. Sure, fried food has a cancer risk, so does going outside and playing sports. If I go from eating fried rice, so be it.
To some degree, yes, but if a bit of char gets people to eat more calories from vegetables instead of highly processed foods, the cancer risk is pretty much always offset by decreased diabetes, liver disease, etc.
I’m assuming that the fried rice here has vegetables, of course. I know some people who don’t…
the cancer gives it flavor
Carcinogenoliscious!
Outside in the sun - sounds carcinogen
Yes, WHO says so too.
Stubbing my toe, sounds carcinogenic
If you often do it, so your toe is always inflamed, then yes.
Why?
Char contains a variety of compounds that can be carcinogenic. It’s usually worse with meats than veggies, though veggies still produce at small amount. However, if some char or smoke gets you to eat more otherwise unprocessed vegetables, don’t worry about it; the health benefits pretty much always outweigh the additional risk.
They do make induction models that are curved specifically for woks. Don’t know the right places to search to see if restaurant power level models exist but don’t see any electrical reason it couldn’t be done.
Cantonese person here—electrical equipment is too fragile since Cantonese cooking techniques involve a lot of smacking the wok around.
Some of them have a metal rim that holds the wok just above the ceramic.
That’s just insulating the wok with extra steps
It should be insulated, the more insulated it is the less heat will leak to places other than your food.
Would you also cook food in a frying pan by keeping the pan a few centimetres above the electric burner for the same reason?
I’ll tell you why these two situations are different.
In the case of the electric burner:
- Ceramic top electric burners transfer heat by IR radiation, which leaves the surface of the burner in the shape of a very wide cone. By lifting the frying pan above the burner you are probably creating optical paths by which that IR light can go to places other than the bottom of your pan. Moving away from a heat source like this lowers its intensity not because the energy disappears, but because it spreads out over a greater area. If the stove heated the pan with an IR laser it almost wouldn’t matter how far away it was (there would still be a small amount of loss from air absorption). Potentially you could change the electric burner by adding IR reflectors around the gap between the burner and the pan, but reflection isn’t 100% efficient either, so there would still be some losses compared to just pressing the pan directly against the burner.
- They try to make the glass ceramic material that these stovetops are made of as IR transparent as possible, so that most of the energy ends up in the pan instead of in the ceramic. But they aren’t perfect, and even without a pan sitting on top of them the material will become quite hot. This is relevant because heat flows from hot areas to cold areas, the larger the temperature difference the greater the rate of heat flow. As such, seperating the pan from the ceramic surface in this situation wouldn’t make much of a difference. To be clear its not good that some of the energy goes into the ceramic instead of the pan, but that’s the difference it makes for this comparison.
In the case of induction cooking:
- The induction coils magnetically couple to the pan that sits on top of them. This is a near-field effect, not a radiative one, so things like optical paths and the square cube law do not apply. In fact if you remove a pan from an induction cooktop the energy will have nowhere to go but back into the coils and driver circuit. Most induction cooktops will shut off in this situation because they aren’t designed to be able to reabsorb that energy (the wok ones seem to be a little more tolerant of this though).
- The ceramic is essentially completely transparent to magnetic fields, and isn’t heated by them to any appreciable degree. As such the ceramic surface in an induction cooktop will be relatively cold. Any heating that the surface experiences is a result of pulling heat out of the pan on top of it.
In other words with induction cooking heat appears inside the metal of the cookware without a need for there to be a path by which it can enter. Because of that you can eliminate the paths by which it could exit.
I should say though that the glass ceramics that cooktops are made of are actually pretty good thermal insulators (as evidenced by the fact that, even in an electric cooktop, the entire surface doesn’t get hot, just the area above and right next to the burner). I don’t know if they are better insulators than a centimeter or so of air, but if so then separating the pan from ceramic surface might actually be detrimental, like taking off a blanket when you’re cold. But if this is the case then it would be detrimental for the opposite reason: because you would be reducing the insulation.
With a resistive, electric burner, your point is valid, but we are talking about an inductive range. They don’t work by conducting heat from the range to the pan. They work by inducing an electric current in the pan itself. The heat is produced within the metal of the pan, not within the range. The pan does, indeed, need to be thermally insulated from the range to minimize heat loss.
Mmmmm delicious smacked food. So that’s the secret?
That is actually a very valid reason why it wouldn’t be an in use commercial product at this point.
I’m still fairly sure that can be solved but it is a much higher bar to clear especially to do so and keep it within a cost that isn’t insane.
We get high power electronics in things like rockets and jets and tanks etc. so again I’m sure it is possible eventually. It could easily be a price so high that it doesn’t happen without government mandates or that artificial fuels from bio or carbon capture end up still lower priced than what it takes to make the tougher electronics.
Bonus points if you know the video without clicking the link.
Oh man, I think I get points.
spoiler
Technology connections
Edit: I win!
I assume it’s a technology connections video and that case you’re very right and I’ve already seen it
I’d sell an appendage to have a proper wok burner in my kitchen (appropriate ventilation and fire protection included)
Not sure what your living situation is, but if you have the space for a grill, you can get an outdoor wok stand + propane burner for not a lot of money.
Really high temp is the only thing my induction cooker lacks ability for doing well, but so do most gas cookers I have seen. BBQ can do very high temperatures though, just get a nice big fire going.
Smoking uncle from Guangdong doesn’t even speak chinese.
He makes bomb ass fried rice tho
I don’t think air flows this way around a fire
Is she ashing into her wok???
I don’t think the wok is there yet, otherwise fire would look different.
Ohh, yes, I see. For some reason I thought the ash was provoking a flare up from the wok
