Wok Hei, High Heat, and Oil: What's the Relationship?

[Chris Amirault]

Yesterday I was watching someone stir-frying in a well-seasoned wok. They put the wok over high heat, poured in oil, and intentionally ignited it. Immediately after the aromatics went in the flames died.

It made me wonder about the relationship between wok hei, high heat, and smoke/flame points of oil. I mean, I never try to ignite the oil when I'm about to stir fry in a wok. What gives?

[mbhank]

Get "The Breath of a Wok" by Grace Young. Great cookbook with explanation of Wok Hai. I suspect that you may have been watching a professional chef at work. Do not try this at home!

[Chris Amirault]

Got Breath of the Wok but I don't remember seeing anything about that subject. In addition, I have an outdoor wok burner, and so I could do this if it were a recommended practice. But is it? Or not?

[Ben Hong]

Chris, there are some cooks out there who think that the flash adds something to the dish. I think that it's a case of bullsh!t baffling brains or just for show. Flames at that particular stage of the cooking process does not add anything to a dish. But then I have been wrong once before.

Seriously, the commercial wok burners are always on "afterburners" hot with flames licking around the wok and the merest spritz of oil will ignite. Not intentional, just an accepted part of the process.

[Chris Amirault]

Thanks, Ben, that makes a lot of sense. The TV cameras were rolling after all....

[hzrt8w]

Got Breath of the Wok but I don't remember seeing anything about that subject. In addition, I have an outdoor wok burner, and so I could do this if it were a recommended practice. But is it? Or not?

Try it! I do taste the difference. You can try it with the flame and another time without and taste it for yourself.

Induce the flame by heating the wok over high heat, with oil, with your aromatics like garlic and ginger and other sauces. Dash in some Shaoshing wine and tilt the wok and lead the wine trail to the burner's flame. Viola! Flame ON! (Your hair got burnt... )

My speculation is that the flame caramelizes (maybe so slightly) the ingredients, which leads to "wok hei". (And the coating of your wok from years of caramelization adds to the flavor.)

[jsager01]

Try it! I do taste the difference. You can try it with the flame and another time without and taste it for yourself.

Induce the flame by heating the wok over high heat, with oil, with your aromatics like garlic and ginger and other sauces. Dash in some Shaoshing wine and tilt the wok and lead the wine trail to the burner's flame. Viola! Flame ON! (Your hair got burnt... )

My speculation is that the flame caramelizes (maybe so slightly) the ingredients, which leads to "wok hei". (And the coating of your wok from years of caramelization adds to the flavor.)

yes, there is a definite difference. I guess the reason why some have doubts about 'wok hei' could be because they have not identified or associated that special 'flavor' as 'wok hei'?

For example, i have heard many others say that " i can never replicate the flavor of chinese restaurant dishes, especially cantonese stir fries". Of course, there could be many reasons for this, but my standard reply is "try getting a standalone gas burner, keep it in the backyard or garage, and turn it up as high as you can".

If i understand correctly, Chris in his first posting, saw someone flaming a wok with oil before adding the aromatics. I dont do it this way, but do as described by 'hzrt8w' in his posting above.

[Chris Amirault]

I haven't had a chance to try this yet -- it's still lousy weather here and I can't flame oil in the house -- but to jsager01's point, I think that most people don't actually have seasoned woks, either. High heat is important, but a seasoned walk is critical to wok hei.

[Ben Hong]

I am of the opinion that you don't need shooting flames to achieve wok hei. In our family restaurant some 50 years ago we had the standard stainless steel wok burners (a bank of 5) with 24 and 30 inch woks. If you recall, most of the showy flame flashing cooking shown on TV was done with small 16-18 inch woks that allows the cook to pick up and flip the wok and food around, allowing the flames to shoot out of the burner (insert oooohs an ahhhhs here). Now the head cook in our kitchen was my very senior septagenarian uncle who was about 5 ft. zip tall and weighs in at 110 lbs with anchors in his pockets. You think that he could pick up a 24" wok laden with food and flip it around all day just to show some flames??? This is the same illiterate guy who used to cook on the Canadian railroads being built in the early 20th century, the same guy who committed nearly 1000 recipes to memory... Chinese, western, and desserts.

Wok hei?? I think he was on the committee that coined the phrase . He didn't need no steenkin' flames to get wok hei!!!

[dmreed]

Got Breath of the Wok but I don't remember seeing anything about that subject. In addition, I have an outdoor wok burner, and so I could do this if it were a recommended practice. But is it? Or not?

"wok hay" essentially means "breath of the wok"!

I have never seen a Chinese chef light the oil on fire...I suspect that the chef you saw did not intentionally light the oil fumes on fire but that the fumes and spatter from the extremely hot wok simply drifted down and ignited...this even sometimes happens when cooking a steak in a skillet!

[Chris Amirault]

The chef most certainly lit the oil on fire intentionally. The question is whether it was merely flair, or whether it has any culinary purpose. Increasingly I suspect the latter.

[dmreed]

did the chef actually use some device to ignite the oil or did he/she tilt the wok to allow ignition?

what I have observed with Chinese chefs is a brief flair up when the wok is shaken after some liquid is first added...the liquid caused the hot oil to spatter and then the oil ignites briefly.

I am under the impression that the extremely hot wok/oil (basically impossible on an ordinary stove top) slightly chars the ingredients which produces the wok hay...at least, that is what I taste and smell.

I agree with the previous post stating that slight carmelization probably occurs but I doubt it is enough to taste/smell.

IMHO trying to ignite the oil inside at home would be very dangerous unless the stove hood and cooking area are designed for such a practice. the flash point of oils vary but if vaporized oil accumulates in the cooking area, the room could actually explode! properly equipped professional kitchens have powerful venting systems to prevent such occurances.

even outside could be dangerous, remember all the warnings regarding deep frying a turkey outside and the possibility of spattering oil causing a fire!

Edited March 15, 2010 by dmreed (log)

[Chris Amirault]

Yes, the chef tilted the wok so that it ignited the oil.

[dmreed]

a definite tilt or a shaking of the ingredients?

before or after adding some liquid?

just curious, this is very interesting to me.

[CFT]

I don't see the need to "flame on" for wok hei. Wok hei is purely about high temperatures and the spatial eveness of the temperature, helped by the shape of the wok, so that all the food is cooked evenly at the same time. So heat source, wok construction (thermal conductance) and choice of cooking oil should be prime considerations in achieving wok hei.

You don't make caramel by burning the sugar!

[Chris Amirault]

a definite tilt or a shaking of the ingredients?

before or after adding some liquid?

Empty, hot wok.

Oil.

Tilt and flame.

Aromatics.

Flame goes out.

[jsager01]

Let us try to identify and share our experiences with the parameters/necessary conditions to achieve wok hei? assuming that we are agreed that there is such a thing as wok hei; something akin to how umami came to be identified/recognised/legitimised?

what i have found as 'necessary conditions', most of which have already been identified by posters on this thread, are:

1. a well seasoned wok to start with

2. high temperature and the 'spatial eveness of the temperature' (i like this, perhsps the author may want to take out a patent for this?), heat source, and choice of oil (but no olive oil, please). To achieve this indoors in a home environment, i find that it helps to cook smaller portions at the highest heat possible, in fact, try cooking one serving at a time. Its a pain, but the rewards are worth it.

3. In the chinese restaurants that i have been previleged to observe, whenever they cook something for which wok hei is critical, it is always customised, ie one stir fry for each customer, ie no mass cooking as you would expect for a buffet, stew, etc, ie no big wok cooking massive portions.

4. yes, 'flame on' is not necessary to achieve wok hei, but if i can get a 'flame on' by tilting, by 'accident', or whatever meams, it is feedback that i have achieved wok hei, and for me that is a good thing, ie i am not that good/confident a cook that i know that i have wok hei without the flame on. Put it in another way, if i have not achieved wok hei, i can never get a flame on no matter what/how i try.

[dmreed]

Let us try to identify and share our experiences with the parameters/necessary conditions to achieve wok hei? assuming that we are agreed that there is such a thing as wok hei; something akin to how umami came to be identified/recognised/legitimised?

DMREED: AKIN? HOW? UMAMI WAS RECOGNIZED AS A TASTE BEFORE IT THE CHEMICAL CAUSE WAS ISOLATED. CAN YOU BOTTLE WOK HAY? IF SO, I WILL TAKE A CASE! I STILL THINK WOK HAY IS THE RESULT OF SLIGHT CHARING OF THE FOOD IN A VERY HOT WOK BUT LIQUID SMOKE IS NOT A VIABLE SUBSTITUTE....HUMMMM, MAYBE IT IS IN VERY SMALL QUANTITIES, HAS ANYONE TRIED IT?

what i have found as 'necessary conditions', most of which have already been identified by posters on this thread, are:

1. a well seasoned wok to start with

DMREED: ABSOLUTELY!!!

2. high temperature and the 'spatial eveness of the temperature' (i like this, perhsps the author may want to take out a patent for this?),

DMREED: EVENNESS OF TEMPERATURE? THE SIDES OF THE WOK ARE SUPPOSED TO BE LESS HOT THAN THE BOTTOM SO FOOD CAN BE PUSHED UP OUT OF THE EXTREME BOTTOM HEAT

heat source, and choice of oil (but no olive oil, please). To achieve this indoors in a home environment, i find that it helps to cook smaller portions at the highest heat possible, in fact, try cooking one serving at a time. Its a pain, but the rewards are worth it.

DMREED: AGREED, SMALL QUANTITIES WILL DEFINITELY HELP. LARD WAS TRADITIONAL AND VERY TASTY BUT VEGETABLE OILS ARE NOW POPULAR.

3. In the chinese restaurants that i have been previleged to observe, whenever they cook something for which wok hei is critical, it is always customised, ie one stir fry for each customer, ie no mass cooking as you would expect for a buffet, stew, etc, ie no big wok cooking massive portions.

DMREED: USUALLY FOR A GROUP, A COMMON DISH IS PLACED ON THE TABLE FROM WHICH EVERYONE SERVES THEMSELVES...EVEN THE SOUP. RICE IS THE EXCEPTION. HOW WOULD EACH PERSON BE SERVED SEPARATELY UNLESS THEY ORDERED IT BY THEMSELVES SUCH AS A LUNCH COMBO?

4. yes, 'flame on' is not necessary to achieve wok hei, but if i can get a 'flame on' by tilting, by 'accident', or whatever meams, it is feedback that i have achieved wok hei, and for me that is a good thing, ie i am not that good/confident a cook that i know that i have wok hei without the flame on. Put it in another way, if i have not achieved wok hei, i can never get a flame on no matter what/how i try.

DMREED: ACTUALLY IT IS QUITE EASY TO GET FLAMES...BOOKS ARE FILLED WITH INSTRUCTIONS ABOUT HOW TO PUT OUT STOVE TOP FIRES...I WOULD AGREE THAT IF THE WOK IS HOT ENOUGH TO CAUSE THE SPATTERING WHICH LEADS TO FLAMING THEN THE WOK IS HOT ENOUGH TO ACHIEVE WOK HAY BUT, DEPENDING ON THE HEAT SOURCE AND THE WOK ITSELF, THE HEAT MIGHT BE DECREASED TOO QUICKLY TO ACHIEVE WOK HAY..AGAIN SMALL PORTIONS WOULD HELP WITH THIS PROBLEM.

[hzrt8w]

.....

what I have observed with Chinese chefs is a brief flair up when the wok is shaken after some liquid is first added...the liquid caused the hot oil to spatter and then the oil ignites briefly.

.....

The liquid that you spoke of is Chinese cooking wine, I believe. Alcohol.

Oil droplets + alcohol + high heat = flame.

You don't really need to use a lighter to deliberately "light the wok on fire". The oil/alcohol fume over high heat, just tilting the wok slightly it will "catch" the flame.

Edited March 16, 2010 by hzrt8w (log)

[dmreed]

.....

what I have observed with Chinese chefs is a brief flair up when the wok is shaken after some liquid is first added...the liquid caused the hot oil to spatter and then the oil ignites briefly.

.....

The liquid that you spoke of is Chinese cooking wine, I believe. Alcohol.

Oil droplets + alcohol + high heat = flame.

You don't really need to use a lighter to deliberately "light the wok on fire". The oil/alcohol fume over high heat, just tilting the wok slightly it will "catch" the flame.

even water or soy sauce can and will cause sufficient spattering to cause/allow flaming.

that is why I asked the original poster if the chef used a lighter of some kind or simply tipped the wok and if the tipping was to cause flaming or if it was just part of shaking the wok.

[Ben Hong]

[dmreed]

Oil laden steam produced by the high heat of the wok will flame when meeting the open flame of the burner.

While I am at it, I will debunk the statement that the flames contribute to the wok hei taste and aroma of the food. NOT TRUE. It is NOT the food that burns or flares into flames, it IS the oil laden vapour or steam that has left the wok/food. Just basic elementary physics.

the steam or even the simple spattering of oil droplets will allow flaming.

I agree about the "taste" of flaming but I do think part of wok hay is the slightly charred food caused by the extremely hot oil/wok. the oil laden vapor contains the taste/smell of wok hay...in my experience, oil vapor by itself does not smell like wok hay unless, perhaps, it is the pre-heated/seasoned oil I mentioned earlier.

I surely enjoy these discussions and clarifications and I try to apply all the new techniques or information as soon as possible...which is usually pretty soon because I cook Asian food 3-5 times a week.

BTW last night, following my own earlier question, I tried a couple of drops of liquid smoke in some stir fried Asian vegetables to see if the taste/smell would approximate wok hay...the results were inconclusive...no smell or taste of the smoke so I will try again with a few more drops.

[Chris Amirault]

Perhaps I'm not understanding. What do you mean by "char"? I take that to mean cooking until the food has black spots or areas, like a steak with a crosshatch pattern of char from the grill. The majority of Chinese food cooked in a well-seasoned wok lacks char but has wok hei.

[dmreed]

Perhaps I'm not understanding. What do you mean by "char"? I take that to mean cooking until the food has black spots or areas, like a steak with a crosshatch pattern of char from the grill. The majority of Chinese food cooked in a well-seasoned wok lacks char but has wok hei.

actually the slight charring I was referring to are just very tiny charred specks...virtually all dishes with wok hay that I have eaten in restaurants or have cooked at home have had those very tiny specks...they are so small that they may easily be hidden even by a thin sauce. I definitely am not suggesting that large black charred spots are on the food.

it may be possible that very tiny bits of the food have charred in the oil and not appeared on the food itself. beef or pork cooked in a very hot wok with oil will definitely have at least tiny charred bits...I suggest that it would be impossible not to get the tiny charring!

for me, wok hay definitely has that slight charred smell and taste!

[Ben Hong]

The tiny black specks that you find in some dishes are actually bits of carbon burned off when a well-seasoned wok is heated to some very high temps, some would even dare call it "dirt" . Of course you could even say that it is evidence of wok hei achieved.

Semantics and terminology are words that could be at play here, hmmm? My idea of wok hei does NOT taste like charring, but it does taste like hot oil in very hot steel doing their "stuff" on the food that they meet. The idea of browning meats before cooking is not a commonly accepted practice, even for Chinese stew -like braises. You see except in purpose cooked dishes like smoked duck and skewered/bbq meats, etc., the presence of smokiness and charring is not acceptable in a dish. You ever hear of the yin/yang dichotomy? Charring is too, too much yang. Some would find it offensive.

Edited March 16, 2010 by Ben Hong (log)