Basic Chinese Cooking Lore: Hot pan cold oil 热锅冷油

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When learning to use an iron wok, one of the first pieces of advice that you will hear is “Hot pan, cold oil” 热锅冷油。The conventional wisdom is that this makes food less likely to stick. I’ve found it to be true with cast iron woks as well as hammered steel (forged) woks and especially so when cooking proteins like meat 荤菜 and starchy foods like noodles 面食 or rice.

 

If you have ever had trouble with your stir-fry dishes getting torn up by sticking to the pan, it might be helpful to have a brief review. Early this morning I found a couple of YouTube videos which provide a clear one as well as offering a quick glimpse of the underlying science. (Her Chinese is very standard; she speaks native speed but very clearly.)

 

Thought I would post links so you could have a look. (I’m currently living in exile in the US without a decent stove or wok and cannot demonstrate for you in my own kitchen.) These videos are by a home cook named Rosa, using her well-seasoned cast iron wok. She demonstrates by simply frying an egg under different conditions. She also discusses care of her wok.  

 

https://www.youtube.com/watch?v=OD5MFtNOcc8  

 

In this second video, she expands her experimentation and explanation to other types of pan, including stainless steel and ones with a non-stick coating.

 

https://www.youtube.com/watch?v=ES8-OajTFTE 

 

 

 

 

 

 

 

 

 

In case your links don’t work,

Spoiler

 

paste these titles into your browser’s search bar:

Rosa厨房研究报告: 科学防粘锅（上）炒什么都不粘

Rosa厨房研究报告: 科学防粘锅（下）不锈钢锅、不粘锅

 

 

Then go watch Chef Wang Gang 王钢厨师 at work to see a restaurant chef doing the same thing with an added twist. He uses the “double oil” technique, first liberally oiling the hot wok to “seal” it, pouring that out, then coating it a second time before frying the food. This promotes a non-stick cooking surface without too much oil actually getting incorporated into the meal. (You can jump to the 2-minute mark to skip the prep stages if you wish.)

 

https://www.youtube.com/watch?v=68v5mGdE978  

 

 

 

 

 

 

 

 

 

 

In case… your link doesn’t work,

Spoiler

 

paste this title into your browser’s search bar:

“Master Chef Wang Gang teach you how to cook famous Chinese food - Fish-Flavored Shredded Pork.”

 

 

The "hot wok, cold oil" technique is one of several factors that can help your pan-fried Chinese dishes come out better. (When Chinese say "cold oil" they really mean room temperature. It doesn't need to come out of the fridge.)

 

[xinoxanu]

Also known as 滑锅 or "longyau"(?) in cantonese... which is basically the catchphrase of any Chinese Cooking Demystified video, such as: https://youtu.be/WujehK7kYLM?t=189. I really love that channel, Chef Wang's (I mean, he's from Sichuan - we are basically family!) and Dianxi Xiaoge's. Do check these out!

 

This technique, however, is not exclusive to China. My French grandmother always puts the emphasis on cooking with quite a hot pan + room temperature fat (butter, oil) for the best results. Not wok-level hot, mind you, since you always gotta be careful about smoke points (olive oil in particular, and butter separates rather fast at high temperature so you definitely need grandma-level experience there) - but hotter than the norm nevertheless.

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This technique, however, is not exclusive to China. My French grandmother always puts the emphasis on cooking with quite a hot pan + room temperature fat (butter, oil) for the best results.

 

Generally speaking I agree with your French grandmother. The exception would be when using a non-stick pan, such as one coated with Teflon. They tend to do best when only medium hot. 

 

As you say, smoke point is important. It is useful as an indicator of when the wok is hot enough for a stir-fry, when the oil in the pan is between its smoke point 冒烟点 and its fire point 燃点. Start cooking when there are early wisps of smoke (not billows of smoke.) Rosa's Kitchen Research Report 厨房研究报告 talks about that in another of her videos. (Click for link.) That's the source of this table. 

 

 

She doesn't include olive oil or butter, which can definitely add lots of flavor to a dish. I cannot imagine Jacques Pepin or Julia Child making anything without a big knob of delcious butter (or maybe two.) But they are not used much in Chinese frying because the smoke point is only around 200 C and 150 C respectively. Indian ghee (clarified butter) doesn't break down until about 250 C, which makes it suitable for high-temperature frying. 

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Also known as 滑锅 or "longyau"(?) in cantonese... 

 

@xinoxanu-- I watched the video a couple times. Do you think he could be saying “leng you” 冷油 as colloquial shorthand for 热锅冷油？After all, it is a well known and frequently used set phrase. 

[xinoxanu]

6 hours ago, abcdefg said:

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Also known as 滑锅 or "longyau"(?) in cantonese... 

 

@xinoxanu-- I watched the video a couple times. Do you think he could be saying “leng you” 冷油 as colloquial shorthand for 热锅冷油？After all, it is a well known and frequently used set phrase. 

 

I am not sure.

 

Dude's wife is Cantonese so at the very least "longyau" (or the closest written approximation) is one of the available Cantonese dialectal pronunciations. It's also worth noting that that word is always pronounced in the same way and their video subtitles (made by her I reckon) support this.

 

This is a somewhat puzzling term that not even Google can resolve based on this conversation, but two natives over there seem to believe "longyau" is the Cantonese pronunciation of "熱油", not "冷油".

 

Idk, Cantonese is a whole other world for me so I am really hoping that someone pops in to clarify this since now I am curious!

 

 

[Balthazar]

@xinoxanu: 滑锅 seems to be correct, here it is straight from the horse's mouth.

 

And as usual, thanks for the great write-up, @abcdefg!

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Thanks, guys. I learn something new every day. 

[Michaelyus]

On 3/11/2021 at 10:57 PM, xinoxanu said:

Also known as 滑锅 or "longyau"(?) in cantonese

 

?油 long2 yau4 is the generally accepted form, ? being the Cantonese form of Standard Mandarin 漱, to rinse or swirl. 

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8 minutes ago, Michaelyus said:

?油 long2 yau4 is the generally accepted form, ? being the Cantonese form of Standard Mandarin 漱, to rinse or swirl. 

 

Thank you @Michaelyus -- That's what I was looking for. Answers my question.