Wok Hei is the smoky aroma of Cantonese food, achieved through stir frying at extremely high temperatures. Translating to ‘breath of a wok’, Wok Hei is one of the cornerstones of Cantonese cooking, and provides the flavour most associated with Chinese food in Western countries. In fact, missing Wok Hei is most likely the reason why your home stir fries don’t taste quite the same as dishes from your favourite Chinese restaurant. But what exactly is Wok Hei, and how is it achieved?
We’ve all seen Wok Hei in action, with the pan catching alight as the food is skilfully tossed. Wok Hei requires two important factors: a seasoned wok and extremely high heat. Traditional woks are made from cast iron, while modern day woks are generally made from carbon steel. Your wok must be seasoned before use to develop a patina of hardened oil, to prevent the food from sticking and to impart a smoky flavour. The shape of a wok is also important for Wok Hei, as it allows food to be tossed in its own steam. This speeds up cooking and concentrates flavour, and, as the food hits the hot base of the wok, the surface moisture on the food from the steam evaporates and the process repeats.
High heat is the other important factor for Wok Hei. The smoky flavour associated with Wok Hei is a result of three different processes: the caramelisation of sugars, the Maillard reaction (in which reducing sugars react with amino acids, creating new flavour compounds) and the smoking of the oil. All of these processes require temperatures as high as 300 degrees celsius, so extreme temperatures are crucial to achieving Wok Hei. This is why constant stirring and tossing is also important when stir-frying, to prevent the food from burning at such high temperatures.
We must also note here that it is stir-fry sacrilege to heat your oil up with your wok. You must instead add cold oil to your wok when it’s just smoking hot, then immediately add your ingredients – this way, the oil does not begin to chemically decompose due to the high temperatures, giving the food an unpleasant taste. The amount of oil used is also important when it comes to achieving Wok Hei. The ingredients will almost shallow-fry if too much oil is used, while with too little oil, Wok Hei cannot be achieved.
So, while you may have your best seasoned wok at home, you are unlikely to be able to achieve Wok Hei in a home kitchen, as most home stoves don’t have sufficient BTU output to reach these high temperatures. This does makes it even more special to experience these delicious flavours when eating at a Chinese restaurant, but it is frustrating to know that you're likely unable to recreate it at home. However, there are a lot of tips and tricks you can take from the art of creating Wok Hei to up your home stir-fry game.
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How do I season my wok?
To season your wok you must create a ‘patina’. This is a layer of hardened oil that acts as a non-stick surface, which both protects your wok from corrosion and imparts a smoky flavour onto food cooked in it. You must first scrub your wok with a metal scourer to remove its anti-rust layer. Then, get your wok on the hob on the highest heat possible and watch it burn – if made of carbon steel it will change colour multiple times before finally going matte grey. Allow the wok to cool, then coat the inside with a thin layer of oil – use an oil here with a high smoking point, such as sunflower oil. Get your wok back on the heat until the oil begins to smoke. When it stops smoking, your patina has been created, so your wok is seasoned and ready to use. Some people like to add aromats such as garlic, chill, ginger or spring onion when heating the wok, which once removed then leave a very faint flavour on the interior and help ensure dishes are sper-charged with flavour.
Why does the pan catch fire during Wok Hei?
This is perhaps what most people see when thinking of Wok Hei, a pan alight with flames a foot high. These flames appear as small droplets of oil in the air catch alight as they come into contact with the hob's flames, and they help to food achieve its smoky taste.
Top tips for stir-frying?
- Get your wok really hot – your wok needs to be extremely hot before you even add your oil; quick cooking is crucial for stir-fry, so the food is crispy and caramelised but not overcooked
- Don’t use too much oil – using too much oil at such a high heat may cause your food to almost shallow-fry, which is not the desired effect when stir-frying
- Keep the food on the move – constantly stirring and tossing the ingredients in the wok is important to stop the food from burning
- Don’t overcrowd the wok – if your wok has too much in it, the food will steam rather than fry and you’ll end up with a soggy stir fry; less food in the wok also makes non-stop stirring much easier
What is the best restaurant for Wok Hei in London?
Chef Fei Wang's dishes at Hutong are definitely some to check out, to experience the Sifu's Wok Hei skills. Otherwise, take a look at our list of the best Chinese restaurants in London for some other places to enjoy the delicious flavours of Wok Hei.
Are you a Chinese food lover? Check out our guide to the best dim sum restaurants in London for dumplings to die for. Or, if you’re looking to improve your kitchen skills, take a look the UK's best cooking classes.
Written by: Niamh Parker