Wok Hei (镬气) — The Breath of the Wok

The term wok hei (Cantonese: 鑊氣) is both a practical description of an identifiable aromatic quality and a shorthand for the entire skill set of Chinese wok cookery at high heat.

Wok hei — literally 'breath of the wok' — is the complex, smoky, slightly charred aromatic quality imparted to food cooked in a screaming-hot seasoned wok over a ferocious flame. It is the single most discussed and least understood characteristic of Chinese restaurant cooking, and the principal reason that home stir-fries rarely achieve the depth of a professional kitchen. The compounds responsible for wok hei include Maillard reaction products from seared proteins and sugars, pyrolysis of residual fats on the seasoned wok surface, and partial combustion of volatile aromatic compounds at temperatures exceeding 300C. Grace Young in The Breath of a Wok devoted an entire book to its science and pursuit.

Wok hei is not a single flavor but a family of aromatic compounds that together produce the sensation of freshness and vitality that distinguishes restaurant Chinese from home Chinese. It is the culinary equivalent of a live flame versus a candle.