Wok hei (鑊氣), literally translated as "wok energy" or "breath of the wok," is a term in Cantonese cuisine referring to the distinctive charred, smoky flavor and aroma imparted to food when stir-fried in a very hot wok over an open flame.
The effect results from high-heat chemical processes including the Maillard reaction, caramelization, and the partial combustion of oils. It is facilitated by the shape and material of a seasoned carbon steel wok, rapid tossing of food through steam and vapor, and the brief ignition of aerosolized oil.
Wok hei is characteristic of Cantonese cooking and is not commonly emphasized in other regional Chinese cuisines.