Wok hei is a concept from Asian cuisine that refers to the unique flavour, aroma and texture created when cooking in a very hot wok. The term originates from Cantonese and literally means “the breath of the wok”. Wok hei is seen as the hallmark of perfectly stir-fried food.

What is wok hei?

Wok hei is the result of intense heating of ingredients in a hot wok, where oil, heat and movement come together to create a unique depth of flavour. The temperature is so high that the oil begins to smoke and the ingredients quickly caramelise on the outside. This process gives dishes their distinctive aroma and a subtle smoky taste. The term is used to describe dishes that have this particular layer of flavour. Wok hei is therefore not an ingredient or a technique on its own, but the outcome of the right conditions during stir-frying.

How does wok hei develop?

The creation of wok hei depends on three key factors: high temperature, precise timing and constant movement.

• Extremely high temperature: The wok must be searing hot (over 200 °C) before adding oil and ingredients. Only then can the oil briefly smoke and develop that characteristic flavour.
• Contact with the flame: In professional kitchens, the wok is used over an open flame. When the wok is tossed, small amounts of oil drip into the fire, causing it to flare up and briefly touch the food. This momentary combustion gives dishes their distinctive smoky flavour.
• Chemical reactions: Two important processes occur during stir-frying, the maillard reaction (browning caused by heat between sugars and amino acids) and the caramelisation of natural sugars. Together, these create a rich, complex flavour.
• Quick cooking: By keeping the ingredients constantly in motion, they cook evenly and retain their texture. The outside gains flavour, the inside stays juicy, and vegetables remain crisp.

When cooking at home, it’s important to preheat a carbon steel or cast iron wok thoroughly before you start. Work in small batches so the temperature doesn’t drop too quickly. An overcrowded wok prevents wok hei from forming. It’s best to use oils with a high smoke point, such as peanut, sunflower or grapeseed oil, as these can handle the heat without turning bitter.

Why is wok hei special?

Wok hei is special because it’s difficult to reproduce without the right heat and technique. It represents craftsmanship in Asian cooking and is often regarded as proof of proper stir-frying. The combination of smoke, umami (that deep savoury taste) and caramelisation results in a complex flavour that can’t be achieved with any other cooking method.

Beyond flavour, wok hei also affects the aroma and texture of a dish. Vegetables stay crisp, meat develops a slightly charred edge, and sauces take on a delicate smoky note. This combination of qualities makes wok hei an essential element of authentic stir-fried dishes.