The science of wok hei

Flames inside the wok. Cooks chase wok hei: Cantonese for “breath of the wok”. It’s a smoky taste only fierce heat can make. Searing steel dries each grain, so it browns and chars a little. Engineers filmed chefs and timed every toss: almost three a second. Each toss lifts the rice off the metal to cool, so it can brown, not burn. Tossing flings oil into the heat too, and singed oil adds the smoke. And the flames? Skilled cooks tip them in for a moment. Chinese migrants brought stir-frying and wok hei to Thai cooking. We tell you everything you need to know about Bangkok. Follow for more!

Wok hei, Cantonese for “breath of the wok”, is a smoky taste only fierce heat makes: searing steel browns the food, fast tosses (almost three a second) let it brown without burning, and singed oil adds smoke.

• Wok hei (鑊氣, Cantonese, literally “breath of a wok”) is the complex charred aroma of Cantonese stir-fries. It needs intense heat, hard to reach without a commercial cooking range (MICHELIN Guide, 2016).
• Its basis is caramelising sugars, Maillard browning and smoking oil; the searing heat dries the surface of each piece or grain of rice so it can brown (MICHELIN Guide, 2016; Ko and Hu, 2020).
• Engineers at Georgia Tech filmed five professional chefs and measured the wok's position in every video frame: they tossed about 2.7 times a second. Rice that stays still could burn; in the air it gets time to cool (Ko and Hu, 2020).
• Tossing throws oil droplets into the air, and the smokiness comes from intense heat and singeing oil (Saporito et al., 2026). Skilled chefs momentarily toss the flames into their woks (MICHELIN Guide, 2016).
• Before Chinese migration, Thai cooking focused on grilling, boiling and fermenting; Chinese migrants introduced stir-frying and the idea of wok hei (Tourism Authority of Thailand, 2026).

Behind the Dish
We tell you everything you need to know about Bangkok. Follow for more!

Sources:
– Ko and Hu (2020): The physics of tossing fried rice. Journal of the Royal Society Interface 17(163):20190622 (Georgia Institute of Technology): https://pmc.ncbi.nlm.nih.gov/articles/PMC7061713/
– MICHELIN Guide (12 October 2016): What is… wok hei?: https://guide.michelin.com/en/article/dining-out/what-is-wok-hei
– Saporito et al. (2026): Occupational Exposures in the Culinary Underbelly – Air Pollution in Restaurants. Environmental Science & Technology 60(26):18723–18732: https://pmc.ncbi.nlm.nih.gov/articles/PMC13348163/
– TAT Newsroom (16 February 2026): Silk Road on a Thai Plate: https://www.tatnews.org/2026/02/silk-road-on-a-thai-plate/

Facts and sources: https://soibysoi.com/episodes/the-science-of-wok-hei

Illustrations: the rice grains, oil droplets and smoke are drawn large, not to scale.
General information. Rules, prices and opening hours change: check them before you go.
All music and sound are original, made for the channel.
The narrator’s voice is AI-generated.

#bangkok #thailand #bangkoklife #thaifood