Bai zhuo (白灼, literally white scalding) is the Cantonese technique of briefly poaching food — typically vegetables and seafood — in a light aromatic broth or salted water, then finishing with a drizzle of hot soy sauce and sizzling oil. The technique exemplifies Cantonese cooking philosophy: ingredients of impeccable freshness, handled minimally, dressed simply so that the ingredient's natural flavour is the point. Bai zhuo Chinese greens — morning glory, choy sum, or gai lan in a pool of oyster sauce and hot oil — is one of the most frequently ordered dishes in any Cantonese restaurant.
Bai zhuo is one of the purest expressions of Cantonese freshness doctrine. It transforms greens into something simultaneously simple and profound — the clean sweetness of the vegetable against the umami of oyster sauce and the fragrance of the hot oil sizzle.
The white-scalding sequence: 1. Bring a large volume of water to a rapid boil. Salt lightly and add a small amount of oil (prevents greens from discolouring). 2. Add greens or seafood. For gai lan or choy sum: 1-2 minutes. For shrimp: 2-3 minutes. For squid: 60 seconds. 3. Remove immediately when just cooked — greens should be vivid green and slightly resistant to the bite. 4. Arrange on a platter. Pour Lee Kum Kee oyster sauce or light soy sauce over. 5. Heat 2 tbsp of oil in the wok until just smoking — pour over the dressed greens. The oil sizzles on contact with the soy sauce, creating an aromatic bloom. The sizzle (淋油, Lin You): The final pour of hot oil releases volatile aromatic compounds in the soy sauce and oyster sauce, creating a brief aromatic burst.
Adding 1 tbsp of neutral oil to blanching water prevents discolouration in green vegetables. Gai lan benefits from a 30-second rest off-heat before plating — residual heat continues cooking without overdoing it.
Overcooking greens: Bai zhuo greens should retain slight crunch and vivid colour. 1 minute too long = grey, limp vegetables. Insufficient water volume: A small pot of water that greens overwhelm will drop below boiling and produce a steamed rather than blanched result.
Fuchsia Dunlop, Land of Fish and Rice (2016); Eileen Yin-Fei Lo, Mastering the Art of Chinese Cooking (2009)