焯水 (Blanching)
Pinyin: chāo shuǐ
Definition
Chao shui is the technique of briefly boiling ingredients in water (typically 30 seconds to 3 minutes) and then optionally shocking them in cold water to stop cooking. In Chinese cooking, it serves three distinct purposes: removing blood and impurities from meat (called 'flying water' or fei shui), par-cooking vegetables to set their bright color and remove raw bitterness, and pre-cooking dense ingredients to reduce stir-fry time. Nearly all Chinese meat stews and many stir-fries begin with a chao shui step.
Stove Parameters
Gas
Da huo (maximum) to bring water to a rolling boil, maintain at full boil during blanching
Use the largest burner at full power. The water must be at a vigorous rolling boil — 212°F (100°C) — before adding ingredients. For vegetables, the faster the water returns to a boil after adding food, the better the color retention.
Induction
Power level 9-10 (maximum) to boil, maintain at 8-9 during blanching
Induction boils water fastest of all stove types. Set to maximum and use a large pot. The rapid heat recovery is ideal for chao shui — water returns to a boil quickly after adding ingredients.
Electric
Maximum setting (10/10) to boil, maintain at 8-9
Bring water to a rolling boil on maximum heat. Electric burners are slower to boil but maintain temperature adequately. Use a large volume of water (at least 3 quarts per pound of food) to minimize temperature drop.
Ceramic
Maximum setting to boil, maintain at 8-9
Ceramic cooktops heat water efficiently. Bring to a rolling boil on maximum heat. Keep the pot covered until boiling to speed up the process.
Common Mistakes
- Adding meat to already-boiling water for impurity removal — for fei shui (meat blanching), start with cold water so impurities release gradually as temperature rises
- Not using enough water — use at least 3 quarts of water per pound of food so the temperature drop is minimal when food is added
- Blanching vegetables too long — most Chinese greens (bok choy, choy sum, gai lan) need only 30-60 seconds; overcooking turns them olive and mushy
- Skipping the ice bath for vegetables — plunge blanched greens into ice water immediately to stop cooking and lock in the bright green color
FAQ
What is the difference between chao shui with cold start vs. hot start?
Cold-start chao shui (placing meat in cold water and bringing to a boil) is used for meat impurity removal — proteins and blood coagulate slowly, releasing scum that floats to the surface for skimming. Hot-start chao shui (dropping food into already-boiling water) is used for vegetables and par-cooking — the rapid heat sets color and texture quickly. Using the wrong start method is a common error that affects the final dish quality.
Should I add salt or oil to blanching water?
For vegetables, add 1 teaspoon of salt and 1 tablespoon of oil per quart of water. The salt seasons the vegetables and raises the boiling point slightly, while the oil coats the surfaces to maintain a glossy appearance. For meat impurity blanching, do not add salt or oil — the water will be discarded along with the scum.
How long should I blanch common Chinese cooking ingredients?
Leafy greens (bok choy, spinach): 30-45 seconds. Broccoli and cauliflower: 60-90 seconds. Green beans: 2-3 minutes. Pork ribs (impurity removal): cold start, bring to boil, boil 2-3 minutes. Chicken pieces (impurity removal): cold start, bring to boil, boil 1-2 minutes. Tofu (to firm up): 2-3 minutes at a gentle boil.