Vol. XXII · Stocks, Soups and Sauces Plate 2 of 11Chinese stock, 清汤, 奶汤, 高汤, 上汤, clear soup, milky broth, 白汤, 猪骨汤, 鱼汤, tonkotsu, emulsion, gelatin, 吊汤, 扫汤MF

Chinese Stocks.

A fish head fried and boiled hard for twenty minutes turns its water white as milk. A chicken simmered gently for hours stays clear as tea. Both are deliberate.

Chinese cooking prizes stock (汤, 高汤, 上汤) as the base of soups, braises and sauces, and makes two opposite kinds. 清汤 is clear: chicken, pork and ham simmered at the barest quiver for hours, skimmed constantly, then clarified by 吊汤 or 扫汤 — stirring in minced chicken (red mince, then white) which coagulates and gathers the fine particles as it rises, the same idea as a French consommé raft. The finest 清汤, like the 开水白菜 broth of Sichuan, looks like plain water and tastes intensely of chicken.

奶汤 is the opposite: pork bones, chicken carcasses, or fish heads first fried in a little fat, then boiled at a full, rolling boil. The turbulence breaks the fat into fine droplets; gelatin and dissolved proteins coat them and keep them from merging (X.2), so the broth becomes an opaque white emulsion that scatters light like milk (X.1). The more gelatin, fat and vigorous the boil, the whiter and creamier it gets — the principle behind 猪骨汤, Cantonese fish soups and Japanese tonkotsu ramen. The workshop boils a pot.

Below: a teaching index of how white a pork-bone broth becomes against hours, at a gentle simmer or a rolling boil, with the gelatin from the bones (as in XXII.1) stabilising the emulsified fat.

What you will learn
Workshop
Teaching model: share of fat emulsified = 1 − exp(−a × hours), with a = 0.05 per hour at a simmer and 1.0 per hour at a rolling boil; whiteness = emulsified share × the gelatin's stabilising power (gelatin ÷ 1.5 %, capped at 1). Gelatin from pork bones as in XXII.1.

Quiet heat for clear, fierce heat for milk

In this teaching model, after three hours a pork-bone broth at a rolling boil reaches a whiteness of about 0.95, while the same pot at a gentle simmer stays at 0.14. The boiling broth has about 2.4 % gelatin to hold its droplets. So for 奶汤, boil hard with the lid off and top up with boiling water; for 清汤, never let it bubble, and skim.

Methods. 奶汤 from fish: fry fish heads and bones in a little lard or oil until golden on both sides, pour in boiling water, and boil hard for 15–20 minutes until white; strain, season with salt and white pepper, add tofu or greens. Pork-bone 奶汤: blanch bones, then boil hard 3–6 hours. 清汤 (上汤): simmer an old hen, pork and Jinhua ham very gently for 4–6 hours; strain; stir in a paste of minced chicken and cold stock, bring slowly to just below the boil and let the mince rise and set, then strain through cloth; repeat with white mince for a crystal-clear broth.

At the stove

Divide a pot of pork bones and water into two: boil one hard, uncovered, and keep the other at a bare simmer, for two hours each. Compare their colour in glasses held to the light.

开水白菜, "cabbage in boiling water", was created by a Sichuan chef for state banquets: a few tender cabbage hearts in what looks like plain hot water — a 清汤 so clarified that the joke is in its appearance.

Terms

清汤
Clear stock: simmered gently and clarified.
奶汤
Milky stock: boiled hard so fat is emulsified by gelatin.
吊汤 / 扫汤
Clarifying a stock by setting minced meat in it.
上汤
The finest Cantonese stock, of hen, pork and ham.
清汤: a bare simmer, skimming, and minced meat to clarify. 奶汤: a rolling boil breaks fat into droplets that gelatin holds in a white emulsion. Same bones, opposite heat.

Sources

  1. A teaching value chosen for the course: the right order of magnitude and shape, not a measurement of a particular food.
  2. H. McGee, On Food and Cooking: The Science and Lore of the Kitchen, 2nd ed., Scribner, 2004.