Qing tang (清汤, clear stock) is the master clear stock of Shandong and Chinese court cooking — the most laboriously produced stock in Chinese cuisine, achieved by a process of repeated clarification using minced meat (the technique called sao tang, 扫汤, literally sweeping the broth). The result is a stock of crystalline clarity and exceptional depth of flavour — used as the base for the most refined soups and sauces in Shandong and Huaiyang cooking, including wensi tofu, lion's head meatball clear version, and superior wonton soup.
The initial stock: Simmer chicken (whole or carcasses), pork bones, Jinhua ham, and dried scallop in cold water for 3-4 hours. Skim repeatedly. Strain. The clarification (sao tang technique): In the Shandong tradition, clarification uses minced lean pork or chicken mixed with egg white and cold water — a paste that is added to the warm (not boiling) stock and stirred. As the stock heats, the proteins in the minced meat coagulate and trap the suspended particles in the stock, carrying them to the surface as a raft of foam (mo, 沫). This raft is then carefully removed. The process may be repeated 2-3 times for perfect clarity. Alternative: A single clarification with an egg white raft (Western technique) achieves approximately 80% of the clarity of the traditional sao tang method.
Fuchsia Dunlop, Invitation to a Banquet (2023); Eileen Yin-Fei Lo, Mastering the Art of Chinese Cooking (2009)