Slow cooking in plenty of water or stock over low heat, with the broth kept.
Diao tang is a craft for refining stock: finely chopped chicken, lean pork or similar is held in hot stock just below the boil so that it gathers fine impurities, then lifted out and the stock is strained, giving a clear stock. Milky stock, its counterpart, is made from fatty bones or trotters and turns white; the color comes from fine fat droplets held by dissolved proteins. Cantonese cooking grades stocks as top, superior and second stock, and the “water” in the Sichuan banquet dish kaishui baicai is a carefully made clear chicken stock. The available material gives no date for the craft.
What
Diao tang is the craft of refining stock. A clear stock is “hung”: finely minced meat is held in hot stock that is not boiling so it gathers impurities, and is then strained out. Milky stock is made by boiling fatty bones hard; its milky color comes from fine fat droplets held by dissolved proteins.1,2,4
When
The available material gives no date for diao tang, and no old text describing it was found.1,2,3,4,5,6
Where
The available material does not tie diao tang to one place. Cantonese cooking grades stocks as top, superior and second stock; the Sichuan banquet dish kaishui baicai uses a carefully made clear chicken stock.1,6
How
Clear stock preparation appears in 1 food article and 1 Sichuan food article from 2020: hen, duck, ribs or similar are simmered into stock, then minced lean pork and chicken are stirred in just below the boil to gather impurities, lifted out, and the stock is strained through cloth. Performing diao tang 2 times is called double diao tang. Milky stock: fatty bones or trotters are brought to a boil over high heat, then kept at medium heat for 2–3 hours.1,2,3,4
Why
Milky stock turns white because fine fat droplets are held in the liquid by dissolved proteins.4
Impact and influence
The Sichuan banquet dish kaishui baicai is an example of diao tang: its “water” is a carefully made clear chicken stock.5,6
Chinese Wikipedia retells a Qing court tale connecting chef Huang Jinghe with kaishui baicai and says that Luo Guorong took the dish to Beijing. It gives no year.
Told in: A Qing court tale retold in the Chinese Wikipedia entry on kaishui baicai, which gives no year.