When using raw animal food such as fish, shellfish and chicken, it is necessary to boil it without fail to solidify water-soluble protein and thereby to prevent it from dissolving in water; otherwise, the stock will become cloudy and unpleasing to the eye.
魚介類や鶏肉など、生の動物質を使うときは、必ず一度茹でて水溶性たんぱく質を凝固させ、溶出を防止しないと汁が濁り、見た目が悪くなる。