1, cooking time: The longer the beef is stewed, the darker the color. Cooking for a long time will decompose the protein of beef and release prominent elements, which will lead to the black color of soup.
2. Seasoning used: Different seasonings will also affect the color of beef soup. Some recipes contain a lot of soy sauce or other dark seasonings, which will also make the soup black.
3. Use of beef bone or bone marrow: Some beef soup will use beef bone or bone marrow to increase the flavor and concentration of the soup. These bones usually contain a certain amount of bone marrow and bone marrow fat, which will make the soup turbid and sometimes appear white or milky white.