The proportion of frozen water in pressure cooker is 1: 3, and it can be cooked for 20 minutes after SAIC. Cooking in a common soup pot, the ratio of water to pigskin is 5: 1, that is, add 5 times of water to pigskin and cook for 60-80 minutes with low fire. Steam pigskin, the ratio of water to pigskin is 2: 1, and steam for about 70 minutes.