The skin of steamed dumplings is scalded with hot water.

Cold water dough is a kind of water-mixed dough mixed with water at a temperature below 30 degrees, commonly known as cold water surface. Because the flour is mixed with cold water or low-temperature water, protein in the flour can't undergo thermal denaturation, thus forming more and stronger gluten. Starch does not swell and gelatinize at low temperature, so the dough formed is firm, tough, tensile and stiff, also known as "dead noodles". The characteristics of cold water surface are that the finished product is white in color, refreshing and chewy, and not easy to break. Generally suitable for boiled and baked varieties, such as jiaozi, noodles, spring rolls, pearl soup, pancakes, etc.

Hot water concord is suitable for making steamed dumplings, steamed dumplings, pot stickers and oil cakes. The water temperature of dough is generally 60- 100 degrees. Under the action of hot water, protein in flour coagulates and decomposes water, so gluten is destroyed, and starch absorbs a lot of water and expands into paste to decompose monosaccharide and disaccharide. Therefore, the hot water dough is waxy and weak, and the finished product is translucent and has poor color, but it is delicate, sweet and easy to mature after heating.