About ten minutes. According to the food industry, gouache tastes best when cooked for about ten minutes. Gouache is a famous snack of Han nationality, which has good color, fragrance and taste. Many people only know hot and sour powder. In fact, there are two kinds of hot and sour powder: one is gouache, which is made of sweet potato starch; The other is "dry powder", that is, dry powder strips processed into vermicelli.