This is generally not recommended. First, many protein powders on the market have added ingredients (regardless of impurities), which will change soon after hydrolysis, such as sugar fermentation. Second, the pollution problem is inevitable. If directly exposed to the air at room temperature, one hour is enough to make protein deteriorate, and in severe cases, it smells like rotten eggs. Third, to avoid the above problems, the operation is troublesome, it needs to be preserved for a long time, and it needs to be brewed at high temperature, immediately sealed and refrigerated, and heated when eating.