Hanging dry powder means that wet powder is firmly attached to the ingredients. Not only potato towers, but also others, such as fried eggplant, bananas and apples, can be dried directly with wet powder or hung with paste. Because the ingredients are rich in water, they fall off easily. After the dry powder is hung, it will form a shell on the potato tower or other ingredients, which is crisp outside and tender inside, and has a better taste.