Flour (wheat flour) is a staple food in most parts of northern China. There are many varieties of food made from flour, with various patterns and different flavors. We often say "flour" refers to wheat flour, that is, flour made from wheat, "high-gluten wheat flour" Names like this refer to what we usually call flour. According to performance and use, wheat flour is divided into special flour (such as bread flour, dumpling flour, biscuit flour, etc.), general-purpose flour (such as standard flour, strong flour), and nutrient-fortified flour (such as calcium-enhanced flour, iron-rich flour, "7+1" "Nutrition-enhanced flour, etc.); According to the precision, it is divided into special first-class flour, special second-class flour, standard flour, ordinary flour, etc.; according to the strength of gluten, it is divided into high-gluten flour, medium-gluten flour and low-gluten flour.