Cold noodle is a kind of pure starch food, which is made of starch in wheat flour. If you look at flour from the perspective of cold noodles, flour is composed of gluten and starch. So to make cold noodles, you must first separate gluten from starch. The separation of gluten and starch is washing your face, which is why you must wash your face when making cold noodles. So although cold noodles are made of wheat flour, they are not made of flour directly, but made of starch after washing your face. Of course, there are many kinds of starch, but their uses are different. For example, pea starch is most suitable for bean jelly, and sweet potato starch is most suitable for vermicelli. Similarly, wheat starch is most suitable for cold rice noodles, and no other starch can make cold rice noodles soft, translucent, smooth and firm.