The best vermicelli is made of mung bean, corn starch or sweet potato starch, but the quality is not as good as mung bean vermicelli, because mung bean has the most amylose, which is not easy to rot when cooked and tastes the most greasy. Similar to spaghetti, it is sold after drying, and it is best to soak it in water before eating. The diameter of vermicelli is generally about 0.5 mm, which is why it is called "silk".