Looking at toughness, although authentic sweet potato vermicelli can't be cooked for a long time, the texture of dried sweet potato vermicelli is very brittle, and it is very easy to break when we hold it in our hands. Burning method is also a common method to identify the authenticity of vermicelli. Authentic sweet potato vermicelli will have no crackling sound or pungent smell after being ignited, only a faint paste smell. The easiest way to tell whether a fan is true or false is to boil it in water. Authentic vermicelli is particularly easy to cook, and it can be softened in about 5 minutes.