1. Smell it. If there is a pungent smell, it means that the vermicelli is broken or there is something wrong. Normal vermicelli smells like sweet potato.

2, take a look again, the real vermicelli thickness is uneven, and vice versa.

3. It's on sale again. Let's fold it by hand. Good vermicelli is easy to break, accompanied by a crunchy sound. If it is willful, don't buy it, because it may contain some rubber additives.

4. Then roast it. Let's take out a vermicelli first and bake it with a lighter. Because it is made of starch, there is no smell and crack after ignition, and it will carbonize to ashes when burned.

5. Finally, a reminder, if it is glue, it is easy to ignite, and there will be a pungent smell during the burning process, and it will be granular after burning. Don't buy such fans.