Longkou vermicelli is soaked in hot water or warm water. If soaked in hot water, it will soften quickly and taste better. Longkou vermicelli usually takes 20-40 minutes to soak in hot water. If you are in a hurry, you can use warm water, usually 15-20 minutes.
See the packing instructions for details. Different kinds of vermicelli will have different soaking time. Note that the soaking time should not be too long, otherwise it will affect the taste of vermicelli and will burst.