Handmade alum-free vermicelli formula: 80 kg of sweet potato starch (or potato and mung bean starch), 20 kg of cassava starch, 0.6-0.8 kg of gluten source, 0.5 kg of salt and 300-500 kg of 55-degree warm water. Technology: Dry-mix the starch and gluten evenly, add warm water to the salt, then mix with the starch to form a paste, and keep the temperature for 30 minutes. Grease spinneret, preheat, add starch paste, shake well, spread it out, put it in a boiling pot, steam it until it turns white, pour in hot water, scald the vermicelli until it is transparent, pour out the hot water, take out spinneret after one minute, put it in a cold sink, and expose the vermicelli after cooling. Put some oil between each piece of paper, fold it, vacuum package it or dry it for sale.