1. Material selection and flour extraction: potatoes with high starch content within 30 days after harvest are selected as raw materials. Removing frozen rotten, rotten lumps and impurities, repeatedly washing with water, crushing, pulping, fermenting, filtering, filtering starch and forming.
2. Ingredients: potato starch 100 kg with water content below 35%, 50 kg of water. First, put 5 kg of starch into the pot, then add warm water accounting for 70% of its weight to make it into slurry, then pour boiling water into the pot from the middle, and quickly stir it clockwise with a wooden stick or stirrer until it becomes a sticky ball.
3. Add alum to mix the flour: according to the ratio of 100 kg of starch and 0.2 kg of alum, grind the alum into flour and put it into the flour mixing basin, then pour the beaten flour into it, stir it evenly to make the water content of the mixed flour be between 48% and 50%, and keep the temperature of the flour at about 40℃ to ferment and decompose the remaining starch.
4. Boiling water leakage: first, add water to the pot until it is 90% full, and boil it, then put the mixed noodles into a leakage machine with the aperture of 10 mm to try to leak. When the diameter of the leaked vermicelli reaches 0.6 ~ 0.8 mm, at a fixed distance, it leaks into the boiling water pot and is taken out while leaking. The water in the pot is kept at the water level when it is put for the first time, and the water in the pot is controlled at the slightly opened water level.
5. Drying in cold water bath: take out the vermicelli leaked into the boiling water pot, put it in a cold water tank, insert a stick, put it in water at 15℃ for 5 ~ 10 minutes, and then take it out and dry it in a cool place at 3 ~ 10℃ for12 hours to enhance its toughness. Then put it in the sun to dry. When the water content reaches about 20%, it will converge into piles and take out the sticks to dry.