How to make sweet potatoes into vermicelli?

A method for prepare vermicelli with sweet potato powder is as follow:

1, filtered with 0,7 ~1,5m hanging cloth, and filtered twice. The initial solution is thinner and the second solution is thicker. Two days after the filtrate enters the tank, drain the water in the tank, add 1/3 raw water, stir, filter again, and deposit the filtrate in a small tank.

2. When the tank body is completely clarified, drain the water, take out the surface oil powder, take out the lower starch, hang it into a powder pile and expose it to the threshing floor. When half of the water in the powder pile evaporates, cut the powder pile into several parts and expose it to the sun. The threshing floor is located in the leeward and sunny place to prevent dust pollution.

3. Add100g of alum to 500g of starch, mix in 2500 ~ 3000g of cold water, and put it into a basin. Put the pot into the pot and bring it to a boil, stirring constantly until it is 80% to 90% mature. The paste can be used for 20 kilograms of vermicelli.

4. Try it before it leaks to see if the dough is suitable. If the leaked vermicelli is not coarse, fine and discontinuous, it is appropriate. The following strips are too fast and broken, indicating that the starch paste is too thin, so it should be mixed and rubbed with dry starch to make the surface toughness moderate; It is difficult or too slow below, the thickness is uneven, the surface starch is too dry, and some wet starch should be added.

5. Take the vermicelli to the leeward and sunny place, dry it and pack it to get the finished product.