1. Choose sweet potatoes. Choose sweet potatoes with a smooth surface, no pests, no greenheads, and a good size.
2. Wash, put the selected sweet potatoes into the basket, put them in water, wash away the soil and impurities, and cut off both ends of the sweet potatoes.
3. Crush. The washed sweet potatoes should be crushed in time. A 380 or 440-type powder mixer driven by a 195-type 12-horsepower diesel engine is used to add water while beating.
4. Filter. Filter with 0.7-1.5 meters of pulp cloth, and filter twice. The first time diluted the solution, and the second time it was more concentrated. After the filtrate has been in the pool for 2 days, drain the water in the pool, add 1/3 of the original water, stir evenly, filter again, and put the filtrate into a small pool for precipitation.
5. Exposure to the sun: After the pool is completely clarified, drain the water, remove the oil powder on the surface, take out the lower starch and hang it into a dough, and put it in the drying field for exposure. After half of the moisture in the powder block has evaporated, cut the powder block into sections and expose them to the sun. The drying field is located in a leeward, sunny place for sweet potato flour to prevent dust pollution.
6. Make a paste. Add 500 grams of starch to 100 grams of alum, add 2500 to 3000 grams of cold water, and put it in a basin. Put the pot in the pot and bring it to a boil, stirring constantly, until doneness reaches 80% or 90%. The beaten paste can make 20kg of starch noodles.
7. Leakage. You can try it before leaking the thread to see if the powder set is suitable. If the bar is too fast and the bar breaks, the slurry is too thin. It should be mixed with dry starch, and then kneaded into a moderately tough dough; if it is difficult to beat or the speed is too slow, the thickness is uneven, and the surface powder is too dry, it should be added. some wet starch. It is recommended to adjust the powder quantity before leaking the line. The dough temperature is preferably 30 to 42 degrees Celsius. Prepare 2 pots (model 8), 2 cold water tanks, and a medium 48-hole colander. When the wire is leaking, it should be stirred evenly, and the water temperature is 50 ℃. When you leave your hand, grab a ball (handle) and let it fall naturally, if it keeps going down, the line will miss. When the line leaks, prepare a pot of boiling water. The water in the pot boils and the line leaks. When the bottom of the pot comes to the surface again, it's ready to serve. After a cold water tank has cooled, tie it into a bundle by hand and place it on a wooden stick. After the other cold water tank has cooled, continue to swing until the fan comes loose. Then put it indoors and take it out to dry after it cools down.
8. Dry silk. Take the fan to a leeward, sunny location, dry it, and pack it into a finished product.