Steam 1000 grams of white flour like steamed bread. After cooking, put it into a jar or pot and cover it tightly with plastic sheets to keep the temperature. Then put it in a dark, windtight place for fermentation, and white hair will grow in about 3 days. Brush off some white hairs, break them into pieces and put them in two clean containers. Pour into a container according to the ratio of1000g white flour with 300g water and120g salt and stir with a wooden stick to dissolve. Exposure to sunlight, stirring three or four times a day, about 20 days to make sweet noodle sauce. After the sauce is sun-dried, add a small amount of monosodium glutamate and white sugar, and steam on the pot for 10 minutes. The flour paste treated in this way has good color, fragrance and taste, unique flavor and can be preserved for a long time.