The first step is to cook the beans. Wash the selected soybeans in cold water, then immediately put them in a pot and add drinking water until the soybeans are about two fingers deep. Then start cooking the beans like rice, until the beans taste slightly floury. Remove the beans and place them on a dice overnight to cool thoroughly.

After the soybeans are cooled, start frying the noodles. Wrap the soybeans with a thin layer of noodles evenly so that they do not stick to each other. If the beans are too cold to mix, pour a small amount of the reserved bean cooking water on the soybeans until they can be coated with dough.

The second step is to lay three or four layers of newspapers and periodicals under wood board or some materials with good breathability (not suitable for glass or plastic), and then lay a layer of clean tissue paper or wrapping paper on top of the newspapers and periodicals. Spread the mixed soybeans evenly on the tissue paper, about one finger thick. Spread a layer of paper with good breathability on the spread soybeans. The windows and doors of the house where the beans are kept should not be opened frequently, and a hot, humid environment should be maintained as much as possible. When the temperature is low in spring, the beans can be covered with paper and a layer of towels can be placed on the paper to facilitate the fermentation of the soybeans.

Watch the soybeans until the third day. If the soybeans turn black, it means they have been covered properly. If they become sticky, it means the humidity is high. You can tear off the paper covering them. After 3 days, black hairs will grow on the soybeans. After another day or two, the black hairs will turn into green mold. Put the beans covered with green hairs in a dice and put them in the sun to dry, which will take about two days. The entire process of drying the beans will not exceed 7 days at most.

The third step is to mix the sauce before drying the sauce. This is very important. Be sure to listen to the weather forecast before mixing the sauce. If there is no rainy weather within a week, you can mix the sauce. The weather needs to be fine on the day you mix the sauce. Before mixing the sauce, remove any clumped green mold or black hairs wrapped in the beans and discard them.

One pound of soybeans is mixed with three to four ounces of salt and four to five pounds of watermelon pulp. First wash the peppercorns, star anise, etc. with running water, pick them up, add salt and soak them in a bowl of boiling water. After the water cools down, pour them into the prepared large basin, then pour in the sun-dried beans, mix and soak them. After two hours, add the watermelon pulp and mix.

Cover the mouth of the evenly stirred soybean basin with a layer of pure cotton gauze. Sprinkle some peppercorns on the gauze to avoid attracting mosquitoes.

Put the saucepan covered with gauze in the sun to dry, stir it once in the morning when moving out, and then move it into the room at night to avoid being exposed to rain. After drying for more than ten days, you can prepare it and use it after smelling the aroma of the sauce.