1. Tofu production: Soak soybeans in water, wash them with clear water, replace them with 20-25 kilograms of clear water, grind them into a thin paste with a stone mill, add warm water of the same amount to the thin paste, mix them evenly, put them into a cloth bag, squeeze out the slurry, mix them with boiling water in bean dregs, and then squeeze them. When the bean dregs do not touch hands continuously and the soybean milk has been squeezed out, skim off the foam and add the slurry. If the dripping water is not mixed with the pulp, it will turn into tofu brain in about 20 minutes. Scoop the bean curd into a wooden box, cover it with wooden boards, press on heavy stones, and press off the water, and it becomes bean curd. To make stinky tofu, if tofu is special, it will be harder than tofu we usually eat, but softer than dried tofu.

2. Fermentation: Put the prepared tofu on the shelf piece by piece. A wooden shelf can hold more than a dozen layers of tofu, and the middle can be ventilated, coated with salt and sprinkled with mold (the bacteria are dissolved in water and the fingers are stained on the tofu). Put it in a ventilated place without direct sunlight for two to three days. In summer, the temperature in the house can go up and down 32 degrees, and tofu will grow an inch long white hair, which is mold.

3. Treatment after fermentation: put the soap alum into a bucket, pour boiling water and stir with a stick, soak it in tofu for about 2 hours, then take out the tofu and cool it. Then soak tofu in brine for about 3-5 hours in spring and autumn, 2 hours in summer and 6- 10 hour in winter. Take it out after soaking, wash it with cold water and drain it. (preparation method of bittern: based on 2.5kg douchi, it is necessary to add 15kg water to boil, filter, add 1500g alkali to the juice, soak for about half a month, stir 1 time every day, and obtain bittern after fermentation. )

4. Further processing according to the tastes and characteristics of different regions.