1, material: mung bean 2000g, a pulverizer (enough soymilk machine), a pot for bean juice (preferably a porcelain jar with a cover), a piece of bean cloth for filtration, and appropriate amount of water.

2. Wash mung beans first and soak them in cold water for about 20 hours.

3. Put the soaked mung beans into a pulverizer, and add water when pulverizing, with the ratio of 1 5.

4. Filter the ground soybean milk with bean cloth and put it in a container for fermentation.

5. Just wait until it is sour (the fermentation time depends on the weather temperature).

6. Put the fermented bean juice into the pot, don't boil it with a small fire, turn off the fire, and thus make a sour bean juice.