1. Sieve out the impurities from the mung beans, wash them clean, put them in a basin and soak them in cold water (use warm water in winter, the water volume is 2 times higher than the mung beans) for more than ten hours. When the bean skin falls off when twisted with your hands, take it out, add water and grind it into a thin paste (the finer the grinding, the better). Approximately 2.65 kilograms of thick paste will be produced for every kilogram of mung beans. Then, add 1.5 kilograms of slurry water (that is, the clear water skimmed out when making soy milk and starch the previous time) into the thin paste, and gradually add no less than 12 kilograms of cold water to filter. Approximately 17 kilograms of powder slurry and 2 kilograms of bean dregs can be filtered out. ,

2. Pour the slurry into a large vat and allow it to settle overnight. The white starch settles to the bottom of the tank, with a layer of gray-brown black powder on top. The next layer is gray-green, thicker raw bean juice, and the top layer is foam and slurry. Skim off the foam and slurry water, and scoop out the raw bean juice (about 8 kilograms of raw bean juice can be obtained, as well as about 500 grams of starch and a small amount of black powder). It needs to be allowed to settle once before cooking, and it will settle for six hours in summer. It settles overnight in winter. After settling, skim off the slurry on top.

3. Put a little cold water in the pot, bring it to a boil over high heat, then pour in the raw bean juice. When the bean juice gradually swells and overflows out of the pot, immediately switch to low heat to keep it warm (do not use high heat at this time) , otherwise it will be cooked into Ma Tofu), eat as you like, and serve with spicy pickles