Put several rectangular plastic bottles filled with hot water at 50℃ into a clean foam box, and put foam lunch boxes inoculated with Bacillus natto on the bottles. The ideal temperature in the box is 42℃. If the temperature in the box drops to 38℃, replace the bottle with 50℃ hot water. Repeatedly changing the hot water in the bottle, and fermenting for 14-36 hours, a white film was produced on the surface of soybean, and the soybean became rotten after silk sticking. If there is no foam box, you can also use a large cardboard box, wrapped with a quilt and an electric mattress, or insert a 45℃ light bulb in the box to keep the temperature inside the box constant. Pay attention to more exposure to air.

After ripening, fermented at a constant temperature of 38-42℃ 14-36 hours, and then stored in the refrigerator at low temperature for several hours, the appearance and taste of the finished stinky beans will be better. Therefore, it is suggested that stinky beans should be stored in the refrigerator for several hours before eating or long-term storage.

The key is to keep the temperature at 38-42℃. (2) Bean bacteria should be inoculated into hot soybeans (the temperature is preferably 38-45℃, and the bean bacteria will be killed if the temperature is too high).