(1) Soaking: firstly, wash the soybeans with clear water to remove impurities in the floating soil, then take them out and put them in a jar, and soak them in clear water for 3-4 hours.

(2) Steaming at normal pressure for 3-4 hours, without hardening, and kneading into cakes by hand.

(3) The traditional method of steaming beans to make koji makes natural Aspergillus flavus grow and reproduce naturally. Mix steamed soybeans and flour evenly, spread them on a reed mat with a thickness of about 3 cm, and keep the room temperature at 28 ~ 30℃. After 1 day, the soybean koji becomes a block, which is turned for the first time 1 time, and then turned for the second time in about 6 hours. Keep the temperature for about 3 days, and when all soybean koji is slightly Huang Shi, it will become koji. After koji-making, it is dried in the sun and fermented: the watermelon juice is evenly mixed with salt, Jiang Mo, dried tangerine peel and fennel, then mixed with dried bean yolk, put into a jar, dried in the sun and soaked, and sealed for 40-50 days when the salt is completely dissolved and the fermented bean is suitable for thin consistency, thus obtaining the finished watermelon fermented bean.

The finished product is light brown sauce, full of beans, covered with sauce film, and the liquid is pasty. It has mellow smell, strong ester and sauce flavor, soft and delicious taste, soft and refreshing, and a long and sweet aftertaste.