1, 12 hours or more: According to Sohu. Com, the dried kidney bean skin I bought is very hard. If possible, kidney beans can be soaked in cold water one night in advance and washed and boiled the next day. If you stew the soup with dried kidney beans that have been soaked all night, it is easy to stew.

2, 4 hours or so: If hot water is used, the water temperature is controlled at about 80 degrees, which can greatly shorten the brewing time. High temperature can quickly soften the surface of dried kidney beans, and it is also very easy to boil after cooking.