Ma tofu is the leftover of mung bean vermicelli and starch, but the fermented bean juice is boiled with fire and filtered with cloth, and the remaining bean dregs are Ma tofu.

Ma tofu has the nutritional value of clearing away heat and toxic materials, preventing cardiovascular diseases, beautifying and resisting aging.

Ma tofu, like bean juice, is the favorite food of old Beijingers. Ma tofu has a special sour taste due to fermentation. Old Beijingers like to eat horse tofu, just like drinking bean juice.