2. Bean juice is the leftover of making mung bean starch or vermicelli. Soak mung beans until they can be twisted and peeled, take them out, add water and grind them into fine pulp, and pour them into vats for fermentation. What sinks in the bottom of the vat is starch, and what floats on it is bean juice. Because it is fermented, it is difficult to swallow with the smell of swill. Drink it twice through your nose, and it will feel different.
Bean juice is a unique food in Beijing. Because of the strong rancid smell, it is difficult for ordinary people to adapt. Mr. Wang Zengqi also said: "This thing is fermented by mung beans and has a sour taste. People who don't like drinking are said to be like swill and sour. The drinker said: nothing else can have this taste-sour! This is just like stinky tofu. Some people love it, and some people don't. "