What does cowpea look like? Green heart? Did you see that Yangshengtang said that you need to use cowpea to soak black beans in vinegar? There are many kinds of black beans on the market. Which one is it? There are two kinds of black beans in the general market, one is a round yellow core like soybean, and the other is a small, somewhat flat, somewhat kidney-shaped green core. It doesn't make much difference if you eat it, but when you use Chinese medicine, you choose a small kidney shape. The price of green heart black beans is higher than that of yellow heart black beans. Just bite a few when you buy it.