1. Place the black beans in a saucepan and cook over medium heat until the skin bursts open, then cook over slow heat for about 10 minutes. Put the cooked black beans into a tightly sealed bottle and add the aged vinegar, about 1/3 and 2/3 of the volume of the two. When cool, seal the lid and soak for about two hours until the black beans have absorbed the vinegar and swelled up, then it is ready to be eaten. It takes about 1 day.

This method has the advantage of being quick to make and the disadvantage that a component called unsaturated fatty acids, which can play a role in inhibiting cholesterol, are said to be destroyed when black beans are heated.

2. The appropriate amount of raw black beans after washing and drying, soaked in 8 degrees of acid old vinegar, sealed in a cool place to soak for about two weeks, this method of time and effect are better, recommended.

3. Wash and dry the appropriate amount of raw black beans, soaked in 8 degrees of acid old vinegar, sealed in a cool place soaked half a year to a year. This method is delicious to eat, neither raw bean flavor, and easy to digest, eat more will not cause diarrhea. But the time is too long.

Black beans in vinegar can be eaten on the same day after they are made, and can be kept in the refrigerator for half a year, so you can make some more each time. Black beans itself has a natural sweet flavor, vinegar soaked black beans taste mellow, more delicious. If you don't like the sour flavor of vinegar, you can also add a small amount of honey.