Seven to nine hours. Oysters are dry, and they taste better when soaked. Because there is sand in the oyster, it has a fishy smell and is resistant to foaming, so it takes a long time, 7 ~ 9 hours. Soak it soft and wash it clean to get rid of the odor. Not soaking your hair will affect your taste. Don't be afraid of losing nutrients in the water. Soak your hair, wash it several times, and remove the broken shells and sand. Oyster black beans, also known as "dried oysters", are dried seafood and oyster (also known as oysters) meat.