Source: Tammy
Dry Bean Preparation
The night before cooking, remove any debris from beans. Rinse them, then place them in a 4-quart Dutch oven or pot of similar size. Add 6 cups water, 1 teaspoon salt and the baking soda. Cover and set aside in a cool place for 8 to 12 hours.
The soaked beans can be cooked in the same soaking water as long as you had previous rinsed the dry beans well.