Rinse the beans and pick out any stones or shriveled beans. Drain the beans and add to a 3- to 7-qt/3.5- to 6.5-L slow cooker. Add the onion and garlic (if using), the salt, the bay leaf, and enough cold water to cover the beans by 2 in [5 cm], or about 8 cups [2 L]). Cover the cooker and cook on low heat until the beans are tender, 5 to 9 hours, depending on the age of