Advice originally from mayoclinic.com/health/legumes/NU00260:
Preparing legumes: soak, then cook
Beans and dried legumes require soaking before cooking. Soaking the beans rehydrates them for more even cooking. Before soaking, pick through the beans, discarding any discolored or shriveled ones or any foreign matter. Depending on how much time you have, choose one of the following soaking methods:
- Slow soak. In a stockpot, cover 1 pound dried beans with 10 cups water. Cover and refrigerate 6 to 8 hours or overnight.
- Hot soak. In a stockpot, bring 10 cups of water to a boil. Add 1 pound dried beans and return to a boil. Remove from the heat, cover tightly and set aside at room temperature for 2 to 3 hours.
- Quick soak. In a stockpot, bring 10 cups of water to a boil. Add 1 pound dried beans and return to a boil. Boil 2 to 3 minutes. Cover and set aside at room temperature for 1 hour.
- Gas-free soak. In a stockpot, place 1 pound of beans in 10 or more cups of boiling water. Boil for 2 to 3 minutes. Then cover and set aside overnight. The next day 75 to 90 percent of the indigestible sugars that cause gas will have dissolved into the soaking water.
After soaking, rinse beans and add to a stockpot. Cover the beans with three times their volume of water. Add herbs or spices as desired. Bring to a boil. Then reduce the heat and simmer gently, uncovered, stirring occasionally, until tender. The cooking time depends on the type of bean, but start checking after 45 minutes. Add more water if the beans become uncovered. Other tips:
- Wait to add salt or acidic ingredients, such as vinegar, tomatoes or juice, near the end of the cooking time, when the beans are just tender. If these ingredients are added too early, they slow the cooking process.
- Beans are done when they can be easily mashed between two fingers or with a fork.
- To freeze cooked beans for later use, immerse them in cold water until cool, then drain well and freeze.
- One pound of dried beans yields about 5 or 6 cups cooked beans. A 15-ounce can of beans equals about 1 1/2 cups cooked beans, drained.