Cover beans with cold water by several inches and stir in 1 tablespoon salt and ¼ teaspoon baking soda. Soak at least 12 hours, or overnight.
Once the presoak is done, drain well and rinse with fresh water, and add them to a Dutch oven.
Preheat oven to 250°F (120°C). Pour enough water into the Dutch oven to cover the beans by 2-3 inches. Add 1 teaspoon salt to the pot, plus aromatics (e.g., carrots, onion, rosemary,garlic, sage, or thyme).Bring everything to a gentle simmer on the stovetop.
Cover the Dutch oven, and place in a preheated 250°F (120°C) oven. Begin checking the beans for doneness at the 45-minute mark.
Cook until tender.
Cool and store or use immediately.
Notes
1 pound dried beans yields approximately 6 cups cooked beans.
Cooking times vary significantly based on bean age.
Always boil kidney beans for 10 minutes before slow cooking.
Salt helps season beans throughout and does not make them tough.
For best texture, begin checking for doneness early and continue cooking as needed.