There are a few reasons on why your beans can be hard: 1) Stale/Old: Even dried beans require "freshness" to be tender and flavorful. Dried beans that have been stored for more than a year can remain hard and chewy no matter how long they are cooked. 2) Liquid Quantity: While cooking, beans should always be immersed in liquid. They will not cook evenly if there is insufficient liquid. 3) Acidic Ingredients: Cooking dried beans with acidic ingredients such as tomatoes, lemon, vinegar or wine can prevent them from becoming tender. 4) Hard Water: If your tap water is extremely hard, the minerals in the water can prevent the beans from softening. Cook them in filtered or bottle water if possible.