How long can black beans soak in water before they are rotten?

Black beans can safely soak in water for up to 12 hours without becoming rotten. If soaked for longer, they may start to ferment or develop an off smell, indicating spoilage. It's best to soak them overnight in the refrigerator if you need a longer soaking time, as this helps prevent any undesirable bacterial growth. Always rinse and check for any signs of spoilage before cooking.