How to cook Black Beans. Soak 2 cups of dry black beans overnight, then rinse. Place in the Instant Pot with enough water to cover the beans. Pressure-cook on the bean setting for 27 minutes. Allow pressure to release naturally for at least 20 minutes; then you can release the pressure manually the rest of the way. Remove the beans from the Instant Pot before starting the saute step with the onions. As long as you will be using the IP to slow-cook your soup, you don't need to rinse off the bean starch before the next step. The beans will only slightly tenderize more in the slow-cooking of the soup, but won't get mushy.