I made a mistake of not boiling my black beans for a veggie chilli before adding other ingredients. They were soaked quickly, for 2 hours after bringing to the boil for 2 mins. I then drained the water, added stock and boiled whilst adding the rest of the ingredients as I peeled and chopped them. I think the salt and acid have inhibited the cooking, so after 4 + hours (with an overnight in between as I gave up on dinner last night) they are still not soft. Are these safe to eat, even though they still have a bit of a nutty bite to them? If not, can I salvage?