Drain the beans in a colander in the sink (whether you used the overnight or the quick soak method).
While the beans are sitting in the colander, rinse out the soup pot very well and return to the stove top.
Set burner on medium and melt the butter in the pot. When the butter is melted, add the pieces of bacon and allow them to cook. (see notes below if you are using a ham bone, ham hock, turkey wing or tail or any other cut of meat for flavoring)
Once the bacon is cooked, add the onion. As the onion begins to soften, add the garlic and let it cook for 1 minute.
Add the cayenne, salt and pepper and immediately add the water and chicken stock concentrate and then immediately add your soaked beans. The amount of the liquid should cover the beans by an inch or two. If it doesn’t add more water until it does.
Stir well and bring the pot up to a simmer (not a full on rolling boil, just a gentle little simmer). If you have a piece of meat to add to your beans (see notes) this is the time to add that.
Cook this way (by simmering) for 1-2 hours. Test your beans to see that they are the softness that you desire. Some people like theirs more firm and others soft. It’s entirely up to you. If you like yours more soft, then cook longer. The longer you cook, the softer they will get.
Add the apple cider vinegar before tasting for salt (see note)
Taste your beans for the level of salt. If they don’t taste quite right, chances are that you haven’t added enough salt. Add salt by the half teaspoonful, stir, wait for a minute or two, stir again and then taste. Keep doing this until they are salted the way you like. Do the same with the pepper.