What Causes Soap to Dissolve?

Commercially made soaps dissolve because of the chemicals that are used to make the soap and because of the excess moisture and water content that is left in them. Good homemade soaps are cured for a least a month to give you a longer lasting bar, because not curing them, or allowing them to dry the excess moisture out of them before being used, is what causes soap to dissolve on your sink even when you are not using it.