Making soap is like following a recipe for pastry and turning it into a pie. Soap is made up of three basic ingredients: water, lye, and fats (oils). When a lye-and-water solution is mixed with fats, a reaction takes place between the hydrogen, oxygen, sodium, and fatty acid molecules. This is called saponification, and the end result is a substance that is made up of five parts soap and one part glycerin. Glycerin – a rich emollient prized for its ability to soften the skin is retained in handmade soap but in commercial soap it is extracted, leaving behind the hard, drying bars of soap we purchase in stores and supermarkets.