How to Make Homemade Soap in 6 Easy Steps- making natural soap at home ,Jan 16, 2020·Soap, by definition, is fat or oil mixed with an alkali. The oil is from an animal or plant, while the alkali is a chemical called lye. In bar soapmaking, the lye is sodium hydroxide.How to Make Soap from ScratchJan 16, 2020·Soap, by definition, is fat or oil mixed with an alkali. The oil is from an animal or plant, while the alkali is a chemical called lye. In bar soapmaking, the lye is sodium hydroxide.