Legend has it soap was first discovered by women washing clothes along the Tiber River at the bottom of Sapo Hill in Rome. Clothes became cleaner there, with far less effort. What was happening? Animal grease and ashes from sacrificial fires at Sapo Hill mixed with rainwater and ran down the slope as soap. Saponification, the chemical name for the soapmaking reaction, bears the name of that Roman hill.
Water + Caustic + Fat/Oil = Soap
Yes, it really is that simple. All soap consists of the same basic components.
My interest in soap began about 50 years ago, when I couldn’t find a soap to wash diapers that didn’t cause my babies’ bottoms to burn. They couldn’t tolerate the caustic chemicals and perfumes in modern detergents. My grandmother encouraged me to make my own soap. I started with a washing soap of lye and lard because they were available. The hard white soap left flakes on the clothes if you didn’t put the bar in a sock. But my children didn’t have reactions to their clean clothes.
Fat/Oil + Sodium Hydroxide/Potassium Hydroxide + Water = Soap
Soap making is about Balance. It is a Science and an Art.
I began teaching soapmaking in Africa about 12 years ago. At first, my students were intimidated by the idea. But once I told them they had already done this hundreds of times, scooping ashes and scouring greasy pots with them, they were ready to start. The medicinal African black soap is made from the ashes of medicinal plants (potassium hydroxide), since sodium hydroxide (lye) is not readily available.
Many African countries depend on wood fuel for their energy consumption. Dried palm branches, dried banana peels, cocoa pods, kapok tree wood and oak wood (or for brilliant white soap, apple tree wood) make the best lye ashes, but ordinary wood used in cooking fires will do.
Water from a spring or rain shower is called “soft water” because it lacks metallic or acidic chemicals. Soft water is useful for soapmaking, as there are no other chemicals in it which would interfere with the process. “Ordinary” bore, well or river water can be used for making soap, but some of the chemicals in the water may adversely affect the outcome. I once used my bottled drinking water, and everything turned black! It was a good lesson in not trusting water just because it’s bottled.
o make soap, gather ashes in a non-metallic container and add water. If an egg will float on the surface, just below halfway, then the lye water is at the right strength. If the egg will not float, then the lye water could be boiled down to make it stronger. Next, measure the oil and slowly add the caustic solution. Stir until it starts to thicken, then add any oils for scent or function. In African counties, Neem oil is added for mosquito protection.
I have never made the same soap twice in any African village. Something is always different, from the cooking pots to the oils used. My soapmaking time there has been a wonderful adventure of art and science that provides a much-needed product for hygiene, food safety and income in countries that have little options.
Published in the Freshwater Reporter, January 23, 2022, Making soap with ashes – Freshwater Reporter (freshwater-reporter.com).