Hardwood ash
Wood ash plays an integral role in traditional cold process soap making. When wood ash from hardwoods is combined with water, lye, or potassium hydroxide, is created. Lye is a necessary ingredient in making soap. Lye, a strong alkali, when mixed with animal fats or vegetable oils, causes a chemical reaction called "saponification." Saponification produces two materials: soap and glycerine.
History
Roman Ruins
According to Roman legend, soap was created by accident not far from Rome, on Mount Sapo. A temple sat atop Mount Sapo and was used for burning animal sacrifices as offerings to the gods. The river Tiber flowed below Mount Sapo and was favored by women as a place to wash clothes. The women discovered that after a rainstorm their clothes were softer and easier to clean. It did not take them long to find a white substance stuck to the rocks on the hill that the rainwater had flowed down to meet the river. The wood ashes from the sacrificial altar, combined with the rainwater and animal fat, had saponified and flowed down the hill to the river. In short, it had made soap. The word "saponify" comes from Mount Sapo.
Interesting fact: When the ruins of Pompeii were uncovered, a soap factory was found, still stocked with bars of soap.
Evolution of Soap
Soap making was continually refined through the ages, with some cultures adding salt to harden bars of soap and others even using seaweed ash along with wood ash. By the time the first colonists came to America, soap making was an important and necessary part of housekeeping. It was a lengthy process; therefore it was done a few times a year to make a large quantity. Soap had to be allowed time to "cure" or harden. If the soap was used before it was fully cured, it could be too caustic, or the bars could break down quickly.
Commercial Soap Manufacturing
By the 1700s, enterprising soap makers were called "soap chandlers." They collected tallow, or animal fat, from homeowners and used it to make soap, which they would in turn sell back to the homeowners.
In 1800s New York, soap began to be manufactured commercially in large factories by William Colgate. In 1837, William Proctor and James Gamble began their chemical empire with soap making in Cincinnati. We know these companies now as Colgate, and Proctor and Gamble. The use of sodium hydroxide (caustic soda, which is also called lye) was favored as an alkali rather than potassium hydroxide in large manufacturing operations. Another major difference in small vs. large operations: small soap manufacturers (like chandlers) left the glycerine in the soap, while large operations separated the glycerine from the final product and sold it in other forms, thus creating at least two products from the saponification process.
Producing Wood Ash Lye
An egg and a feather can be used to measure lye strength.
So how exactly is wood ash lye made? The process is still virtually unchanged. First, a large barrel with holes punched through the bottom is placed over a large slab or pan to collect the lye water runoff. The bottom of the barrel is lined with straw. The barrel is partially filled with hardwood ash. Then water, preferably rainwater, is poured slowly over the ashes and allowed to leach through and finally run out the bottom of the barrel into a holding container. Repeated leaching of the lye water through the ashes will strengthen the lye. Traditionally, two methods are used to test the strength of the lye. The first is to drop a feather into the lye water. If it dissolves, the lye is ready. The second and more reliable method uses a raw egg still in its shell. The egg is floated in the lye water. If it floats just at the surface with a quarter-sized area showing above the surface, the lye is ready. If it floats below that, the lye is too weak. Higher than that, the lye is too strong and needs to be diluted with more water.
Making Soap with Wood Ash Lye
Lye water is placed in a stainless steel pot and allowed to cool. The chemical reaction created when making lye water makes the water very hot. It must be cooled before use. Next, the fats or oils are added slowly to the lye water, taking care that the fat is the same temperature as the lye water. The mixture must be stirred continuously until it begins to "trace" or thicken, signifying the saponification of the ingredients. At this point any additives, such as herbs or fragrances, are added. Once the soap mixture is well blended, a soap maker pours the mixture into molds and allow the soap to harden. Soap made by this process must be cured for two to eight weeks.
Tags: Mount Sapo, bars soap, bottom barrel, chemical reaction, combined with, flowed down