Although no one truly knows when soap originated, it has been used for thousands of years. According to Roman legend, soap was named after the mountain Mount Sapo, where animal sacrifices took place. After a sacrifice to the gods, the fat and animal ash would be washed into the river under the temple. Roman women commonly washed their clothes downstream and found that if they washed their clothes in certain parts of the river, their clothes would come out much cleaner than in other parts. Thus, the first use of soap!
Now how was soap created in the river using just ashes and animal fat? The creation of soap includes two main parts, sodium hydroxide or potassium hydroxide (lye) and any kind of fat or oil. Sodium hydroxide, also called caustic soda, reacts with triglycerides in fat and oil and turns them into soap and glycerin. You can take pretty much any kind of oil or fat and turn it into soap – coconut oil, shea butter, olive oil, even bacon grease if you are so inclined! This is how all soap is made, even soaps that can be purchased in brick form to be melted down and poured into a mold, such as the ones that Lush uses. These melt and pour soaps are made primarily made from glycerin, which is harsher on the skin than nut oils commonly used for cold process soap such as shea butter, almond oil, avocado oil, etc.
As for the process of soapmaking, I personally use a technique called “cold process.” First the oils are melted down and heated to about 125 degrees, and a lye water solution is mixed separately. When lye is added to water, it causes a chemical reaction that causes it to become extremely hot (around 170 degrees or more.) I then wait for the lye to cool to the same temp as the oils, and then the two are mixed together with a hand blender. As the two are mixed, the saponification process starts and the mixture slowly thickens. Fragrances and colors can be added at this point, and then the soap is poured into a mold and left to harden overnight. The process sounds easy enough, but there are quite a few pitfalls! Even if the exact same process and materials are used, sometimes there can be some unexpected variations in the soap.
A common misconception of handmade soap is that lye still exists in soap after it undertakes the chemical process of saponification. After approximately 48 hours, all of the lye has reacted with the fat and it is no longer present. Soap is then left to cure for as little as a few weeks, or as long as a year. A true castile soap is made from 100% olive oil and can take a year or more to cure. As a general rule, if the oils that are being used to make soap are liquid at room temperature, it will take much longer for the soap to harden and cure than if you use oils that are solid at room temperature (such as Coconut Oil). Each oil has different properties as well, adding different elements to the final bar. There are so many different kinds of oils that it is not uncommon for a soaper to spend years perfecting their recipes.
Overall, soapmaking is a wonderfully challenging and inspirational process, one that comes with many benefits. Not only does natural soap benefit skin, but talk to any soapmaker and I’m sure they’ll tell you it helps with their mental health as well!
Till next time,