Soapmaking - how hard can it be, right? Mix together some oils and lye and water and pour it in a mold. No biggie.
Well - here it is in scientific formula terms:
The scientific term for oils and lye becoming soap is saponification. This is a chemical reaction that creates a lot of heat (known as exothermic) when the fats in the oils react to the lye (sodium hydroxide), which is a base. During this reaction, the triglycerides in the fats reach with the lye and are converted to sodium salts of long-chain fatty acids (soap) with a byproduct of glycerine. This process usually takes 24-48 hours, depending on what type of oils are used.
Here at Zarko Hill, we utilize the "cold process" method of soapmaking - we mix the oils and lye and pour into long molds and allow the mixture to do its thing, then unmold the entire loaf and cut it into individual bars that are left to cure for a minimum of four weeks. Curing allows the excess moisture in the soap to escape, leaving a more mild and harder bar of soap.
While the process seems simple enough the science behind it is quite exact. Measurements have to be accurate or you could actually end up with soap that is literally dangerous to use with too much lye, or a soap that's not hard with way too much unsaponified oil. Thankfully, there are lye calculators that do the hard work for you since each oil/fat has a different "SAP Value" or the amount of lye it takes to turn it into soap.
Handmade soap - the perfect intersection of science and art!