You hear the term a lot when talking about soap because, well, it is the process by which soap is made! Part of the allure of soap making is that it is equal parts creativity and science. The saponification is the science part. So, what is it anyway? Glad you asked!
But first, let’s back up. You can’t talk about soap – true soap, without talking about lye. And, many times, when you mention lye, people get a little edgy. That’s because lye is serious business. Lye is a caustic chemical that historically has been derived by leeching ashes, however, there is a more modern process called “membrane cell chloralkali process” that produces a more stable product.
Saponification happens when triglycerides (oils) react with either sodium or potassium hydroxides (lye).
By the time you get a true bar of soap (not a beauty bar!), all of that lye has been eaten up by the saponification process, and all that is left is the good, nourishing oils for your skin. So, no more lye is left in the bar of soap, so you do not have to worry about it hurting your skin – it is only needed to transform the oils and butters into what you use!
Let me know if you have any questions, I would be happy to talk to you more about it!