What is Saponification?

Saponification in Soap Making

Definition: Saponification is an exothermic (gives off heat) chemical reaction that occurs when fats or oils (fatty acids) come into contact with lye (a base.) Saponification literally means "turning into soap" from the root word, "sapo", which is Latin for soap. The by-products of the saponification reaction are glycerin and soap.

Oils + lye (dispersed into water) = soap + glycerin

Oils and fats each have what is called a “saponification value”, which is the amount of lye needed to completely neutralize them into soap with no lye left over. Each oil has a different value, which is why it’s important to always run your recipes through a lye calculator. We recommend the one on the Majestic Mountain Sage website.
Once oils have been saponified with lye (sodium hydroxide) the lye is no longer available. This means that it is basically "gone"! So, if you are worried about it, don't be. The saponification process has altered the composition of the lye.