Unless you’re a soap maker, you might not have heard of superfat before! But it’s a great quality to be aware of! We’re going to get a little technical here, but I’ll try to keep it basic!
Superfat, or superfatting, is a component of a soap recipe. It’s the amount of oils that do not react with the lye, leaving them “free” in your soap. During saponification (the chemical reaction to make soap), the lye reacts with the oils and becomes soap. When the lye reacts with 100% of your oils, that would be considered 0% superfat. When you add additional oil above what your lye will react with, that’s the super fat! This excess oil is great for creating a more moisturizing, less stripping bar.
In my soap making, I typically use an 8% super fat. If I wanted to create something like dish soap, I would use 0% or 1%. Soap is still soap, but if you were to use a low to no superfatted soap, you might find your skin feeling a little tight or dry.
We haven’t talked about hot process soap (because I don’t have any experience making it myself) but there is a key difference I want to add with regards to superfat! With cold process, you cannot control which oils are the “excess” oils because it is all mixed together before the reaction takes place. With hot process, the chemical reaction takes place much faster and you are able to add your extra oils at the end while the soap is still fluid - controlling which of your oils will be your super fat. (Any hot process makers, let me know if that’s not quite right, but that’s what I understand.)
And that’s the quick rundown on superfat! Have any more questions? Leave them in the comments!