Unless you're a soaper, you may not hear or use the term "super fat" often. Or maybe you do. Since super fat doesn't only have to do with making soap. But thats what we're talking about here today!
What is super fat?
When it comes to making soap, super fat is basically the amount of oil that is left over in a soap that remains after saponification. Soapers tend to include a certain % of Superfat in their formula ranging anywhere from 1% - 20% sometimes, even more. This allows for some oil to remain in the soap that's not saponified or bound to lye. This means more moisture in the soap. At Elosa, we soap anywhere with a superset of 8% - 12% depending on the soap. Although every soap has the same oil base formula, the additives and water content alter. Some of our soaps are made with milks, yogurts and some with tea's, resulting in different ingredients.
Interesting Fact: Every oil requires a different amount of lye to be saponified and turn into soap. This is why a soap calculator is extremely crucial for soapers. Even swapping out one oil for another in the same amounts, requires your formula to be run through the calculator again.
Why Super Fat?
Well, soaps are naturally alkaline. Like mentioned before, we super fat to add moisture and mildness. If every last drop of oil was bounded to lye, there's nothing left over to moisturize our skin. It'll cleanse our skin so deeply, it'll end up stripping it if there's no added moisture there. Super fating helps with this and luckily, majority of handmade bars are super fatted.
Most of all, soapers super fat to ensure every last bit of lye has been saponified with the oils, as unsaponified lye can be quite harsh to the skin. A soap with unsaponified lye can be caustic. It is also very evident of a caustic soap bar, when you go to use the bar and your skin starts to become excessively itchy, dry or irritated.
Another interesting fact: When lye and oil combine and start turning into soap, glycerine is also produced. Glycerine is a humectant, which attracts moisture to the skin and forms a protective barrier to prevent your skin losing moisture.