Why does my soap have 'super-fat'??

Heard the term 'super fat' in regards to soap? Wondering why on earth you would want your soap to be super fat? Should it go on a diet? I'll explain....

Soap is made from fats and oils. Each fat or oil has a SAP value (or in other words, a number given at which point the oil or fat molecules will become soap molecules when introduced to the alkali). For example, coconut oil has a SAP of 0.257, and olive oil has a SAP of 0.190. It is with these numbers that I can use a lye calculator to figure out how much lye is needed to turn a specific recipe of oils into a wonderful bar of soap! Still following? :)

Now, superfat is fat or oil that is left over after the lye is added. Essentially, I would add less lye then that amount of oils required. Why would super-fatting be a good technique, then? For one thing, it allows for a cushion to guard against dangerous lye-heavy soap. For another thing, it means that there is oil left in the soap that isn't soap, and is therefore left to better condition your skin. Done at the right percentage, it is a wonderful thing for a handmade soap.

Most handmade soaps have a superfat of 5%. This means that 5% of the oils in the formula are not saponified. I go with a tad higher percentage of superfat on most of my soaps, with the exception of the spa sticks, which are superfatted at a very high 20% (to counter act the very high cleansing properties of the coconut oil they are made with).

So, go ahead, let your soap be super fat. Your skin will thank you.