Superfatting - What is it?

Superfatting is a soapmaking technique to make soaps gentler and more conditioning - and here's how!

In soap making, lye is dissolved into water and added to melted oils. Although "lye" can refer to various alkaline chemicals, it specifically means sodium hydroxide (NaOH) in soap making. This new mixture of lye, water, and oils is put into a mold and left to set and cure into a hard bar of soap. While the water slowly evaporates out of the soap, the lye reacts with the oils to saponify them - to turn them into soap.

Lye is a caustic substance and can be harmful when used improperly. That’s why, when formulating a soap recipe, many soap makers (including me!) will use a lye calculator to make sure there is not too much lye in the soap recipe. If too much lye is used, there will be lye left in the final product that will cause burns to the soap user’s hands. If too little lye is used, there will be oils left in the final product that haven’t been turned to soap.

However, leftover oils aren’t always a bad thing!

Most soap makers intentionally leave ‘extra’ or unsaponified oils in their soap recipe, which is superfatting the soap. The percentage of unsaponified oils in a recipe is the superfat. The superfat is beneficial to the soap and the soap user for two reasons:

1) It eliminates the possibility that there could be some unreacted lye in the soap, making certain the soap is safe, cleansing, and nourishing,

And 2) It makes the soap milder, gentler, and extra conditioning!

5% is a standard superfat for most soap recipes. While soaps can be made with any percentage of superfat (0%-100%) , effective ranges are generally between 2% and 8%.

Soaps with higher superfat percentages will be milder, more conditioning than cleansing. Soaps with a lower superfat will have a better lather and be more cleansing.

The oils used in a soap recipe, and therefore used for the superfat, give the soap different properties! You can look up the properties of a given oil to see how it will affect your skin, but I’ve listed general properties of the main oils in my soaps here.

Shea Butter - Shea Butter is moisturizing and nourishing, containing both vitamin E and vitamin A.

Coconut Oil - Coconut oil is very cleansing, and it can be hydrating for dry skin.

Tallow - Tallow really nourishing to the skin! Tallow is similar in formation to our own sebum, so it soaks well into skin and gives lots of vitamins and minerals.

Kokum Butter - Kokum butter is moisturizing and can help soothe skin.

Olive Oil - Olive oil has many benefits, including being moisturizing and gently cleansing.

Castor Oil - Castor oil is used in small percentages in soap recipes, not enough to have a large effect on the superfat. Castor oil is conditioning and stabilizes the soap lather.

I use a standard 5% superfat in many of my recipes, but soaps with certain purposes need higher or lower superfat percentages. I identify oils used in the recipe on the listing for each soap, so you can know what oils you’re getting in your superfat, and exactly what kind of soap you’re getting!

And that's superfatting!