Superfatting In Soap Making:

Some of the more common terms used in homemade soap making are water discountingtrace, and gel phase. However, the term superfatting can also be a real head scratcher for first-time soapers. 
Heck, it left us scratching our heads as well, when we first starting making soap, a few years back. So what is superfatting in soap making?


what is superfatting in cold process soap making


Let’s Start with the “BIG” Picture!

In an effort to help explain superfatting, let’s break it down in terms of what exactly happens as soap is being made. Once your oils and/or butters are mixed together with your lye solution, the saponification process begins. Meaning, that the chemical process of your lye and your oils and/or butters has begun.
Now, each oil has it’s own saponification value (if you remember from our blog on SAP value), this is the amount of lye it takes to turn 1gram of oil into 1 gram of soap. 

Right, so we have this lye solution (most of the time lye + water) poured into our oils. Believe it or not there is a specific mathematical formula behind finding out how much lye is needed to turn a specific amount, of a specific oil, into soap.

Now, the chemical reactions start. Lye molecules begin pairing up with molecules of the oils you chose, your mixture starts heating up, and the process has begun to form a new substance….Soap!


Related Article: Base Oils and Their Fatty Acid Properties In The Soap Making Process


Where Does The Term ‘Superfatting’ Come into Play?

Theoretically you’re probably thinking, “okay, we are going to need just enough oil(s) and just enough lye to cancel each other out”? This would be known as “zero superfat”

The answer to that is yes and no. 

We obviously want no lye left over once the soap is made. However, if you had NO OILS left, your soap would (most likely) not be very moisturizing in the finished soap.

With that being said, superfatting is the extra amount of oils/fats that are calculated into a recipe. The extra oils/fats lend to moisturizing properties (also known as “emollient” properties) and make for a much more desirable bar of soap. 

Normal Ranges of Superfatting:

Normally you will see the averages between 5% – 7%. That means 5-7% extra oils/fats in the recipe once your bar of soap is made. 


Warning! About Superfatting!



Be careful not to get to heavy handed with the “superfatting” or extra oils. To much can lend itself to a undesirable soft bar of soap.

Oils themselves can also spoil. If you have too much extra oil, there may be a greater chance your soap falls victim to the “dreaded orange spots” or DOA. 

“1” exception to the normal rules of thumbs in superfatting is with 100% coconut oil soaps. If you are making a 100% coconut oil soap, you’ll want to superfat around 20%. Coconut oil is known for it’s cleaning properties, but at 100% would be harsh and strip away oils from your skin. Thus, leaving you very dry and not very happy : (


Final Thoughts!

Most lye calculators, calculate the superfatting aspect automatically. You plug in 5%, 6% or 7% and out shoots the excess oils you’ll need to make that happen.

Again, soap is a science, but it also should be based off of what you are doing with the soap. What is the goal of “the next” bar of soap you create? What end properties do you want it to have?

Of course there is always the trial and error game we “soapers” play. Soap(s) don’t always turn out according to plan, that’s okay, it’s how you learn! We hope you enjoyed this post on superfatting in soap making!