What is Superfat in Soap? What About Trace?

superfat in soap

Superfatting and trace. You hear the terms all the time in soapmaking. They’re both important to the process and they’re both the subjects of questions we hear frequently.

Seen individually, they’re completely different. One is rooted in numbers – percentages and measured amounts – while the other is highly subjective. One can be illustrated in a numerical grid and the other you really need to see to understand. Together they represent the essence of soapmaking, the yin and yang. Some aspects of soapmaking are pure science and math. Others are intuition and experience.

All About the Numbers


Superfatting is a simple concept that can get complicated quickly, depending on the saponification values of the oils you’re using. According to the Natural Soap Directory, superfatting is defined as a practice that involves adding an excess of oils/fats to the soap batch beyond those calculated to completely saponify with the lye.

For every soap recipe, there’s a precise amount of lye to use to ensure the fatty acids and lye have completely bonded and been transformed into soap. That’s the 0% superfat calculation. Most soapmakers, Botanie included, use more oil than can be transformed by the lye. Once you go beyond the 0% level, how far you go is a personal choice, so on our website we give calculations for superfatting levels of 4%-10%. Superfatting ensures that all lye has been consumed and it gives soap increased moisturizing and emollient qualities.

All About the Look and Feel

We keep reading that trace is the most misunderstood concept in soapmaking. If that’s true, much of it has to do with it being a difficult concept to put into words and a much easier one to illustrate visually. In that regard, videos are a boon to soapmaking.

Here’s how the Natural Soap Directory defines trace: the moment when soap batter thickens and becomes viscous. Trace is determined when a spoonful of soap batter dribbled back into the soap pot leaves a ‘trace’ and remains visible on the surface. Likewise, trace may be determined when a spoon moved through the soap batter leaves a ‘trace’ or distinguishable trail on the surface of the soap batter. That’s about as clear as trace explanations get.

Not Really Ominous at All

Some soapmakers call trace “the point of no return,” which sounds ominous, when what it really means is that saponification has progressed to the point where separation will no longer occur. There are plenty of images (if you Google “trace” and then choose images) that illustrate quite well what trace is and how to recognize it. There really isn’t a substitute for videos, though. Here are two that do what single images can’t. They show the ongoing testing done while mixing to determine trace. And they show what trace isn’t, as well as what it is.

The first video has no voice-over. Instead, it uses text over the video to explain its points. It also has a disco soundtrack that won’t be everyone’s cup of tea. Turning down the volume doesn’t lose any of the content. Make sure to watch the beginning to understand the testing process and what trace isn’t. If you want to skip ahead after that to see the moment trace happens, start watching again at 5:25.

The second video introduces the concept of light trace, or early trace, compared to traditional trace, which is what we’ve been describing so far. Because of the efficiency of modern mixers, the video suggests, the point at which soap is sufficiently mixed is reached earlier now than it did in the past. Like much of science, soapmaking takes actual experimentation to perfect. The videos can help get you to the point where you recognize trace when you see it, and they can get you there more quickly and with more assurance.

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