Soap Making Trace: Know Everything About It

Have you ever wondered what trace means in soap making recipes? What is it? Why is it important?

Soap making trace refers to the point in the soap making process where the oils and lye have emulsified properly, allowing for the mixture to harden and cure, turning into soap. Identifying trace involves observing changes in the mixture’s consistency, and it is essential to create high-quality soap. It’s a milestone in cold and hot process, meaning that you should add your fragrances and antioxidant (the so called “After Trace” ingredients) and pour your mixture into the molds.

Find everything you want to know about trace in this post. Just keep reading.

What is Soap Making Trace?

Soap making trace is a term used to describe the point in the soap making process where the soap mixture thickens enough to leave a visible trail or “trace” when it’s stirred or dripped back into the pot. This indicates that the oils and lye have emulsified and the soap making process is progressing as it should. The thickness of the trace can vary from light to heavy, and each stage of trace has its own characteristics and benefits.

What are the Different Stages of Trace in Soap Making?

There are different stages of trace in soap making, including light trace, medium trace, and heavy trace.

  • Light trace is the first stage, where the mixture starts to thicken and become opaque. At this stage, the soap mixture is still pourable and can be easily poured into molds.
  • Medium trace is the second stage, where the mixture becomes thicker and starts to leave a faint trace when stirred. At this stage, the soap mixture is thicker and may require a little more effort to pour into molds.
  • Finally, heavy trace is the last stage, where the mixture is very thick and leaves a distinct trail when stirred. At this stage, the soap mixture is very difficult to pour and may require spooning or piping into molds.

Light trace is the initial stage of trace, where the mixture is still relatively fluid and has just begun to thicken. This is often the stage where fragrances, colors, and other additives are added to the soap. At this point, the soap mixture is still pourable, and it’s easy to work with. This is great for complicated swirls, where you need your soap to be very fluid.

Reaching light trace – image

Heavy trace, on the other hand, is the final stage of trace, where the soap mixture has thickened to a consistency similar to a paste. The soap will hold its shape when dripped back into the pot, and it’s no longer pourable. This stage is ideal for creating textures, shapes, or other decorative effects in the soap. The characteristics and benefits of each stage of trace can vary depending on the recipe, but generally, light trace is good for adding additives and visual swirls, while heavy trace is ideal for creating decorative effects.

Heavy trace – image

What Causes Trace in Soap Making?

Soap making trace is caused by the emulsification of the oils and lye in the soap mixture, also called saponification. Saponification occurs once the oil and lye molecules create new soap molecules, also known as fatty acid salts.

As the mixture is stirred, the oils and lye combine into soap salts and start to thicken, resulting in trace. The speed at which trace occurs can vary depending on the type and amount of ingredients used, the method of mixing and temperatures. Using a stick blender or immersion blender will definitely speed up the process, while stirring by hand will take … too long!

How Do You Identify Trace in Soap Making?

You will only learn how to identify trace with experience. There are a few ways to identify it:

  • One method is to use a spoon or spatula to drip a small amount of the soap mixture back into the pot. If the mixture leaves a visible trail or indentation, it has reached trace.
  • Another method is to use a whisk or immersion blender to stir the soap mixture. When the mixture starts to thicken and hold its shape, it has reached trace.

What you are able to see with the “markings” in your soap batter is called medium trace: the soap is still fliud but not totally liquid any more. It’s like liquid pudding. This is what you will be able to identify as a beginner.

reaching trace
Trace “markings”

I was lucky to start my very first soap making experience with a 100% olive oil soap. I reached a heavy trace before molding the soap – yes, I did use the immersion blender A LOT – and I was able to see all the chemical transformation from lye water and oils to soap, observing all the trace stages. Another advantage is that you also have time to hesitate and take your time to understand what to do next, something you really can’t afford to do with other recipes. I highly recommend to start making soap at home with a 100% olive oil soap. If you want to see that and other beginner recipes check out this link.

It’s very important to keep an eye on the soap mixture during the soap making process to ensure you don’t miss the trace stage.

What If I Skip Trace Somehow?

You won’t. Once oils and lye water are mixed, with some mechanical action (immersion blender) trace will eventually happen. The mixture will go through the phases in the image below:

Top left: lye water poured over oils, no mixing; Top right: mixing soap still not emulsified (floating oils); Bottom left: light trace, no floating oils; Bottom right: Medium trace with “markings”

I know it sounds difficult, but it’s not that much once you make soap by yourself a couple of times. If you’re very distracted, at most, you will reach heavy trace, but then you will notice your soap batter changing: it’s no longer liquid. The only way to skip trace is with a false trace.

What Is False Trace?

That’s a good question! False trace is a common issue in soap making, where the soap mixture appears to have thickened and reached trace, but in reality, it hasn’t properly emulsified. This can result in a soap that is lye-heavy, or soap that will separate (you see oils floating in your mixture) or be prone to DOS (dreaded orange spots) later on.

One common cause of false trace is the temperature of the ingredients. If the oils and lye are too cold, below 32°C (90ºF), they won’t properly emulsify, causing the mixture to appear thick and trace-like when it’s really just a result of the cooler temperatures.

Similarly, if the mixture gets too cold while it’s being blended, it can cause false trace. This is especially true if your oil mixture contains a lot of solid oils and butters (around 50% or more). What you believe to be trace is actually the solid oils getting solid due to the low temperatures.

Another common cause of false trace is the use of certain additives. Some additives, such as clays or certain colorants, can cause the soap mixture to thicken prematurely, leading to false trace. It’s important to use these additives carefully and to be aware of their effects on the soap mixture.

False trace – image from

I must say, I never experienced false trace. The only time I was afraid I had failed my soap batch was with 100% olive oil soap. It took forever to harden and I thought I had false trace. However, the soap mixture, even if too soft, was not “separating”. It is just a characteristic of olive oil soap, it takes a long time to trace, harden and cure. So I just had to be patient and let it solidify in the mold. It took almost one week.

To prevent false trace, it’s important to keep the ingredients at the right temperature and to blend them thoroughly until they are fully emulsified.

One technique for preventing false trace is to warm up the oils to a temperature of around 38-43ºC (100-110°F), then slowly add the lye to the oils while blending continuously. This can help ensure that the mixture is fully emulsified before it thickens. All my recipes work around these temperatures and it’s not by chance. It’s to prevent false trace, and reach trace after a few minutes of blending. Some recipes use room temperature, but that’s because we want to slow down trace to make colorful swirls, for example.

If you do encounter false trace, there are several techniques you can use to correct it. One technique is to continue blending the mixture until it properly emulsifies. This is probably the safest and surest way to reach trace, you just need a bit of patience and to trust the chemical reaction. Another is to heat the mixture slightly using a water bath or microwave, then blend it again, but I won’t advise this one. You need to be careful when heating the mixture, as overheating can cause the soap to scorch or separate.

False trace can be a frustrating issue in soap making, but it’s important to understand its causes and how to prevent it, especially if you want to formulate your own soap. By keeping your ingredients at the right temperature, around 38-43ºC (100-110°F), and blending them thoroughly, you can ensure that your soap mixture properly emulsifies and reaches true trace. Pay special attention if you are using a high percentage of solid oils or butters.

If you are just using recipes from the net or a book, be sure that most recipes are formulated to prevent this and other issues. All you have to do is to follow them.

How Long Does it Take to Reach Trace in Soap Making?

The time it takes to reach soap making trace varies depending on the ingredients used, temperatures, and method of mixing. Using a stick blender or immersion blender speeds up the process up to a few minutes, while stirring by hand takes hours. Generally, it can take anywhere from less than one minute to 30 minutes to reach trace.

Can You Overtrace Soap?

Yes, it is possible to overtrace soap. Overtracing, also called soap acceleration, occurs when the soap mixture becomes too thick and is difficult to work with. This can happen if the mixture is blended for too long or at too high a speed. Some ingredients may also cause overtrace, especially if they contain certain types of alcohol, like fragrance oils. Overtraced soap becomes difficult to pour into molds and may have a rough or uneven texture.

soap acceleration ricing
Overtrace caused by ingredients (soap ricing)

How Do You Fix Overtraced Soap?

If you overtrace your soap, there are a few things you can do to fix it. One method is to use a hand mixer to blend the soap mixture back to a more pourable consistency. However, this will only delay a little bit soap acceleration. Another method is to add a little bit of hot water to the mixture to thin it out. But be careful not to add too much water, as this can affect the quality of the soap.

My advice in this case is to abort any sort of designs if you were planning them, pour your remaining ingredients immediately, mix and pour the soap batter into the molds. It’s stressful, but you will save your batch.

What are the Benefits of Achieving Trace in Soap Making?

Achieving trace in soap making is essential to creating soap. It ensures that the oils and lye have emulsified properly and that the soap mixture will harden and cure properly. Soap that has reached trace has a smooth, creamy texture, and is easy to pour into molds or shape by hand (with heavy trace).

In addition to ensuring the quality of the soap, achieving trace also allows for the addition of fragrance, colorants, and other additives. Without trace, these ingredients would not be evenly distributed throughout the soap and could clump or settle in one area.

new blue layer
Making drop swirl layers with medium trace

Another benefit of achieving trace is that it allows for greater control over the soap making process. By monitoring the mixture for trace, you can adjust the temperature and blend time to achieve the desired consistency and texture. This level of control is especially important when creating more complex soap recipes that require precise blending and curing times.

Finally, achieving trace can be a satisfying and rewarding experience for soap makers. Watching the mixture transform from a liquid to a creamy, emulsified state is a visual reminder of the skill and creativity involved in soap making. It provides a sense of accomplishment and pride in creating a product from scratch that is both functional and beautiful. If you have the soap making “bug” in you, this is how you will feel when reaching trace.


Soap making trace is essential for creating high-quality soap, allowing for the even distribution of additives, providing greater control over the soap making process, and a satisfying and rewarding experience for soap makers. It has certain visual characteristics you will learn to identify with experience. You can use trace to your own benefit, in case you wish to make soap with more complex designs.