One of the topics that I see posted about in our Facebook Group Saponification Nation is people asking about white spots in their soap. This can be caused by a few different reasons. Let’s explore!
So I recently made a soap in Saponsification Nation to show people how to do this beautiful drop swirl design. Upon cutting…I saw them! Cue horror music. Stearic spots! I immediately knew why. I had my lye solution in the fridge to get ready for the Facebook Live and left it in a little too long. When I took it out, it was 60 degrees F. A bit too cold to soap with. My oils were about 80 degrees F.
The combination of the lye solution and base oil low temperatures created the perfect environment for stearic spots to form.
Just a side note. In the soaping community we call them stearic spots but really they can also be palmitic acid spots or actually a combo of both. Both are high melt-point oils. Palmitic acid melts at 145.2 °F and stearic acid melts at 156.7 °F. So for the purposes of this article, we’ll just call the issue stearic spots. When you look at the fatty acid profile for certain oils, they can contain stearic + palmitic acid. So for example, palm oil 44% palmitic acid and 5% stearic acid (on average). Shea butter is 5% palmitic acid and 40% stearic acid (on average). Most of your solid oils and butters are going to contain higher amounts of stearic and/or palmitic acid.
So if stearic acid has a melt point of 156 °F, do you have to mix your soap at that temp? Heavens no. Since you’re using a blend of oils, it drops the melt point of the total mixture so that you can mix at lower temps.
The high melt point is the issue. If you mix with your ingredients at too low of temperatures, the stearic/palmitic acid will start solidifying just a bit. Not only can you get the stearic spots, but you can get false trace. False trace is when the mixture starts to solidify, looking like trace; but it is actually the high melt point oils starting to solidify.
I mixed this batch at way to low of temperatures. My normal temperature range for swirling soap is 85-100 °F for both the oil mixture and lye solution. This helps to keep things moving nice and slow to give me time to color and swirl. But it isn’t cool enough to give me false trace or stearic spots.
Here is a closeup.
For more tips for swirling, check out our free guide, Cold Process Soap Swirling Tips.
Some tips for preventing stearic spots.
- Soap at warmer temperatures if you are soaping below 85 °F. If your soap is full of oils high in stearic/palmitic acid then you might even consider soaping a bit higher, such as at 100 °F up to 120 °F.
- Melt your solid oils first until completely melted. Then add your liquid oils. Some soapers melt their oils just a bit and stir to melt the rest. This can be an issues if your temps aren’t high enough to melt the stearic/palmitic acid that hasn’t completely melted yet.
If you get them, don’t worry. As long as they don’t zap or ooze, then you are probably okay. They are simply a cosmetic issue.
To test if they are stearic spots and not wire cutting spots (see below), cut a piece with a smooth edge knife. If they disappear, they might be air bubbles that are magnified by using a wire cutter.
I tested this by cutting a slice using a knife. Still there. Definitely stearic spots.
Wire Cutting Spots
I also wanted to mention another issue that might give you spots on your soap. This is from using a wire soap cutter to cut soap with tiny air bubbles. You’ll get little pimply looking marks. They are more round than the stearic spots.
Another way you can tell if they are from your wire cutter is to cut a piece of the soap using a smooth knife. If you don’t have the spots, then it is from air bubbles/wire cutter. If you have spots, it could be the stearic issue.
Here is an example of the bubble issue.
Looking closer, you can actually see where the bubbles were!
To test, below I cut with a smooth knife. They disappeared. That is how I know they are bubbles and not stearic.
Using a straight knife (as opposed to serrated) smooths the bubble cavities as you cut.
You can also have a combination of stearic spots + air bubbles. So if you have white spots in your soap, it could be a combo of them both.
Some tips for preventing wire cutting spots.
- Check your stick blender to make sure that it is not introducing bubbles to your soap.
- Burp your stick blender before you use it. To do this, simply insert it into your oils, tilt it to the side and the air will be released out.
- Stir by hand after you mix using your blender. This helps to pop bubbles that might have formed when mixing.
- Be sure to bang your mold down once your pour your soap. This can help bubbles rise to the surface and pop.
Many new soap makers immediately see white spots and think that it is lye. As long as your lye completely dissolves, this is not usually the case.
Mixing issues can cause lye heavy areas in your soap, but it looks something like this.
For any spots or areas that you think might be lye heavy, you can simply do a zap test to check. Simply touch your tongue to the spot and see if it zaps you! If it does, then it is lye heavy.
I hope this helps you troubleshoot the white spots in your soap!
p.s. Want to watch me make the beautiful black and pink soap? Check it out below. 🙂