Soap Making Troubleshooting

Why Did My Soap Turn Brown ... and Other Questions Answered.

Soap Making Troubleshooting

Reading Time: 5 minutes

Soap making troubleshooting can be an ongoing learning experience. If you find yourself wondering, “why did my soap turn brown,” learning that the common fragrance oil component, vanillin, causes browning will help you to predict the behavior of your next batch. Part of the art of creating good soap is being able to control the batter and produce a consistently pleasing result. Granted, most soap mistakes can be salvaged to create usable, if not beautiful soap. Soap making troubleshooting is vital to the process of becoming a proficient soap maker. One of the most gratifying parts of soap making, troubleshooting helps you to better control future batches. Next time you will know the answer to “Why did my soap turn brown?” (It’s the vanillin!) 

False Trace Soap

False trace soap is one common problem that can happen. When it has only come to false trace, soap has a higher than normal risk of separating in the mold. This looks like a layer of oil on top of, or under a crust of caustic soap. What does false trace soap look like? It is soap batter, often at room temperature or cooler, that thickens without having fully reached emulsion state. When you stir a false trace soap, there will still be a swirl of unincorporated oil spinning through the bowl. False trace soap often occurs very quickly after mixing the oils and lye, and sometimes even before the use of the stick blender. There may be lumps of thicker soap in a thinner batter. To prevent false trace soap, use a higher soap making temperature, around 100-130 degrees Fahrenheit. This will prevent the butters in your recipe from thickening up before emulsification is reached. If you experience false trace soap, keep blending! To save the soap, you need to reach full emulsification. The soap will probably get quite thick. Keep pulsing with the stick blender and alternating with the hand mixing as needed. You may need to use the Spoon Plop Method to get it into the mold. Another alternative is to heat the batter in short bursts of 30 seconds in the microwave, to increase the temperature enough to re-melt the butters in the batter before blending to full trace.  

Unmolded while too soft. Image by Tiffany Strong.

Soap Seizing

When a misbehaving fragrance oil or too much honey causes soap seizing, you may suddenly find yourself with soap-on-a-stick. If this happens, it is very important not to try to glop it into the mold as-is. There would be a strong risk of lye pockets and fragrance pockets in the resulting soap. Instead, leave the soap in the bowl and do your best to encourage it to reach a full gel — a heating pad or a pan of hot water underneath can be helpful. Keep watching it for a full gel state, which will make the batter become soft and runny again. At that point, you can thoroughly mix your soap batter and pour. To prevent soap seizing, the best protection is to research your fragrances before using them. Not only do they need to be safe for soap making, but the seller should answer questions about acceleration, ricing, and discoloration in cold or hot process soap. If the seller does not provide this information for a fragrance oil, it is worth your time to look up the comments from other users to see what their experiences have been before you invest in a fragrance oil that might cause problems. To prevent soap seizing from too much honey, simply do not use more than one teaspoon of honey per pound of base oils in your honey soap recipe.  

Air bubbles in batter. Image by Tiffany Strong.

Too Much Fragrance Oil in Soap

Adding too much fragrance oil in soap can also be a source of problems. Besides being too strong of a fragrance, too much fragrance oil is not safe for skin use. Each fragrance oil has a Recommended Maximum Usage Rate specifically for soap. Make sure you always adhere to these guidelines to prevent possible skin reactions from your soap fragrance. Another problem of too much fragrance oil in soap is that the fragrance can separate out, creating a strongly odorous, oily sludge in the finished soap. Unfortunately, adding too much fragrance oil in soap results in a soap that cannot be saved as-is. Even if you hot process the soap and therefore burn off some of the extra fragrance oil, there is no way to measure whether or not enough has been burned off to make it safe. An option for salvaging this soap is to shred it and use the shreds as “confetti” in an unscented soap batch.  

Oils going rancid and turning yellow. Image by Tiffany Strong.

Lye-Heavy Soap

Producing lye-heavy soap is another possibility. This one is difficult to save unless you know how much extra lye you used. A possibility is rebatching the soap in a crockpot on low heat, adding extra oil one ounce at a time and cooking until the batter tests at a safe pH of 9-10. The problem with this approach is that it is hard to know exactly how much superfat the finished soap contains. It may still be a low superfat soap, which means it might be drying to the skin although it is safe to use. In most cases, a lye-heavy soap is best called a loss to be safe.  

Partial Gel

Partial gel can occur when a soap heats up in the middle but does not heat up enough to spread the gel phase all the way to the edges of the soap. The result is a circle of darker, slightly translucent-looking soap in the center of each bar. Never fear, this is perfectly benign and the resulting circle of gelled soap is simply a cosmetic issue.   

Partial gel ring. Image by Tiffany Strong.


Problems with full gel can include overheating, heat tunnels, and cracking. One your soap has gelled to the point where it will soon reach the edges, it is a good idea to cool it down in a refrigerator or freezer to prevent overheating, which can result in heat tunnels and cracking. Dry heat tunnels are simply a cosmetic issue and the resulting soap is fine to use. However, sometimes heat tunnels can ooze oil or contain lye crystals. In this case, the part of the soap affected must be cut off and discarded for safety. Cracking of the surface of the soap is also just a cosmetic concern, and often can be smoothed out once the soap cools down a bit. If the cracks are small and just starting when you intervene, they will often close up on their own.  

Overheating and cracking on edges. Image by Tiffany Strong.

Keeping good notes of your soap making troubleshooting experiences is a good idea. This will help you learn to avoid pitfalls such as soap unexpectedly turning brown, overheating, seizing or partially gelling. Making sure to avoid all distractions while soaping can prevent problems such as a lye-heavy soap or too much fragrance oil in soap. With a little experience and the benefits of your notes, you can develop soap recipes that come out consistently time after time. What soap making pitfalls have you experienced? How did you save the batch, if you were able to do so? We would love to hear your comments! 

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