A student of mine recently contacted me for some advice about one of the most common soapmaking mishaps when using the cold process method: soap seizure. No, the soap doesn’t go into convulsions (although it’s been known to make some soapmakers have fits!). As a soap batch is being mixed, it’s usually the consistency of cake batter. Sometimes rather thick cake batter, but smooth and pourable nonetheless. When a soap seizes, it thickens unexpectedly and suddenly, sometimes ending up as thick and curdled as applesauce. The worst is when it becomes so hard, so fast that no amount of stirring or blending with a stick blender will fix it. You end up with a hard mass of soap in the pot right in the middle of mixing; what soapmakers call “soap on a stick”. *shudder*
The usual culprit in this sorry business is the scent: either natural essential oils or (much more frequently) synthetically manufactured fragrance oils. In general, anything that smells spicy (cinnamon, clove, ginger…) or very floral (jasmine, lilac, gardenia…) tends to speed up the chemical process that turns the soap batter into soap bars. When it speeds the process so much, you don’t even have time to finish blending in the scent and BOOM!: seized soap.
It’s no shame when it happens. But there are ways to avoid (or at least manage) a soap seizing.
Research your fragrance
Chances are that someone else has already made soap with whichever fragrance or essential oil you want to use. Forewarned is forearmed! First, check with the supplier of the fragrance oil. The best ones have soap information right on their website listing any issues like discoloration or acceleration (soapmaker code for “watch out with this one!”) If the info is not on the website, get in touch and ask. If they don’t know, it may not be worth risking it.
Also check The Soap Scent Review Board, an online community of soapmakers that shares their experiences with hundreds of fragrance oils and essential oils from dozens of suppliers. See if anyone else has used your fragrance oil of interest and what the experience was like. And remember to add to the community by adding your own soapmaking experiences, good or bad.
Doing research may save you a lot of aggravation, but remember: different soap recipes may react differently to the same fragrance. Someone else’s experience may not be exactly yours. Testing a new scent is always a bit of a risk.
Dilute the scent
If you have a fragrance or essential oil that you really want to use but you know (or suspect) that it will be problematic, you can try to dilute the oil, and hopefully minimize the acceleration. Instead of adding the scent after the base oils and lye are mixed (as most folks do), add the fragrance oil to the base oils before adding the lye solution. This way the scent is blended throughout the oils and may react better in the presence of the lye.
Cool it down
Soapmaking is chemistry, and the warmer the chemical reaction the faster it will head to completion. To slow down the reaction and keep your soap batter smooth longer, try cooling your base oils and lye solution before mixing them together. As long as the oils are still liquid and flowing, having everything even as cool as 70ºF will still result in great soap. And it may give you enough time to get your soap blended and into its mold before it hardens up.
Even after taking all the precautions, no one can guarantee that they will never experience a soap batch seizing (soapmaking is an adventure!). But I hope that these tips may help you get the smooth, great-smelling soap that you’re looking for!
What was your worst soap seizure? Do you have any other tips that might help? Leave a comment and let’s learn from each other!