Monday, October 4, 2010

To Gel or Not to Gel? Gel Phase and Cold Process Soap

When I first began making cold process soap, I was convinced that proper insulation was the key to making good cold process soap. It seemed like every book I read, every site I visited and every person I talked to had 3 golden rules to soap making:

1) Insulate, insulate, insulate!
2) Let it sit for 24 hours

I was absolutely CONVINCED that improperly insulating or jumping the gun and removing it prior to that magic (if not a bit arbitrary) 24 hour mark would some how irreparably ruin what would have otherwise been a perfect bar of soap. Imagine my surprise when I found out soap makers have options!

Why do soap makers insulate?
The method of cold process soap making naturally generates heat as the lye reacts with the oils. As it heats up, the soap goes through a process called gel phase. Basically, during gel phase the saponification process speeds up, the oils begin to harden and the color usually becomes a bit darker or otherwise morphs (depending on the colorant you are using). Since the gel phase does change the appearance of your soap, it is important that the soap is heated evenly throughout. If the soap heats unevenly, you may end up with what is called a "partial gel." In a log mold, this usually looks like a odd colored oval running through the center of your soap. This is because, naturally, the soap in the middle will retain heat better, while the soap near the edge will lose heat more quickly. As a result, if left uninsulated, the edges of your soap may not reach gel phase, while the soap in the middle of your mold will. A partial gel is not dangerous, but it may look funny and, if you've spent a great deal of time creating a beautiful pattern in your soap the uneven coloring can be quite disappointing. Insulating your cold process soap helps ensure an even color throughout.

So why would anybody NOT insulate? Well, it goes to reason that if you can get an even appearance by ensuring that the soap HEATS evenly throughout, then you should be able to get an even appearance by ensuring that the soap stays evenly COOL throughout. But there's more...

Preventing Gel Phase
There are a variety of reasons why people prevent gel. Many argue that the colors are richer, the texture is creamier and the scent stronger in ungelled soap. But preventing gel phase isn't as easy as you might think. Cold process soap naturally wants to heat up. If you simply do not insulate, you will likely wind up with a partial gel. You can put your soap in the fridge or freezer, but depending on your recipe and mold, you may still end up with a partial gel. I find that it is easiest to prevent gel phase when I use smaller, shallow molds. I have yet to successfully prevent gel in my log mold! But it can be done! If you are going to try it, there are some important things to remember:

1) It should stay in the fridge/freezer for at least 24-48 hours
2) Forcing the soap to stay cool slows the saponification process. This means it may take several days before it passes the "zap test" and should cure for a full 6 weeks
3) Let it come to room temperature before cutting, or it may crumble

Pros and Cons
Based on my experience, there are some pros and cons to preventing gel:

  • Creamier looking texture
  • Some colors are more vivid
  • Uncolored soap usually appears whiter
  • Some scents come through stronger
  • Can be difficult to fully prevent gel
  • Some colors, like alkenet, look worse
  • It takes longer to saponify
  • It does not seem to last as long in the shower
I personally am an insulator, but I love that there are options and I love to experiment! I always make my batches 10 oz larger than they need to be. The majority goes into a loaf mold, which gets insulated, then I pour the leftover into my ELF massage molds, which go straight into the fridge.  The next day, I can compare the texture and color of gel vs non gel with every recipe I make. I thought ungelled beer soap was a disaster, but turmeric made for a beautiful buttery soap when left ungelled. For me, the fun is in the experiment... and the thrill of breaking all the rules!


  1. I definitely prefer the look of un-gelled as well...sometimes gelling can give a sort of dirty colour to the soap. Even though it seems from your blog that it's difficult to get an entire loaf to not gel I'm going to give it a go anyway. Maybe it will work when using room temperature method!

  2. Good luck! I know other soap makers who never gel and their soaps turn out beautiful... I don't know why it is such a challenge for me (although I suspect it is because I made my mold with 2 by it it pretty well insulated to begin with.)

  3. I never gel my soap. I like the creamy look it gives and use pastel colours a lot. Here is my blog if you want to check out what I make and how it looks