From Light to Dark. Gel Phase. A Handy Soaping Tool.

Gel Phase

This weekend I made a batch of beer soap. I am waiting for more supplies to arrive and had just enough coconut oil for one batch of soap. I've been wanting to add more beer soap to the shop but have been struggling with the inspiration for a new soap design. I've learned that forcing creativity is almost always an inevitable fail for me. 

I finally decided on a dark IPA for my liquid to work with but was still a bit stumped on my design. I did know one aspect of my design though, in that I wanted my soap to be as dark as it could possibly be. This was a batch made with a dark IPA and I wanted it to be different than the light, lager I had made a couple months back.  

The video below is of the beer at the bottom of the warmed oils and butters. 

Before I even started making my soap, I knew I would be putting my soap through gel phase. Gel phase, simply put, is when your soap heats up during the saponification process, either intentionally (i.e., insulating your soap with a wooden top or towel over it to keep heat in, or placing it on a heating pad to create more heat) or unintentionally (sugars added to soaps will result in soap heating up, or the addition of fragrance oils). Saponification is a chemical process where the fatty acids or triglycerides in oils react with lye to create a hard bar of soap with a small percentage of glycerin remaining in the end product. 

When gelling soap though, it is a fine line between forcing your soap to go through gel phase and creating literally a volcano of soap! Luckily, this has not happened to me yet, though I have had some nice cracks in the tops of my soap. I will be sure to post a picture if and when it does happen. Click here to read more about soap volcanoes.

chocolate soap

Look closely at the second bar in from the left side, and the last bar on the right side. See the deep cracks? Luckily I caught this soap before it volcanoed and put it outside in the cold winter air to cool it down quickly.

In wanting to create a darker bar of soap, I had a couple of options. I could cover my soap with a top, to hold the heat in as my soap naturally heated and went through the saponification process, I could place my soap loaf on top of a heating pad to create more heat, or I could do both. I opted for both with this batch.

This is what soap batter looks like when the oils, butters and lye solution meet!


After pouring my soap into the mold and finishing my design on top, I opted for all three options. I put a wooden top over my mold, then I put the mold on top of a warm heating pad, and finally I covered it with a towel to keep the heat in. My soap room is in the basement and is very cold this time of year. If your soap room is warmer, you might not need this much heat to induce a gel phase.

 gel phase


gel phase 

Than I sat by and waited, checking the soap every so often to make sure it was not overheating. You can do this visually or you can use a thermometer (I have an infrared thermometer to test the temperature of my butters and oils to ensure I do not overheat them when creating my recipe).  

Here is what my soap looked like before I put it on the heating pad. I love how shiny soap is when it is freshly poured.  


The next video is of the soap going through gel phase. You can see how the color is deeper in the middle than on the ends. Gelling occurs through the center first, and then works it way out toward the ends.  


And finally, here is my soap the next day, after it has insulated overnight. Note: the heating pad was turned off once I determined the soap had gelled approximately 90% of the way. Don't leave your heating pad on, it can cause a volcano and could potentially be a fire hazard.  


The great thing about soaping is you have a lot of freedom to be creative. You also have to resolve yourself to the absolute fact that no two soap batches or even bars from the same batch will ever be the same, well unless you have a very plain soap with no designs or additives (plain soap is beautiful too!). There are so many variables in soaping that play into your end result, e.g., temperature, humidity, additives, etc. that make soaping fun and challenging.

I LOVE cutting my soap and can barely contain myself in the morning. I usually run downstairs in my pajamas, rip the towel and wooden top off my soap and give myself a little talk about how I need to wait to cut the soap!!! My family yells at me, "Are you cutting the soap Mom!!!???? You know you have to wait!!! You are so impatient! You are going to be mad at yourself" Yes, yes I am impatient. I'm learning patience, though as you will come to know me, patience and I are not friends. 

Waiting to cut your soap can have a big overall affect on the appearance of your soap. If your soap is too soft and you un-mold it, you can damage it, making all your hard work for not. Wait too long and you might have a tough time getting your cutter through it. Most of my soaps are ready to be cut 1-2 days after making them. Having said this, I think I've only ever waited twice for the second day cut!!! I'm bad.

So how long did I wait for this one? As I am typing this I am still staring at my soap in the mold. I'll let you know when I cut it. While we're waiting, how about a picture of soap that only partially gelled. 

partial gel phase

See the circle in the center? This was a batch of honey-oatmeal soap that started to gel in the center and then stopped. I most likely turned the heating pad off too soon on this one.

The good news with a batch of soap that has partially gelled is that there is absolutely nothing wrong with it. It is just sort of, well...ugly. I suppose if you are going for some effect where you want a dark circle in your soap, you can attempt a partial gel but personally I like the look of a fully gelled bar of soap.

Hopefully our new batch of beer soap will be fully gelled. Until the final cut, we'll have to be patient, together! I told you it was hard to be patient when cutting soap!! 

Have a great rest of your weekend everyone and check back for the end result!!

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  • Thank you for the info. As I am new to soap making. My honey oatmeal soap has gelled partially. I thought this will affect the final soap but your article has calmed me down. Nothing wrong with my saop ( and honestly I love the darker circle inside it) . Thanks

  • Loving the blogging!

  • Great post! Love learning about the soap making process!


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