Learn all about the gel phase in soap making
This article breaks down the specialities you need to know about using the gel phase (or not) in your soaping. What is the gel phase? How do I avoid it? Why can it be necessary?
There are many aspects of saponification that soapers need to know and understand. But one stage that can cause the most confusion, especially for newer soapers, is the gel phase.
What is the Gel Phase?
When Soapers talk about the gel phase, they are talking about after pouring your soap into the mould. Now you are anxiously waiting for your soap to harden so you can cut it ready for curing. This is officially the gel phase.
At this point, the soap molecules will cluster together and form a gel. They do this to avoid the water molecules in the mixture. This is why some soapers typically reduce the amount of water they have in their soap when trying to control the gel phase.
Sometimes by doing this, you can also avoid soda ash. Ultimately the Gel phase is caused by the heat generated during the saponification process – i.e. the chemical reaction between the lye and the oils. As the reaction occurs, the heat builds up, and the soap changes appearance.
If you touch the outside of your mould during this time, you will be surprised to feel how warm it is. Sometimes It can reach 80C (180F) during this stage. When your soap gels, it will change from the opaque batter you pour into your mould to an almost translucent gel before settling back to something you will recognise as a bar of soap.
You can sometimes get a partial gel. A partial gel is where the outside of the soap is rigid while the inside is still going through the process and is a bit like Gel. You can wrap it back up into a blanket to keep warm and leave it for another day, or you can go ahead and cut it.
It is a purely aesthetic preference because the soap itself will be usable regardless of whether it has been through Gel or not.
Does The Gel Phase Happen In Hot Process?
Yes. But if you use a crock pot or some other pot, the saponification will happen inside the pot and before you put it into the mould. The hot process is faster to cut because saponification is completed when you have set the soap in the mould, something like 4 hrs. But you can't just leave the soap to bubble away; you need to keep your eyes on it, so it doesn't bubble over. But that process is a whole other article.
Does The Gel Phase Happen In Cold Process?
Yes. It happens after you have poured your soap into its mould and before you cut it.
Does The Gel Phase Happen In Melt And Pour?
No, it does not. By receiving your Melt & Pour base, it has already been wholly through the saponification process.
How Long Does The Gel Phase Last In Soap Making
It depends on the recipe, but in CP, on average, it is 12-24hrs
Why does the Gel Phase matter?
Gel Phase vs no Gel Phase
Your soap does not have to go through a gel phase. Some recipes would recommend avoiding the gel phase altogether. There are benefits and disadvantages to both.
I recommend finding a recipe with an excellent basic foundation and then insulating it or Forcing Gel. Then, with the same formula, try soaping at lower temperatures and putting the mould in the fridge. The result should give you an excellent understanding of which process to follow.
A good guide is that anything with high sugar content, such as honey or milk or if you want more muted colours, should avoid the gel phase (so refrigerate or freeze). And anything with colours that you want to stand out or “pop” should be forced through the gel phase and insulated or kept warm.
How and why you avoid Gel
When making soap with high sugar content, such as honey or milk, soaping at a cooler temperature may help prevent gel formation. The saponification with sugar creates heat and, thus, a gel phase. So to avoid heat then mix your oils and lye when they are cooler temperatures are advised.
Two ways to reduce heat are to increase the quantity of liquid in the soap recipe, and you can prevent Gel by lowering the amount of sugar.
Finally, utilise your fridge or freezer for 4-24 hrs until the soap is firm enough to cut.
The best reasons for avoiding a gel are that it keeps your colours muted. For example, I like my milk soaps to stay white, so I avoid a gel phase by soaping at a lower temperature and putting them into the fridge. If you are soaping with pastels, then this is another good reason to avoid excess heat. Plus, with milk soaps, I don't want them to scold, so putting them in the fridge helps keep the heat away.
How and why you force Gel
Forcing Gel encourages the process (don't ever shout at your soap). There are so many benefits of going through this stage, but you also need to be careful, as if your soap gets too hot, this can cause cracking. I live in a cold country, so I always put a lid on my soap, wrap it nicely in a blanket, and put that in a box. But this would not necessarily work for someone living closer to the equator.
The benefits of making sure you force Gel on your soap are:
- Brighter colours: as the molecules bind together, they can make some of the colours you have added pop.
- More rigid bars: Purely because you have forced all the water out, the bar is naturally more rigid.
- Faster unmoulding: Making soap takes time and can be frustrating. The temptation to peek at your masterpiece can be high.
If you want your soap to go through the gel phase, then try the following methods:
- Mix your Lye water and Oils/Fats at a higher temperature, between 40C-65C (104F-149F)
- Cover the mould, wrap it in a warm blanket and put it in a box. Leave it for 24hrs before unmoulding. It should be firm with no visible difference in colour. But sometimes, you might need to leave it for a little longer; it depends on the recipe.
- Use a heat mat and wrap it in a light towel.
- Use a water reduction – 26/27%
- CPOP: Cold Process Oven Processed. Follow the usual CP steps & pour the soap into the mould. Then in a warm oven, put in the soap and make sure the door stays shut. Depending on the outside temperature, leave for 4 to 12 hrs. Ensure the oven is OFF when you put your soap in there
How to use a water reduction to promote a good gel phase
Using a water reduction recipe, you automatically make the soap hotter. The amount you need to take out will depend on the soap you make and the humidity level where you are soaping.
- For Cold Process Soap: reduce the water amount in your lye calculation by 10%.
- For Low Water Soap: reduce the percentage by 20%.
- For Hot process soap with higher water content: reduce the percentage by 30%.
- For soaps made with 3-5% water content, like melt-and-pour soap, the amount you need to remove is around 15%.
Some final notes on the Gel phase
The above is a good guide, but what might work for me in winter in Germany may not work in summer in Australia – so if you are starting your adventure with soap. Leave the water reduction method to a later stage when you know more about all the different processes involved.
Whether you force the Gel phase or put your soap in the freezer, the result is aesthetic. Measuring the correct amount of lye to oils will impact the final result.
I hope you have enjoyed this article. Please leave me a message below if you have any questions, or if you don't have any questions, then please let me know which method is your favourite and why! Stay curious… Erika
