Posted by on 3/2/2021 to Let's Talk Soaping
The Not So Beautiful River: All About Glycerin Rivers & Prevention In Cold Process Soap
What is Glycerin in Soap Making?
Glycerin is a natural by-product that happens when soap is made. Glycerin itself may effect not only the look, but potentially if it were to congeal more in one area of the soap, it effects the texture as well, making the soap feel soft in a specific area.
With large scale commercially made soap, glycerin is actually separated out during soap making to sell to manufactures, food companies and so on, as a commodity.
However, glycerin is wonderfully moisturizing for the skin. One of the great things about homemade soap is that when it's made, glycerin is distributed throughout each bar of soap.
Maybe you have used store bought soap, and it tends to leave your skin feeling dried out, this is one of those reasons.
What are Glycerin Rivers & Why do they Occur?
One of the more common issues, besides discoloration and acceleration in cold process soap making, is that of glycerin rivers.
Glycerin rivers do not necessarily effect the performance of you soap, however it can severally alter it, aesthetically.
Some refer to glycerin rivers as crackling or glycerin separation as well. True glycerin rivers are most often caused from temperature issues, like overheating as well as cooling issues during saponification.
They can commonly be more pronounced in recipes that include certain colorants as well, especially with pigments because of their densities compared to colorants such as mica's.
One of the more common pigments is titanium dioxide. In fact, some people refer to glycerin rivers as "titanium dioxide rivers" as this white substance makes them more visible.
Titanium dioxide is a white pigment is often-times used to soften colors to help keep a soap a lighter shade when using a fragrance that discolors. However, using it can encourage glycerin rivers throughout your soap or in certain areas.
Some titanium dioxide pigments are water soluble. This is another important thing to keep in mind because in our experience, excess water or liquids in your soap can also contribute to glycerin rivers, because of overheating. If you indeed dissolve your titanium dioxide in water, it's important to keep in mind how much additional water is going into your batter. You can help minimize this issue by doing a water discount in your recipe.
Having said that, many soap makers "pre-mix" there colorants. Why? Simply because when premixed in a lightweight oil, pigments, micas and other powdered colorants will distribute better and more evenly in your batter when you add them. You won't have to worry as much about overmixing your batter and accelerating trace because of it. Even a simple stir with a spatula can incorporate some of the colors if mixed beforehand.
Related Article: Working with Colorants in Cold Process Soap Making: How to Premix
While on he subject of excess liquids, certain liquids themselves can increase the likelihood of glycerin rivers. These include liquids that have high sugar content, like milks, beers or fruit juices.
Another idea to keep in mind while troubleshooting issues you may have with glycerin rivers, is the fragrance that you chose. Fragrances that are higher in floral notes, also tend to be more prone to causing glycerin rivers
If you're a soaper that gels your soap or forces gel, this can increase the likelihood of glycerin rivers happening due to the potential for overheating.
So, the question is, how do we prevent glycerin rivers in cold process soap making?
How to Prevent Glycerin Rivers
#1. Overheating: The best way to avoid glycerin rivers is by not allowing your soap to overheat. This may mean incorporating a water discount into your soap recipe. This may also entail keeping a closer eye on your soaps once you've insulated your soap batch!
#2. Mixing the Colorants: Mix your colorants well before using them in your recipe. Usually this is done in a lightweight oil. It's better to disperse titanium dioxide in a lightweight oil (in our opinion), then in water.
#3. Fragrance Choice: Make sure to always research you fragrance choices. Are there performance notes? Are their customer or other soaper reviews? Ask the company themselves with a simple email if no performance notes are given.
#4: Lower temperature soaping: As mentioned before, overheating can lead to glycerin rivers, so try soaping at a lower temperature. We soap between 85-100 degrees F and hardly ever run into glycerin rivers.
#5. You may try to use a different mold. Certain molds (like wood) insulate soap better then others, meaning they could heat up faster or more then soap in other molds. Try individual molds, these will heat up much less then a large soap loaf mold.
Hopefully some of these tips will help you avoid glycerin rivers in your cold process soaps. Some people actually don't mind glycerin rivers and think they just add another dimension you their soaps!
Please be sure to leave a comment on a time when you ran into glycerin rivers and how you rectified the issue on the next batch! This is a great way to help other soapers avoid similar mistakes!