Monday, April 6, 2015

Cry Me a Glycerin River

One of the many benefits of using handmade soap is the natural glycerin content. Glycerin is a natural by-product of handmade soap, and it's great for nourishing your skin. Glycerin is a humectant, meaning that it moisturizes your skin by drawing moisture out of the air and into the skin. Commercial beauty products often add glycerin to expensive creams and lotions for this reason. Luckily, glycerin is naturally occurring in handmade soap, so we don't have to go to the trouble of extra processing to reap its benefits.

When making soap, sometimes the science aspect of it leads to unexpected results. This has been the case for me recently, as several of my soaps have developed "glycerin rivers." Sounds lovely, doesn't it?

A river...of glycerin...runs through it
The crackling, mottled, marbled look of the soaps shown above are examples of glycerin rivers. It's purely a cosmetic issue, meaning that it only affects the look of the soap, not how it works and feels on the skin. Still, I was a little bit disappointed in these batches since the look didn't really fit into the overall designs that I had in mind here. On the other hand, I've had some customers really like the overall effect. If that's the case, then I meant to do that...

Glycerin rivers in Beer Soap


Glycerin rivers in my Cafe Mocha soap

After doing some research, I found some possible culprits of glycerin rivers:

  • Soap overheating, either from a higher soap making temperature, insulation, using high-sugar liquids in the soap making process (beer, milk, etc.), or even some misbehaving fragrances
  • Using certain colorants (especially Titanium Dioxide, but also Iron Oxides and Ultramarines)
  • The water discount used in the soap recipe (this blogger suggests using a 1 part lye to 1.4 parts water, which is much less water than my typical recipes)

Armed with this knowledge, I think I see where my issues lie, and can make steps to take this unwanted element out of my designs. I have to admit it to myself, though; The marbling effect does make the soap look pretty cool.