Sunday, November 1, 2015

Activated Charcoal Soap and A Teachable Moment

Last night, after all of the Halloween festivities were over and the house was quiet, I unmolded the charcoal soap. I was a little cautious, a little leery as to what I would find. Why, you ask?

Well, let's go back a bit. I left the soap in the oven at about 160ºF for about an hour, then turned the oven off and left it until it had cooled. When I took it out, it looked like this:

That's not ash. I know what ash looks and feels like and this ain't it. It's more like orange peel, tiny little bubbles all over the entire surface of the log. I've had something like this happen only once before, with my last Taiwan Swirl soap.

In the case of the blue swirl, though, the soap stayed soft for quite some time. It's fine now, after its full cure but it did concern me. So, understandably, I was a little leery about the charcoal soap. Apart from the bubbly top, though, I had no reason to be concerned.

I'm thrilled with the resulting soap, glycerin rivers and all!

After posting a question in the Soap Making Forum about what was happening to my soap, I received numerous suggestions, many agreeing that it was probably ash... it isn't. One poster commented that it likely had to do with high water content and overheating. She referred me to Auntie Clara's amazing blog and this post in particular: Glycerine Rivers: Trying to Understand Them.

The post goes into the science behind glycerin rivers (see the lighter splotches? Those are glycerin rivers) and is very detailed but absolutely fascinating. Without repeating what Auntie Clara has already written so eloquently about, I learned that if I want to avoid the results I ended up with, and if I want to CPOP (cold process oven process), I can drastically reduce the water content in my soap. Higher water content in the soap will result in faster gel and higher temperatures, which is the culprit in this case.

I'm not complaining, though. I love the look of the soap. As for the top, I simply trimmed it off.


  1. Love the look of that bar! And to smell like licorice as well? I'm envious of whoever gets to soap up with that!

  2. I think the licorice charcoal soap looks amazing too! I bet it smells delish! Love the swirls - I'm trying to work up the courage to retry using dividers in a loaf mold - my first attempt wasn't pretty as one of my layers volcanoed... I wonder if the bubbles on the top are just air bubbles caused from heat? This happens to my soap when I force gel.
    Happy soaping!

  3. I'm pretty sure that it IS a case of overheating. I'll have to try again and see what happens.

  4. This is very pretty. I've never tried this colouring technique.