Wednesday, January 24, 2024

Naughty Soap!

The soapmaking process is what is known as an exothermic process; the process of turning oils, water, and lye produces heat. Additives like honey, or milk can increase the temperature in the mold even more. Oatmeal Milk & Honey soap is a notorious heater and this time was no different. I expected that.

I purposely waited for subzero temperatures before making a batch of this soap, one that overheats for me almost every single time. This past weekend, our daytime temperatures were hovering around -12C so I decided it was the perfect time to make a batch. The intention was to leave the mold outside, in the subzero weather. 

Everything was nice and cool; it was looking good. At one point, I lifted the mold to feel the underside; it was pretty warm to the touch so I put a baking rack under the mold. Once the temperature stabilized, after a couple of hours, I brought the soap inside and left it overnight in my unheated soap room.

The next morning, it was time to cut the soap. The first bar was as expected; there was a bit of a gelled circle so I knew it had gotten warm enough in the middle to gel the soap. The second bar surprised me; as I was cutting it, liquid seeped from it as it did from all the other bars until the last bar. And, there was a hole right through the entire loaf. I wasn't sure if the liquid was lye-heavy (caustic) so I was happy I'd put on my gloves.

This is a classic case of overheating. You can see the darker ring just inside the outer edge and then the sponginess in the middle. This soap really wanted to volcano (expand out of the mold) but didn't. Insead, it created a hole throughout the length of the mold.

Seeing this made me think of monster teeth and I couldn't help but play a little...

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