If you’re not familiar with soapmaking, you might not know that making soap with 100% milk (no water) is notoriously difficult. You have to add lye to milk without scalding it. When you add lye to water, the temperature jumps in seconds to over 200 degrees, so you can imagine what happens to liquid milk. It burns almost instantly.
You get around this by adding your lye to frozen milk and stirring it slowly. Hence the problem with scaling: It’s pretty laborious to stir five pounds of frozen milk that long, and now our goal is forty pounds. Sure, you could make soap with 50% milk or water and save your R&D guy some serious angst, but Katy absolutely refuses to compromise the formula (and I love her for it ).
After lots of research, we experimented with adding liquid milk to the oil and blending the lye afterwards. I was optimistic, young, and naïve. We unmolded the next day to a gooey center and awful air pockets. I tried to figure out why by sifting through dozens of issues that can happen with cold process soap and couldn’t find one that fit. We tried again, this time soaping at a lower temperature, adding the lye first, and then the milk. It hardened almost instantly and stubbornly refused to go into the mold. When we unmolded it, it looked horrible, even worse than the first. Why???
Finally, on Friday, I tried soaping at a much lower temperature, insulating our mold with every towel I could find in the studio, and leaving it in for an extra two days. Saponification (what happens when you mix lye and oils) is an exothermic reaction, which means it gives off heat, and I thought too much heat might be escaping, leaving the center of our soaps with that gooey center.
Voila. We unmolded the soaps this morning, and they’re gorgeous. We can now make fully goat milk soaps with liquid goat milk, which means we can make large batches and keep our formula the same.
The next step is getting equipment, and there is SO much to do, but today we are celebrating that it CAN be done!
Joel and Katy