Monday, March 5, 2012

Soap Loaf and Lye

Day old soap loaf
A week ago I made a new batch of soap. This soap is a custom batch for a friend who is also a soap maker. We are creating a very plain soap raw material (soap base) that she can use to make a bar of fancier soap that will have fewer of the ingredients some of her customers find irritating to their skin and allergies. This base is oil, lye, and water. She doesn't make the initial base because she is the mom of a small child and she prefers not to keep lye in her house.

The initial base or basic soap is what most folks call lye soap. Soap-makers refer to this type of soap as cold process soap. All soap normally used is made with either lye or another strong base. The lye is mixed with oil or fat and water in a careful and controlled manner (don't use lye unless you read the directions and know what you are doing, also don't make soap until you read something that explains the dangers to you and others. It is safe if you are careful and KNOW what you are doing. And it is NOT SAFE if you don't.

When people kept stock or when they hunted, they used the fat rendered from the animal (lard) and mixed it with lye which came from wood ashes. People often didn't let it cure sufficiently and that is how lye soap got its reputation for harshness. The alkaline lye from the ashes hadn't finished reacting with the fats and making soap. Too much strong base (lye) was still free in the bar and it burned or was very harsh. The goal is to mix just the right amount of oil, lye, and water and let it complete the soap making process (this process is called saponification). Four weeks is the least soap-makers should probably wait, with six weeks being safer. It is hard to wait because after a week the soap looks like the finished product, but it still needs to cure longer.
Slicing for re-batch

Cold process soap can be colored and fragranced, but it is tricky. The lye reaction is so strong that it destroys many fragrances and the whole batch may be destroyed. Many of my favorite smells (carnation, hyacinth, narcissus) aren't available in a form that will stand up to the cold process. So to get that kind of soap it must be remelted or re-batched. You don't have to go through the whole saponifcation process again, but it still takes time and lots of skill. It is art and science.

I may stick to the cold process and ask my friend (SueAlien Creations, see link on page) to make some hyacinth and carnations soaps for me. Or I may get brave and try it too. I am pretty limited in counter space so it may need to wait until we build our new kitchen. Soap is its own universe, there are more shapes, bars, colors and smells out there than you can imagine. It is worth a Google. Next time you grab that bar of soap, take a second and appreciate the process as well as the clean!

Thanks to "Elegant Astronaut" (see blog list) for soap slicing picture.


  1. Just realized I wrote a whole blog about soap making and never once mentioned Fight Club! Missing out on potential audience there.

  2. love and hated that movie :)
    i dont think i've ever used homemade soap...i have sensitive skin, what's it like for pale-faces like me?