The Science Behind the Soap

 It is no secret that we love our natural soaps around here. We also talk about them a lot when we take our show on the road. Not only do people love to smell the wonderful oils, but they have questions about what makes ours different and what makes a lye soap natural in any respect?

First, what makes ours different is the clays, the goat milk (creamy lather for days) and the singing soap maker who infuses the good juju into them with her happy outlook and perfectionist tendencies.

Next, let's talk science, because that's more fun. Here is the question I address most often, and the following is the longer version of the answer I provide:

If your soaps are natural, how can they have lye in them?

All soap contains lye, at least in the beginning. If it doesn't, it's just a detergent.  Here's how it happens.

This is the short and fast version.

  • Lye is a base, it's a caustic substance, and you have to be very careful when handling it. The good news is that by the time the soap gets to you, the end user, there isn't any lye present. It's just science.
  • So we start with 2 components: acid + base. When they combine, they form a salt. That salt is soap.
  • In the process of soap forming from the acid (oils/butters) and base (lye + water) there is heat.
  • The leftover water evaporates during curing (shelf time). Glycerin is a byproduct that is a welcome benefit as it a humectant (skin softener that we also love in lotions). 

Triglycerides (fatty acids - oils - butters) + Alkali (base - lye) = soap with benefits:)

The Soap 411:

Okay, so how do we explain the commercial soap bars? Don't they have lye in them? 


Read the labels to see what is in your soap. You may find some of the following:


  • Sodium palmate: palm oil & sodium hydroxide, which is LYE.


  • Sodium tallowate: beef fat, known as tallow, & sodium hydroxide, which is LYE.


  • Sodium olivate: olive oil & sodium hydroxide, which is LYE.

What about liquid soap?

Same thing--still has lye, just a different kind. It just has potassium hydroxide instead of sodium hydroxide. Cream soap? A combination of both! Fun, right? 

So, you get it. Soap has lye before it becomes soap.

That's what is in it.

What's missing from my grocery store soap then? 

Usually the glycerin, which is a great moisturizing agent. Many commercial soap makers extract the glycerin and sell it other companies who make lotion. We'll do a post on making lotions and creams later. There is absolutely glycerin in our body cream, but we don't steal it from our soap.

High percentages of good-for-your-skin oils. Typically, even in the handcrafted industry, a recipe might include equal ratios of coconut, palm and olive (or even canola) oils. We prefer a high percentage of olive oil due to the creamy consistency this provides the soaps with, even if it might take a little longer to cure. I like to say we are inching toward the castille soap (olive oil makes up for 100% of the oil in the recipe). We also superfat our soaps. This means we add more oil than the lye can handle, thus leaving some unsaponified oils for extra moisture. 

What else do we use as far as the oils are concerned?

Coconut - because it's awesome. We also like it as a choice for a hard oil, but use it as a primary ingredient in our salt soaps as well. Did you know that coconut oil, when combined with sea salt, becomes incredibly conditioning as a soap? 

Palm - because it's a nice lathering agent and also helps harden the bar. (Yes, we prefer to use sustainably-sourced palm oil and we verify this from our suppliers, just like we verify that they don't source from anyone who tests on animals. This is what we consider responsible.) 

Castor - Say what? Yes. Aside from the more obvious uses of castor, it is also great in soap for lather, bubbles and as a mild humectant (draws in moisture). 

So that's it. Soap contains lye. We make it and handle it while it is still present and caustic. You are welcome.

Want to learn more about saponification from actual scientific sources? I don't blame you. Here you go!


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