How a bar is made
Cold process soap, start to finish. And why the ingredient list reads Sodium Olivate instead of "olive oil".
It starts with a reaction
Soap is not a mixture. It is what comes out of a chemical reaction called saponification: oils and lye meet, and both of them stop existing.
Everything before the arrow goes into the pot. Everything after it is what comes out. It is the same as baking: flour and eggs go in, and what you take out is called cake — not "flour with eggs".
The glycerin stays in
Look again at what the reaction produces. The reaction does not only make soap: it also makes glycerin, and in a cold process bar that glycerin stays inside. That is why it appears in the ingredient list of every soap.
Glycerin is a humectant - a substance that attracts and holds water. It is worth something on its own, and industry knows it: in large-scale production the glycerin is separated out and sold off for creams and lotions. What is left behind is a detergent bar. I work in small batches, with no way to separate it and no reason to, so it stays where it was made.
That is why the label does not say lye
Every real bar of soap is made with lye. There is no other way, and there never has been. But by the time a bar has finished curing, there is no lye left inside it: it was used up entirely in the reaction.
And for the same reason, the list reads "Sodium Olivate"
This part surprises people. A cured bar holds no olive oil either — it was transformed, just like the lye. What is in there is something else, and that something has its own name:
| What goes into the pot | What is in the bar |
|---|---|
| Olive oil | Sodium Olivate |
| Coconut oil | Sodium Cocoate |
| Shea butter | Sodium Shea Butterate |
| Castor oil | Sodium Castorate |
| Avocado oil | Sodium Avocadate |
| Cocoa butter | Sodium Cocoa Butterate |
| Pork lard | Sodium Lardate |
| Beef tallow | Sodium Tallowate |
Always the same pattern: Sodium (from the lye) + the name of the oil + ate, the ending chemistry gives to something that has already reacted.
Not everything changes name. Fragrance, clays, micas, lavender powder and coffee go in once the soap is made, or never react with the lye at all. Those keep their usual names on the list.
On the bar's own label the oils go by their everyday names: olive, coconut, shea. That is how I buy them and how anyone recognises them. Here on the site is the full list, with the name each one takes after the reaction. It is the same thing at two moments: what went into the pot, and what came out.
Superfat: oil I leave in on purpose
I could work out the exact amount of lye needed to consume every last drop of oil. I do not. I always leave a little extra oil in the bar, unreacted — soapmakers call this superfatting.
That margin is the difference between a bar that washes and a bar that is a pleasure to use, and it is where the craft sits: every one of my recipes has its own, and I have moved it over time until each soap landed where I wanted it.
Then you wait
Once the bar is cut, the cure begins. Weeks on a shelf, in open air, losing water little by little. The bar hardens, it lasts far longer in the shower, and the lather turns finer.
It is the slowest part and the one you cannot skip. A young bar dissolves in the dish; the same bar, cured, lasts for weeks.
If you want to see what goes into each bar and what does not, it is all on the ingredients page.