All soap starts with fat. Fat plus lye equals soap. That’s how it’s always been. The only thing you can choose is which fat.
Most choose palm oil. It’s cheap, neutral, and makes a decent enough soap. It’s also soft. It has a low melting point. The soap dissolves faster than it should. We deliberately leave it out, even though it’s a cheap source.
And yes… the rainforest is part of the equation, but that’s another conversation.
Lard works. It has for centuries. But the fatty acid profile doesn’t resemble the skin’s own lipids. The soap turns softer and disappears faster. We don’t use that either.
Coconut makes lather. Loads of lather. But it can dry out the skin, because lauric acid is effective at removing everything… including the sebum your skin produces to protect itself.
But one hundred percent coconut soap beats industrial cleaning agents. It’s the historical basis for laundry soap… the soap people used for laundry stains, greasy shirts, the dishes after a roast goose.
Rapeseed and sunflower aren’t wrong. They’re neutral, local, and cheap. They’re just not the best.
Both are high in linoleic acid… a polyunsaturated fatty acid that’s unstable in soap. It oxidizes over time and gives DOS… orange spots on the soap and a rancid smell. At the same time, the bars are soft and have a fairly short shelf life.
They’re cheap because they’re surplus products from the food industry. We don’t use those either.
As a base, we use beef tallow or olive oil.
Beef tallow has a very high melting point. It makes a hard, long-lasting soap. It has a fatty acid profile that resembles the skin’s own lipids… palmitic acid, stearic acid, and oleic acid. It’s no accident that it feels right against the skin. It’s nature’s chemistry.
Olive oil as a base gives a richer, softer feel and contributes oleic acid, which the skin recognizes. Extremely mild.
A well-known classic from nearly a thousand years ago.
It’s not romantic. It’s a choice. Every fat has a consequence… for the soap, for the skin, and for the shelf life. We chose the best, not the easiest.
Beef tallow or olive. That’s it.