My Soap Journey

My story started, as many do, with Fight Club. The 1999 cult classic gave us the fundamentals of how to make soap. I had to know more.

Soap has been with us for thousands of years. Legend has it that we get the word “soap” from Italy’s Mt. Sapo, near Rome. The women washing clothes in the river found that their clothes got much cleaner at one particular spot for some reason. Well, that reason was easy to explain, now that we understand the science.

Whether this is truth or legend, many languages derive their names for the product from the word sapo. In Italian it’s called “sapone”, French “savon” and English, it’s “soap”.

But soap, by other names, has been mentioned much farther back than that. Sumerian clay tablets dating back to 2,500 BC mention a formula for soap that consists of cassia oil, alkali, and water. “Alkali” being the base of the word, “alkaline”, indicating a high pH, where “acidic” is the opposite, low-pH counterpoint. Either one of these compounds being dangerous to the “neutral pH” of around 6.7 to 7 that composes humans and most of the living things around us.

The chemistry of saponification hasn’t changed much in the past four thousand years. But we’ve gotten better at controlling the process. Tyler Durdin (the antagonist in Fight Club) said, “Soap is the yardstick of civilization”.

I had to know how to make my own soap, so I started doing research. It was bewildering. So I found a nearby Meet-up where the hostess would show us how to make soap in her kitchen. That was an enlightening evening. She was a competent soap-maker, but couldn’t answer questions about the chemistry involved.

I loved the chemistry, I loved the process. I was going to make the best soap around!

Unlike the bars of toxic ick the grocery store sells, natural soap is made from three main ingredients: fat, water, and lye.

“But lye is caustic! I use it to clean my drain, for goodness sake!”, you might say. You might also say, “Fat? Your soap is made from fat? How am I supposed to get grease off my hands with fat?”
Both are excellent questions. The answer to both questions is a single word: saponification.

Turns out that when fats (also known as lipids) are mixed with lye (a strong alkaline, or base), an interesting chemical reaction occurs that results in just trace amounts of lye and fat at the end of the reaction. What is left after this reaction is soap. This reaction has a name: saponification. It’s a very simple reaction that people have known about for centuries.

Getting back to the example of the women washing clothes in the river. Legend has it that, farther up the mountain, they sometimes sacrificed and burned animals. The fat from the animals would run downhill, and rainwater would wash the ashes from the fire. So now we have our three ingredients: rendered fat from the animals, an alkaline from the ashes (in this case, potassium hydroxide–or potash) and water.

The saponification reaction creates a hydrocarbon molecule consisting of long strings of atoms that happen to terminate at one end as hydrophilic (water-loving), while the other end is oleophilic (oil-loving). When you create a bar of this substance, then add water, these long molecules go to work, latching on to oil on one end and then allowing water to wash the whole thing off.

A natural part of this reaction is in the creation of bubbles. The bubbles act to lift the oil off the skin in order for the water to wash it off.

We can control the size and thickness of these bubbles by various oils and other natural additives. We can also control the hardness and moisturizing qualities as well. Plus, we can add things like essential oils and colorants to give the bar the physical characteristics we want.

Now, to collect materials. We need water (easy), a high-pH reactant (lye, aka drain cleaner found at any hardware or grocery store), and some kind of fat.

We raise pigs. We established a relationship with a local butcher shop/restaurant and asked if we could have the leftover food prep. Every day we pick up a trash can full of food and usually a large bin of meat and fat cut-offs from the butchery.

The food, including meat, went to the pigs and chickens, and I got the fat. With a little more research, I found that all you have to do is remove the water from fat and it becomes tallow. This is done by boiling off the water in a double-boiler. I used a crockpot I got from Goodwill for four dollars. Tallow is useful for a lot of things, and I needed a shelf-stable fat that I could use for soap.

I tried a hundred different variations to get the qualities that I liked. First the base, with just fat, lye, and water. I used a “soap calculator”, also called a “lye calculator” to calculate how much lye to use for a certain amount and type of oil, and the amount of water required to make the reaction work. There are several free calculators online, but I ended up buying a commercial software product that allowed me to save my recipes and track inventories, expenses and sales. For a hundred bucks, it was certainly worth it, and indispensable for starting a soap business.

Once I got the basic bar the way I wanted it, it was pretty bland in color and in smell. Perfect. So then I was able to start playing with the scents and colors.

There are essential oils that can be used, but there are also synthetic oils that mimic certain smells (Turkish mocha, for instance). I played with them all. But you can’t just add these new oils. If you use any extra oils, you need to re-calculate the balance of lye and water.

Then there are colors. There are a lot of things you can use to add color, but I like ground mica. It is UV safe and it doesn’t affect the saponification reaction. It just adds color. There are thousands of different micas to give your soap exactly the color you want.

We ended up building a soap laboratory in the Garnet School to keep all of the supplies, plus a soap curing machine. That’s just a fancy name for a cabinet with fans. You can cure soap at home just by leaving it exposed to air.

And that soap business I mentioned. I ended up making soap for the same restaurant/butchery that gives us the food scraps. The soaps were branded for the restaurant, and included the story saying where the fat came from. Sales were brisk.

We had a lot of fun with the naming the soaps: Lavender Love, Winter Forest, Chai Chai Rodriguez, Banana Fanna Fofanna, Chocolate DO NOT EAT!, and Spit. I even made a batch where I took cut-offs from a bunch of different batches, mixed it together and called it “Fruitcake”.

If you want to learn more about soap, and take home your own six-bar loaf, come to our Soapmaking class. You’ll mix up your own batch with scents from our laboratory, pour it in the mold and take it home. The next day, you’ll release it from the mold and cut it into bars. They’ll need to “cure” for a few weeks before you use them, but I’ll bet you’ll be making your next batch long before that!