Good clean fun: how to make cold-pressed soap at home

I wonder how many of us have thought about the provenance of soap. I considered it in the shower once. If you’d told me a few days ago that it’s dug from the bottom of the great soap mines of Antarctica I’d probably have believed you.

Twenty-four years of unforgivable incuriosity ended when I learned that my elder sister had been cooking up soap in her bathroom. She lives in Canada, so I was unable to sample it, which, given the amount of caustic soda she said was involved, might have been for the best. She didn’t burn a hole through the bottom of the bathtub though, and I thought it was about time I figured out how soap, that odd, waxy brick of cleanliness, came to be. And, in truth, I’d also come to feel that if I was going to use soap to lather up my flesh, I owed it the dignity of knowing more about it. Some people, out of guilty respect, like to know the name of the farm from which their meat comes. Since being used to wash a stranger is probably even more unpleasant than being eaten, I figured that it was about time I saw where soap came from.

And so to the Little Soap Company, where I’m being taught to make my own soap. We’re in a sparkling kitchen in their HQ, a pretty, stone-walled former butcher’s shop in the village of Broadway, Worcestershire. Broadway is one of those sparkling, golden Cotswolds villages that look like they’re secretly scrubbed mercilessly by an army of house elves just before the tourists arrive each morning. 

Emma Heathcote-James

My teacher today is Emma Heathcote-James, a professional soapstress and the company’s owner. “Art and chemistry come together in soapmaking,” she tells me. Soap, I finally learn, is made by saponification: the chemical process triggered by adding lye (diluted caustic soda, aka sodium hydroxide) to fat (in the form of oil), with fragrant additions as per the maker’s taste. The product of saponification? Soap. God knows how humanity stumbled across this process.

By way of demonstration, Emma whips up a mixture that, once cooled, will become an apricot-scented bar of soap with eucalyptus and peppermint essential oils. And poppyseed, and a feathered green pattern. She magics it all up by combining what looks to my uneducated eye like three varieties of gunk, a couple of clear liquids, and a sprinkle of green powder, caressed with a knife to create the feathering. 

As the more-than-the-sum-of-its-parts stakes go, this is up there with God’s creation of Adam from clay. I’m still trying to memorise what she’s done when she asks me to have a go. Gulp. We start with the gunks: one tub of coconut oil and another of palm oil (“Sustainable!”, she pre-empts). In the summer heat, each has the consistency of gelatinous mashed potato. It is my solemn responsibility to plop 112g of one and 140g of the other into a saucepan. Horrible pale blobs stare up at me from the bottom of the pan. With some relief, I hack them up with a knife so that they melt quicker on the hob.

While this awful concoction simmers away, I weigh out 198g of olive oil, which I’ll use to cool the mixture on the hob once it’s melted. Next, we finish the lye. Caustic soda, star of that time you had to unclog your kitchen sink, is a white powder and, like other white powders, has a way of energising whatever it’s put into. Having donned gloves and goggles, I scoop some out of a skull-and-crossbones labelled bucket and tip it into the water.

“Don’t breathe the fumes,” says Emma, as I breathe the fumes. Beware: sodium hydroxide poisoning can cause, among plenty of other ailments, breathing difficulty, throat swelling, diarrhoea, vomiting, drooling, vision loss … I stop breathing the fumes. The vapour is warm to the hand, and by now the coconut and palm oil have melted into each other.

When both pans have cooled to around 43C (110F), we pour the contents of one into the other. Without the caustic soda, this would simply be a lava lamp-ish meeting of oil and water, which, like shy teenagers at a school disco, are usually reluctant to mix – until you add a stimulant. The caustic soda. This encourages the oil and water to combine, provided that you whisk them thoroughly.

Initially, it’s all clear liquid with the consistency, thereabouts, of water. As I whisk, it slowly begins to thicken, until it’s possible to leave traces of drizzle on the surface – the stage that is called “trace”. At this point, it’s ready for the essential oils.

“What are your favourite essential oils?” Emma asks. I do not know what my favourite essential oils are. Rather embarrassingly, I do not know what an “essential oil” is. She guides me to English lavender and rose geranium, with some jojoba oil thrown in, and it all ends up in the pan. I add some oats to give it some more texture, we pour it into a wooden mould lined with greaseproof paper alongside the soap Emma made earlier, and we leave it to set. 

For now, it’s porridge-like and sweet-smelling. When it’s cured in four weeks’ time, it should, despite my inexperience and clumsiness, make a passable soap – albeit a unique one. “Soapmaking is like baking a cake,” Emma says. “You can give people exactly the same ingredients, and they’ll all come up with something different.”

That’s it. That’s soapmaking. Never again will I have to buy presents for girlfriends or my mother: all I need is some oil, water, stuff that smells nice and caustic soda (which, yes, you can buy online: Emma recommends the Soap Kitchen for all your caustic soda needs). I carry the soaps home in a sturdy cardboard box, which I rest on my lap while I wait for the train. I can feel the warmth of the chemical reaction on my thighs.

All that remains is to cut the soap up in the morning, wait a month for it to cure, wrap up some for myself and then relentlessly dole out the rest as presents. If I know you and you’ve got a birthday coming up, well, forget you ever read this.

Little Soap Company products are stocked in supermarkets including Waitrose, Sainsbury’s and Tesco, and Broadway’s Little Soap School teaches three days a week. Book classes and buy soaps at littlesoapcompany.co.uk