My apprentice, Ellynor Redpath, is full of ideas. Most of the time, her brilliant notions involve skills well beyond my own (I can barely manage a straight stitch), but this one? This one was dangerously right up my alley: playing with caustic materials. Seriously, what’s the worst that could happen when you deliberately handle a substance that dissolves flesh? Exactly.
What Had Happened Was… The Diaper Rabbit Hole
Ellynor and I were deep in discussion about one of her latest research projects when, as often happens, we tumbled down a very specific rabbit hole. We went from discussing baby garments in Elizabethan England straight into the vital, if somewhat less glamorous, topic of how one would actually clean those garments. A logical progression, of course, given my research focus!
Our quest for spotless linen quickly narrowed down to two period-appropriate contenders: the simple elegance of sun bleaching and the mysterious power of black soap. Naturally, we decided to field-test both. Ellynor’s mission was to furnish the linens, mine was to make the soap.
Sun Bleaching: The Simple Life
This method is delightfully straightforward and self-explanatory. You soak your linen in hot or boiling water, give it a thorough beating with a laundry beater (more on that particular tool another day!), and then lay it outside in the hot sun. It’s truly a low-stress operation.
Black Soap: It’s Made of WHAT?
Now, here’s where the fun (and the potential chemical burns) begin. Black soap is a mixture of lye (also known as caustic potash or potassium hydroxide) and animal fat. Yum.
The theory is simple: Take hardwood ash, steep it for several hours in rainwater, and slowly filter the resulting liquor, yielding your lye. This caustic solution is then mixed with a fat, like beef tallow or lard, and boiled until it forms a thick, jelly-like soap. It earns its charming moniker, “black soap,” because the solution is dark from residual wood ash.
I have a wood-burning stove, which means I have a steady supply of ash—the key ingredient! I may have neglected the rainwater collection bucket, but I had modern distilled water, which is arguably even purer than what a 16th-century peasant could manage. What could go wrong?
Things Did Not Go According to Plan (An Immediate Disaster)
My first attempt at lye production was, in a word, a catastrophe. Granted, I didn’t melt the flesh off my body, so maybe catastrophe is a hyperbole, but still… Let’s break it down so you can avoid my rookie errors.
- The Vessel: My husband, bless him, drilled neat drainage holes into the bottom of a small wooden bucket—my lye leaching vessel.
- The Filter: I lined the bottom with burlap to strain the ash, then poured in about a half-cup of ash.
- The Strain: I poured my fancy distilled water over it and let the ‘lye’ slowly strain through. I repeated this three times.
The Egg Test of Failure
The moment of truth: The Egg Test. This is the ancient litmus test where you drop an egg into the solution. If a portion of the egg floats above the solution, you have lye, and the amount floating tells you the strength.
My egg didn’t float. It didn’t bob. It performed a rapid, unceremonious, rock-like sink straight to the bottom. Conclusion? I was left with a cup of very expensive, very dirty water.
Take 2: Steeping and Hoping
Since three strains failed to produce the necessary caustic strength, I decided to move the whole mess—the ash-filled burlap and the dirty water—into a cast iron pot with a lid and let it steep overnight. That should do it, I thought, surely giving the water enough time to dissolve the potassium carbonate.
WRONG.
My second attempt also failed. I clearly have a serious problem with my ash-to-water ratio, or perhaps my high-minded distilled water simply isn’t cutting it.
Take 3: Next Steps
Thanks to chilly evenings, I am replenishing my wood ash supply and praying for rain to collect rain water. Once I have a sufficient amount of both, or at minimum the ash, I will try again, this time with a 2:1 ratio of water to ash. Oh, and try heating up the water first, which I did not do before, but read in my notes after.
Stay tuned, because the quest for black soap continues! I’ll keep you updated on the next (potentially explosive) attempt. And for those of you who want the full, footnoted, and incredibly detailed breakdown of this entire saponification adventure, a paper on this experiment is currently in the works and will be published soon!