Rebecca Widds wrote:Backed, and used the opportunity to grab a hard copy of A Year in an Off-Grid Kitchen as well. That book gave me far too much joy to just live on my Kindle! Congratulations and good luck, Kate!
Jennifer Kleffner wrote:Long time soap maker here. This is a cut and paste from Dr. Dunn, who wrote the Scientific Soapmaking book (he's a chemistry professor who uses soap making to teach his students chemistry). Highly recommend his books. Short answer, no.
What was the question?
Kevin Dunn I'll weigh in on two points here. As many have pointed out, natural does not mean good or safe. We have been hurt and killed by nature since the dawn of time. Tornados, rattlesnakes, gizzly bears, and hemlock are all natural. The dictionary defines "natural" with several meanings, but none of them equal "good" or "safe." Can you find sodium hydroxide lying around without any human intervention in making it? No. The closest you can come is "trona," the mineral from which baking soda and washing soda are made (by humans). There is no official governmentally sanctioned definition of "natural" as used in commerce. Therefore, anyone can legally claim that any product is natural. The word just doesn't mean what people want it to mean.
Kevin Dunn The second point is that the active ingredient in wood ashes is potassium carbonate. If you burn sea plants, you get sodium carbonate. Yes, you can make soap with either of these, but for a hard bar soap, you want sodium hydroxide. The traditional way to get the hydroxide is to react wood ashes with lime (calcium hydroxide). My book, Caveman Chemistry documents the history of the alkali industry, and has several projects on making alkali from ashes and lime. Reacting wood ash with calcium hydroxide produces potassium hydroxide. To get sodium soap from potassium hydroxide, you add salt once the cook is done. Sodium soaps are less soluble than potassium soaps, so they float to the top, where you can skim them off. Making soap from wood ashes is a challenging, but rewarding project. It is part of the "Level 3 (master)" certification for the HSCG.
Kevin Dunn 1000 pounds of wood leaves about 5 pounds of ash, from which about 1 pound of potash (potassium carbonate) can be extracted.