While attending the Black Powder Rendezvous at Old Greenville, I bought a bar of old fashioned lye soap. You know, the kind grandma used to make in an old kettle outside in the yard. It would clean anything and could wash the skin right off your bones. Anyway, I bought a bar and decided to actually use it.
That got me to thinking. Yes, I know that comes at great risk, but I was curious about soap. We all use it every day. We use it to clean all sorts of things, from our hands to our hair, our dishes to our cars. But did you ever ask "What is soap?" "Why does soap clean?"
Well, soap has been made for well over 2,000 years following basically the same recipe. Basic soap has three ingredients. Lye (which is a base), water (to carry the lye), and a fat or oil (which is an acid). When a base mixes with an acid, a salt is formed. The base and the acid are no longer there, but have reacted chemically to become the salt. Yes, soap is actually a salt. Whoda thunkit?
The chemical process of lye mixing with fat or oil is called saponification. Specifically, according to Webster, saponification is "to hydrolyze (a fat) with alkali to form a soap and glycerol." Remember glycerol...we'll come back to that in a bit.
So why does soap work? Well, we all know that oil and water don't mix. If all dirt were just dirt, we wouldn't need soap. Dirt is easily washed away with water. However, oily substances cling to things tightly and when you put water on it, the water just slides right by it without grabbing it at all. Just ask any mechanic who has gotten their hands all greasy. Water just won't cut it. Well, saponification changes the molecules in the oil or fat so that one end of the molecule bonds nicely to oil or grease, while the other end of the molecule bonds nicely to water. The soap allows the oily "dirt" to bond to the water we wash with and carry it away.
Glycerol. Remember I told you we would come back to it... Well, glycerol is naturally produced during saponification. Glycerol is a great thing. It is a natural humectant. A humectant is a substance that attracts moisture. Having glycerin on your skin helps keep it from drying out. By attracting water molecules to your skin, your skin stays moisturized and supple. Home made soap is roughly about 10% pure glycerol. Avon sells a fine product called MOISTURE THERAPY Ultra Skin Renewal Body Lotion
(876-851). A 13.5 fl oz bottle sells for $10. Guess what it is? Water and glycerin, followed by a bunch of chemicals I can't pronounce. I did recognize "urea" in the list...ewww. (Go here: http://shop.avon.com/shop/product.aspx?pf_id=38607, then click on "ingredients" under the picture.)
So what about commercial soap? Well, all soap is lye soap. Period. When they say their soap has no lye, they are not lying (no pun intended). Because in the saponification process, lye undergoes the chemical reaction with the acid and is no longer lye. So, technically, even home made lye soap has no lye in it...anymore. The down side of commercial soaps is that they add and take away. They usually add perfumes and preservatives. These may or may not be good for you, especially if you suffer from allergies. Secondly, they usually remove most of the glycerin. Why? Because glycerin is valuable, much more valuable than soap. They can remove the glycerin and sell it or use it in their high end (expensive) products and thereby sell you the soap much more cheaply.
So, it breaks down like this: Home made soap + chemicals + perfumes - glycerin = commercial soap
Soap can be made from almost any oil or fat. Grandma rendered (boiled) lard from pork, beef, or even deer to use in making soap. They burned hardwood in the stove and used the ashes to make lye water by running rainwater through the ashes. Today, you could make soap from shortening, lard, or even vegetable oil. My personal favorite to date is from Soybean Oil. (No animals were harmed in the making of this soap.) So what do commercial soap makers use? Well, let me just say that most soap companies are owned by companies that also own meat packing companies. Efficiency (aka profit) is from not letting ANYTHING go to waste.
I think it is neat to know exactly where my soap came from and how it was made and how it cleans my skin, while effectively protecting my skin with healthy glycerin.