Just Plain Soap
by Richard M. Hamner, PhD
Have you ever wondered just what is in a bar of soap? Conversely, do you wonder what should be in your soap that isn't? Most don't know how soap is made or what makes one brand better than another. It is with soap—as it is with most things—when you understand the process behind how it is made, you can make smarter choices about what is best for you.
Soap of old was usually made by taking lye and rendered lard and mixing it in a big iron wash pot. Called lye soap, it had a reputation for being harsh. An old saying associated with it was, "it doesn't stop at the dirt."
Technically, soap is still made using the same chemical reaction. The main differences between modern and old soaps are use of purer oils and lye, a higher understanding of soap chemistry, and a more precise standard of weights and measures.
Technically, there are other differences, most of which were made to more effectively market and sell these products.
THE CHEMISTRY OF CLEAN
Soap making is based on a natural chemical reaction called saponification. Oils are reacted with a strong alkali or caustic, resulting in soap and glycerin. Fats and oils are all triglycerides, which are made up of a glyceride ion attached to three fatty acid chains. When the caustic is mixed with triglycerides, the fatty acids break loose from the glyceride ion and join with the sodium in sodium hydroxide, forming soap. The glyceride ion joins with the hydroxide of sodium hydroxide, turning it into glycerin.
IN A NUTSHELL: OILS + CAUSTIC YIELDS SOAP + GLYCERIN
GROCERY STORE SOAP
Nearly all soaps found in grocery stores contain 80% tallow and 20% coconut oil. Tallow comes from beef fat and coconut oil comes from the coconut palm. These oils are reacted with caustic soda. While still hot, the glycerin is immediately removed and the resulting soap is cooled and dried. Since most of the world's major soap makers use this 80/20 base, the only real differences among them are fragrances, colorants, and other additives.
The following is a list of additives use in typical bar soap formulas: fragrances and perfumes, colorants and whiteners (such as titanium dioxide), antioxidants (BHT, etc.), preservatives and sequesterants (EDTA, DTPA, etc.), deodorants and antibacterials (like Triclosan), skin-feel additives (such as polyacrylates), lather stabilizers (cocoamides), fillers like starch, and salts to harden the bar.
Notice that none of these have anything to do with getting you clean or caring for your skin. These are ingredients dictated by marketing departments to make the bar look, feel, and smell a certain way. These ingredients may also give you a headache, make you sneeze, or cause your skin to itch.
WHAT ABOUT THE GLYCERIN?
Soap making naturally produces glycerin, a humectant or moisture retainer, making it a natural skin moisturizer. Curiously, most soap at the grocery store doesn't list glycerin as an ingredient, because it has been removed. Unfortunately, soap without glycerin is more drying to your skin.
Why has the glycerin been removed from nearly all mass-produced soap? It's because glycerin can be sold as a separate commodity. It's used in pharmaceuticals, cosmetics, food products, and cellophane—with greater financial gain than leaving it in the soap.
Another point of confusion: Glycerin soap, by itself, is not transparent. It is made clear by adding certain alcohols and sugars like sorbitol. Pure soap is dissolved in them, resolidified, and the change in the molecular structure allows the light to come through. Pure soap with glycerin remains opaque. Further, some transparent bars are not even soap. Triethanolamine (TEA) is an example of a surfactant—a synthetic detergent—that is also transparent and used in some cleansing bars, but it is not soap.
SOAP VS. DETERGENT
Next time you are in the grocery store, review the ingredient list of a "beauty bar," "deodorant bar", or "body wash." If it contains "sodium cocoyl isethionate" or "sodium lauryl sulfate," then what you are holding is synthetic detergent, not soap.
Most soaps are really not soap at all. Many are detergents with additives and no glycerin. What your skin needs is the opposite: pure, natural soap which has no additives and lots of moisturizing glycerin. Read labels and try to choose a bar that cleans and moisturizes—the old-fashioned way.