1. A cleansing agent, manufactured in bars, granules, flakes, or liquid form, made from a mixture of the sodium salts of various fatty acids of natural oils and fats.
2. A metallic salt of a fatty acid, as of aluminum or iron.
Soap is fascinating stuff. It is actually a salt that foams! This crystalline nature of soap allows it to be made clear as glass when boiled in alcohol with sugars. (Like Soapy Hollow glycerin soaps.) A salt is what you get when you mix an acid and a base together. The acids and bases neutralize each other and a salt forms in the process. Soap is made from acidic oils and an alkaline solution. Oil and alkali must be in balance to make the perfect bar of soap.
The U.S. Food and Drug Administration defines soap as: “is any product where the bulk of the nonvolatile matter in the product consists of an alkali salt of fatty acids and the product’s detergent properties are due to the alkali-fatty acid compounds, and the product is labeled, sold, and represented solely as soap” [21 CFR 701.20].
Interestingly enough, if a product intended to cleanse the human body does not meet all the criteria for soap, as listed above, it is either a cosmetic or a drug. For example, many clear soaps are actually sodium laurel sulfate, which is a petrochemical detergent. Those are classified as a cosmetic. Soaps that that makes a claim like “deoderant” or “cures acne” are classified as drugs, and not as soap.
I’ll write more later on the difference between soaps and detergents. I’ll also be talking about how new proposals on the way to the congressional floor will impact businesses and consumers of boutique and artisan soap.