Common soap bars are a 19th century invention, but soap was used in the textile industry and medicinally for at least the last 5000 years. Some snapshots of the role soap plays in our lives make for a fascinating tour back through time. Archaeological evidence of soap was found in Babylonian clay containers dated at 2800 B. C. Inscriptions on the containers state that the product was made from fats boiled with ashes. The product thus produced was not necessarily used to wash the body; it might have been used to wash wool used in textile manufacture. The Ebers papyrus, 1500 B. C.
refers to medicinal use of soap for skin diseases. These texts suggest that both animal and vegetable fats were combined with alkaline salts to make a substance used for treating sores as well as washing. Thanks to the aqueducts, bathing became convenient and popular in Roman times; however, it is believed that people in those days cleaned their bodies by rubbing abrasive substances, like sand or pumice, over the skin and then scrapping off the grime and gravel with sticks. This exfoliation ritual might have been followed by luxuriating in scented baths and then massage with perfumed oils.
Scents were added to baths as disinfectants and to lotions for aesthetic purposes. We will recall that the word “lavender” comes from the Latin word lavare, meaning “to wash” but lavare might originally have been a medical term for cleansing wounds. Thus, while lavender was added to water for its value in maintaining hygiene in communal baths, its use in soaps was most likely determined by medical demands. Regardless of the end uses of soap, soap was popular throughout the Roman Empire. An entire soap factory was discovered in the ruins of Pompeii, one of the cities destroyed by the volcanic eruption of Mt.
Vesuvius in 79 A. D. We do not know whether this factory supplied the textile industry or apothecaries and physicians. We do know that the dual use of soap for commercial and soap for personal use has existed for millennia. The famous Greek physician Galen recommended washing with soap as a preventative measure for certain diseases, especially diseases of the skin. Historically, soap was not used to promote luster to the skin or hair nor was it used to impart fragrance. These aesthetic aims were achieved with bath scents and body lotions.
Thus, to the extent that soap was used on an individual basis, it was for medical and hygienic purposes, not bathing or beauty. Which came first, a decline in bathing habits or the plague, is not clear, but hundreds of years ago, bath houses were closed because their use was associated with the rampant spread of the Black Death. We might recall that similar public health measures were implemented more recently when the AIDS epidemic was linked to bath houses! With the demise of public bath houses, bathing and washing became a luxury only the rich could enjoy.
However, soap making remained an important activity for both the textile industry and apothecaries. People who carried on the arduous work of making soaps for personal use tended also to make candles since some of the same raw materials are used in both products. In short, throughout history, soap use for personal hygiene was medically motivated. However, short-cuts in manufacturing techniques achieved in the 19th century resulted in two important developments: First, a new process, using sodium hydroxide, made for a hard rather than liquid product that was easier to store and ship.
Second, soap became easier and cheaper to make and thus became more affordable and popular. The result was entirely predictable: public hygiene in more affluent areas of the world experienced a quantum leap. Soap: A product that when used with water decreases surface tension so as to loosen unwanted particles, emulsify grease, and absorb dirt and grime into foam. Soap making is a serious occupation requiring some understanding of chemistry. Traditionally, the manufacturing of soap was a lengthy process with a considerable number of unpredictable stages.
We can appreciate the difficulties if we realize that soap results from a chemical reaction between an acid and base that causes “saponification” to occur. Typically, the acid portion of soap comes from a fat, either an animal or a vegetable fat. The alkali or base is the more precarious component because it was usually made from ashes, basically any ash from any burned organic material, but usually from wood used in cooking fires. When water drips on the ash, a brown liquid forms whose exact chemical properties would have been difficult to judge prior to the advent of pH testing devices. “Saponification” is another word of Latin origin.
It refers to Sapo Hill, which according to legend is a place above the Tiber where animal sacrifices were made though some think Mount Sappo was a place in Greece. Women washing their clothes in the river below this place found that less effort was needed to clean them where there was run-off from the temple on the hill. What had happened was that fat had boiled over into the fires and remained in the ashes. When the residues of the burnt offerings were exposed to rain water, the mixture of fat and ashes formed a “natural” soap that traveled into the river below where the sacrifices had been performed.
When a base reacts with a fat or oil, fatty acids are separated from the glycerin and the sodium or potassium component of the alkali bonds with the fatty acids. The product formed by the sodium or potassium and the fatty acids is a salt. Technically speaking, soap is a salt. Glycerin (also called glycerol) is a by-product that also has cleansing properties. It is hydroscopic, i. e. moisturizing because it attracts water from the air. As can be deduced by the notes in the table, soap should have a neutral pH. It should not burn the skin. It should also be made from pure ingredients so let’s discuss the ingredients.
Most inexpensive soaps are by-products of the meat packing industry. There are, however, a large number of reasons for preferring vegetable-based soaps over animal ones, not the least of which is that toxins, including synthetic hormones used to bulk up animals, tend to accumulate in fat tissue. If this were not a cogent enough argument, it is fairly easy to demonstrate that animal fats tend to clog pores more than vegetable oils. Even going back many centuries, soaps made from vegetable oils, like Castile soap, were regarded as superior to those made from lard.
Animal fat has to be “rendered” or purified. This involves cooking and odor. Meat has to be separated from the fat. This is usually done by heating the fat so that the cracklings separate. The meat looks like it has been cooked, which, of course, it has. The meat must be removed. Sometimes, water has to be added so that it absorbs the impurities. Then, the “soup” has to cooled, usually slowly, so that the fat separates and rises to the top while the heavier parts sink. The fat is then skimmed off. If the fat still has odor and impurities, the process has to be repeated.