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A Brief History of Soap and its Impact on the Environment

Ingrid Naiman

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.

Archaelogical 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.

lavender

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.

 

The Soap Making Process

In the table below, the basics of soap manufacture are summarized, but real soap making is either an art or a science. Trial and error can be very frustrating. Adventurous people will want to have a recipe with specific instructions and proportions. They will also need a bit of equipment.

Acid
Alkali
Normal pH is 7.0
Water should be 7.0
Acids are chemicals with a pH lower than "neutral". An acid may be mild or extremely caustic. Alkaline substances have a pH higher than 7.0. They may be mild or corrosive.
The type of acid used to make soap is a fatty acid, either from animal fat or vegetable oil. The alkali used to cause the chemical reaction with the fatty acids is either made from potash (lye water) or sodium hydroxide.
Saponification
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.

Animal Fat:

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.

Vegetable Oils:

In Spain, there was a tradition of fine soap making, called Castile because of the place name. These soaps used mainly olive oil. Today, coconut oil, sometimes called coconut butter, is used in many soaps because it lathers nicely and is almost odorless. However, almost any vegetable oil can be used. The more common ones are almond, avocado, jojoba, palm, and shea butter.

Lye Water:

As noted, this is made by pouring or dripping water over ashes. Different woods or other organic materials produce variations in color. Soft water, i.e., rain or spring water, should be used. If the solution does not have a high enough pH, it needs to be poured over more ash. If it is too corrosive, more water needs to be added. This is a time consuming process that requires burning one's own organic materials over an open fire or in a cast iron pot. If a feather dissolves in the lye, the pH is probably about right. Some try floating eggs or potatoes in the brew. These objects should float so that half their mass is below the water line.

This kind of base will make a soft soap, not a hard soap.

Caustic Soda:

Sodium hydroxide is a nasty chemical that requires special handling, like safety goggles and gloves. It was introduced in the 19th century by French chemist named Nicolas Leblanc (1742-1806) and improved by a Belgian chemist, Ernest Solvay (1836-1922), who changed the nature of the soap and impacted the industry radically. Basically, the newer methods substituted sodium hydroxide for the lye water made from potash. The result was a hard soap that was easy to store and ship. Soap making moved from the farm to industrial manufacturers who realized huge profits from the recycling of animal fats into commercially viable cakes that were easy to sell.

Other Ingredients:

As everyone knows, there can be a lot of ingredients in soap: chemical stabilizers, preservatives, fragrances, vitamins, seaweed, corn, oatmeal, pumice, aloe, dyes, milk, fruit or berries, cucumbers or carrots or other vegetables, exotic oils, beeswax, herbs and flowers . . . Each ingredient changes the chemistry of the bar of soap. Let's see how clear I can be. Milk, from goats or other animals, counts towards the acid (and water) component of the soap. Aloe gel counts towards the base component and enhances the disinfecting properties of the soap.

Intuitive people as well as those who are cutting edge in new ecological developments must realize that each constituent not only has to go through some process to prepare it for use in the soap but each one changes the pH of the soap—and our environment—because even if run-off today does not start in a temple where animal sacrifices are performed, it starts with animal sacrifice and ends up laced with antibiotics and derivatives of the petrochemical industry that eventually end up in sewage and septic systems.

 

Commercial Soap

Dial is a good example of a commercial soap. It is produced by Armour, but it is a truly distant cousin of Borax, a cleanser that went into production after the discovery of vast deposits of borax in Death Valley during the Gold Rush in 1880. The Armour family went into the soap business eight years later. Then, it produced a scouring pad for aluminum cookware called Brillo (1913). Purex began in a garage in Los Angeles in 1922. Enter the meatpacking industry: Dial is introduced in 1948 as the first antibacterial soap. The ad campaign is enormous and promises 24-hour protection from bacteria-causing odors. Next comes Vienna sausage in aluminum containers . . . beginning to see a flash back of your childhood?

Let me continue. In 1988, while the former host of "Death Valley Days" is sitting in the Oval Office, the rights to market 20-mule team of Boraxo are acquired. Next come the first microwave cup meals. A year later, Liquid Dial is introduced. It rings up a million in sales in the first 10 weeks on the market. The deal with WalMart takes another decade to pull together. In the meantime, the company has split and spun off some products and acquired new ones.

 

Soap versus Detergent

A detergent is a synthetic imitation of a soap, i.e. a laundering agent made from chemicals. Detergents were developed in Germany in 1916. They are not just "imitation soaps." Detergents are different from soaps in that they do not combine with natural mineral salts in water and do not form scum. Unlike real soap, detergents work in cold water and with salt water. Soap and detergent have similar capacities to emulsify fats and oils and hold dirt, but from this point on, they are significantly different due to the presence of surfactants and additives, such as whitening agents. The list of the chemicals used to produce these detergent effects is hair raising.

Beginning around 1960, it was noted that there was more foam on rivers and that sewage treatment facilities were encountering serious problems, including that water foamed when it came out of the tap, this due to the fact that propylene-based alkyl benzene sulphonates are not completely degraded by the bacteria naturally present in effluents. It is not for me to try to explain the chemistry of all that started to go wrong, but merely to note that the correction being sought was to increase use of proteolytic enzymes to aid the breakdown of materials that were not readily "bio-degradable." The ramifications of this are almost too far-reaching to imagine.

 

Summary

It is not possible to do justice to soap's fascinating history in a single web page, but this overview ought to give many people incentive to reflect on the many, many soap products they use daily: liquid soap, bar soap, shampoo, liquid and powdered dishwasher and laundry detergents, and a host specialty cleaning products, all of which have a major impact on health and the environment.

Fortunately, however, there is a resurgence of interest in cottage industry soap manufacturing in which both the hygienic and aesthetic demands of the most fastidious connoisseur can be satisfied.

More on Soap:

Kitchen Doctor

 

 


 
 


Poulsbo, Washington