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.
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.
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 a 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 was enormous and promised
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" was
sitting in the Oval Office, the rights to market 20-mule
team of Boraxo were acquired. Next came 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 took another decade
to pull together. In the meantime, the company 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
to 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 of 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.
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