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