People have been using various
cleansing agents since ancient times because water itself does not readily
get rid of dirt and grease. Water has high surface tension, which causes
it to run off greasy areas or stay there without penetrating. Only when
a cleansing agent that lowers surface tension is added, can water penetrate.
The Babylonians added alkaline
plant ash (potash) to water. Other primitive purifying agents were fine
clay that easily absorbs impurities from oil and fat, and trees and plants
containing a soapy substance called saponin. The Old Testament mentions
a cleansing product made of tree bark ashes alone. Soap itself was probably
first made in the Nile valley by Phoenicians. Around 600 BC they carried
the knowledge to the Mediterranean coasts. In the 1st century AD, Roman
women used various forms of hard and soft soaps, which contained dye, to
cleanse and impart brilliant colors to the hair. By the 8th century, soapmaking
became common in Italy and Spain and most soap was made from goat’s fat
and beechwood ashes. In the 13th century, the soap industry was introduced
from Italy to France. The Spaniards had used vegetable oils such as olive
oil as early as 700 AD but the French were the ones responsible for further
development of this method and for introducing it to the Britons.
By the end of 18th century
a number of changes took place, which transformed the soap industry from
a small domestic endeavor to a fully-grown business all over Europe. In
1783 the Swedish chemist Carl Wilhelm Scheele accidentally discovered a
sweet-tasting substance, now known as glycerin, by boiling olive oil with
lead oxide. In 1791 the French chemist Nicolas Leblanc discovered that
alkali caustic soda could be made from common salt - a plentiful
raw material - so manufacturers no longer depended on potash.
In the early 19th century
other oils beside olive oil became more easily available. Coconut oil,
palm oil, sesame oil, and soybean oil were imported from Africa, Southeast
Asia and China. Social changes in the 19the century and the discovery of
oleic and stearic acids further stimulated soap manufacture.
Today’s methods still follow
ancient principles although modern equipment allows the process to be completed
in 15 minutes instead of several days. The treatment of oil or fat with
alkali (saponification) is the first stage in making of all types of “washing”
soap. This reaction produces sodium salts of stearic, palmitic and oleic
acids. After saponification the soap contains about 30% water - for making
the denser toilet soaps this has to be reduced to about 12%. Then various
refinements such as perfumes, essential oils, preservatives and coloring
materials are added and thoroughly mixed. The molten soap is then cooled
and cut to size.
The fatty acids required
for soap making are supplied by tallow (animal fat), grease, fish oils,
and various vegetable oils. Tallow used in soap making ranges from the
cheapest grades, recovered from garbage and used for cheaper soaps, to
the best edible grades, used for fine toilet soaps. To increase solubility
and to provide satisfactory lathering of soap, different oils and fats
are usually mixed and combined. A fine toilet soap made of high-grade olive
oil is known as castile soap.
Between Soaps and Detergents
Soaps have a number of disadvantages
as cleansing agents. They do not work in acid water and, most importantly,
they do not work well in hard water. The soap reacts with calcium and magnesium
salts to form the familiar “scum” that leaves insoluble rings on bathtubs.
Moreover, the availability of the raw materials for making soap varies
unpredictably. For these reasons manufacturers began looking in the late
1940s for a new type of synthetic detergent. Today, a majority of mass-produced
soaps, shower gels, shampoos and other cleansing agents are based on synthetic
The first synthetic detergents
to be made on a large scale were based on products of the distillation
of crude oil - at the time cheap and readily available raw material. But
early ABS detergents (alkylbenzenesulfonic acid) had an important defect.
They contained branched chain molecules that made them biologically “hard”,
or nondegradable, which meant that the bacteria in sewage treatment plants
did not easily break them down. These were replaced by degradable detergents
(linear alkyl sulfonates, LAS).
Even the biodegradable detergents
are not free from faults. In addition to the LAS, which is the cleansing
agent, or surfactant, many other substances are added, such as builders,
bleaches, conditioners, optical brighteners and enzymes. A builder prevents
the formation of insoluble compounds in hard water. A typical one is sodium
tripolyphosphate, which breaks down into phosphates and can lead to an
excess growth of algae and other water plants in rivers and lakes. In the
late 1960s a search began for a replacement for these phosphates. Several
alternatives were developed, but all proved to have worse side effects
than the phosphates.
Future of Soap Making
As we are becoming more aware
of health and environmental problems related to the use of synthetic detergents,
we feel the need for a change. Sometimes, the change means going back to
time-tested yet forgotten practices. Throughout the centuries, the intrinsic
part of soap making was use of aromatic oils and various plants with healing
properties. Bathing was a ritual created to cleanse body and soul, to nourish
and soothe, to elevate the spirit. It was never about dirt, so to speak.
In our frenzy to wash away every single impurity and germ we forgot the
essence of self-care.
Today, soap makers are looking
for inspiration in the works of ancient herbalists. These old recipes are
then successfully combined with the latest scientific discoveries that
help to protect our skin and environment.
Fragrances are changing
too. More natural and distinctive, they follow the principles of aromatherapy.
A smaller, artisan based, production of fine soaps allows a more creative
approach in every respect. A unique blend of scent, look and feel is reaching
new heights in today’s soap making and this trend will continue in the
years to come.