The History of Soapmaking

It is impossible to say who invented soapmaking and when soap was first made. Soap had been used by humans for thousands of years. Interestingly, soap was first used to clean fabrics and pots. It was not until much later that people began using it to clean themselves. Before the development of soap, it is likely that people used plants containing saponins for cleaning. The earliest known use of a natural soap-like substance was the Reeta (Sapindus) nut, which had been used by Indians since antiquity. Other plants that have been used are the Soapwort (Saponaria officinalis), many species of Yucca, Soap Lily (Chlorogalum pomeridianum), and the Horse Chestnut (Aesculus hippocastanum)(1). Even today, many people throughout the world employ these plants as cleansers.

Reeta nut (Soap nut)

 A popular myth claims that soap was first discovered and takes its name from Mount Sapo a location near Rome. It is said that animals were sacrificed to the Gods on this mountain and legend has it that the animal fat and wood ashes from the braziers would be washed into the Tiber River during rain storms. The animal fat and ashes would combine to create a soap-like substance that would stick to the sides of the river. When women in the area came to wash their clothing in the river, they noticed that the soap-like substance made their wash cleaner with less effort. However, the location of Mount Sapo is unknown, as is the source of the "ancient Roman legend" to which this tale is typically credited.

It is believed that a soap-like was first invented by the ancient Babylonians at least 5000 years ago. The first evidence of this substance was found during excavation of ancient Babylon. The soap-like substance was found in clay cylinders and dates back to around 2800 BC (2). A clay tablet from Babylon dating to around 2200 BC records a formula of water, alkali, and cassia oil to make soap. This soap is thought to have been used in both cleaning wool and cloth in textile manufacture and also used medicinally.

The ancient Egyptians are also known to have made soap. A medical document, the Ebers papyrus, dating to around 1550 BC states that soap was made by combining animal and vegetable oils with an alkaline salt. The soap was used for treating skin diseases and for washing.

Ebers Papyrus

It is also evident that soap was used by the Roman empire. Pliny the Elder recorded in Historia Naturalis (around 70 AD) the manufacture of soap using tallow (fat) and wood ashes (3). He states that the soap was used as a pomade for hair. This book is also the first appearance of the word sapo, Latin for soap. It was originally thought that an entire soap factory had been found, complete with bars of soap, in the ruins of Pompeii. Pompeii was destroyed and frozen in time due to the volcanic eruption of Mt. Vesuvius in 79 AD. This has proven to be a misinterpretation, it is now thought that this building was used to clean and prepare textiles. Unfortunately this error has been repeated widely and can be found in otherwise reputable texts on soap history. While bathing is known to have been important in Roman life, cleansing with soap was not recognized as important until latter centuries of the Roman era. Soap was generally used as a treatment for skin diseases and cleaning textiles.

Soap made by the Gauls and Romans used goat's tallow (fat) and the ashes of the beech tree to produce both hard and soft soap. The name soap is derived from saipo, the term the Gauls used to describe the product of animal fats and plant ashes.

Muslim chemists in the medieval Islamic world were the first to produce soaps as we know them today. They were made from vegetable oils such as olive oil, aromatic oils like thyme oil, and lye. The formula for soap used since then hasn't changed. It is known that from the beginning of the 7th century soap was produced in Nablus (West Bank, Palestine), Kufa (Iraq) and Basra (Iraq) (4). Arabian Soap was perfumed and colored and some of the soaps were liquid and others were hard. They also developed soap specifically shaving. The Persian chemist Al-Razi was the first to record soap recipes in a manuscript. More recently a manuscript from the 13th century was discovered that details even more recipes for soap making (5).

In the Middle Ages, artisans worked independently to develop dyeing and soapmaking. Since creating good recipes required so much trial and error, the recipes became secret and were handed down from master to apprentice, and from father to son. Soap was largely developed for use in the cloth industry, to prepare wool for dyeing, and not for personal hygiene. Soapmakers in Naples were members of a guild in the late sixth century (6), and in the eighth century, soap-making was well known in Italy and Spain where soap was made with goat fat and Beech tree ashes. During the same period, the French started using olive oil to produce soap. Eventually, fragrances were introduced and soaps for bathing, shaving, shampooing and laundry began to be made. By 1200 AD, Marseilles, France, London, England, and Savona, Italy had become soapmaking centers.

From the 16th century finer soaps were produced in Europe using vegetable oils (such as olive oil) as opposed to animal fats. This switch to vegetable oil was not simply due to the fact that animal fat soap smelled so bad but also because its manufacture would deplete the nation’s tallow reserves, thereby driving up the cost of candles beyond the reach of the poor.

The most important step in the advancement of soapmaking came from two French chemists. Due to the inconsistencies in the concentration of the alkali extracted from ash, it was difficult to maintain quality control of the soap.  Sometimes it would be too oily and other times it would be too caustic. 

Nicholas Leblanc and Michael Chevreul around the turn of the 19th century help to overcome this problem. In 1791, Leblanc patented a method of making sodium carbonate or soda ash from commonly available salt. In 1811, Chevreul discovered the relationship and chemical nature of fatty acids, glycerin, and fats.

The standardization of sodium hydroxide (lye) production has allowed us to refine our recipes and be able to consistently make batches of soap that have the same qualities. We now know the saponification values for different oils, so we can calculate just how much lye is needed to completely saponify (turn into soap) a specified amount of oil. This ensures that we never have a batch of soap that has excess lye in it and we can control how much free oil remains in the soap to create a nice moisturizing bar.

Ladybug Soapworks Gingerbread Soap

References:

(1) Plants for a Future. http://www.pfaf.org/user/cmspage.aspx?pageid=49

(2) Willcox, Michael (2000). "Soap". In Hilda Butler. Poucher's Perfumes, Cosmetics and Soaps (10th ed.). Dordrecht: Kluwer Academic Publishers. p. 453. ISBN 0-7514-0479-9. 

(3) Pliny the Elder, Natural History, XXVIII.191.

(4) http://www.history-science-technology.com/articles/articles%2072.htm

(5) Chemistry Google e-book by Wikimedia Foundation

(6) Understanding the Middle Ages: the transformation of ideas and attitudes in the Medieval world, Harald Kleinschmidt, illustrated, revised, reprint edition, Boydell & Brewer, 2000, ISBN 0-85115-770-X.