There is a soap legend according to which there was a hill in Rome called Mount Sapo. They say there was a temple on the peak of that hill where people would sacrifice animals, and their remains such as ashes and resulting grease would drop into a river. The women who used to wash their clothes in that river soon discovered that their clothes were cleaner when they used to wash them in the lap of the Mount Sapo. This is a charming story, but probably a lie. Nobody has ever heard of a hill called Sapo.
Soap was probably discovered in the fire pits used by hunters, over which it had rained. The animal fats have drained to the ground, into the ashes and the rains have wet the ashes and formed a brute kind of lye. Cavemen probably knew the recipe of soap. In the diggings of the old Babylon, dating as far back as 2800 BC, soap was found. An ancient Egyptian medical papyrus describes the properties of vegetable oils mixed with alkaline salts.
The interesting fact is that soap for personal hygiene and bodily cleaning seems to have appeared much later. Generally, it had been used for washing wool and doing laundry long before someone thought of using soap for cleaning himself. The ashes, oil or animal grease have been used by people to anoint their bodies in order to look distinctive or unusual.
In order to turn oils into soap, the ashes must be turned into lye. This process must have been the most difficult to achieve earlier by our ancestors. The process of making lye on an industrial scale has been invented in the 19th century and had a huge impact on soap industry. Before that time, most of the soap was made with the help of potassium. Caustic potash is a potassium salt which is still being used in the making of liquid soaps. Adding table salt or sodium chloride to harden soap was used at least in the Roman epoch.
Many ancient people have discovered the utility of soap. Ancient Romans, Celts, Hebrews, Phoenicians and Egyptians have known how to turn several oils and greases into soap. After the fall of the Roman Empire, a great part of Europe seemed to forget how to make soap. Because of that, personal hygiene has gained in popularity only in the 17th century.
But what kind of oils or greases did people use throughout the centuries? This has varied around the world, depending on culture and mentality, and also in the vegetation of each country. Thus, in the Muslim world, soap was made of olive oil, palm tree oil, laurel oil and others. In Spain, the region of Castilla is known for easy to make pure olive oil soap. It has a soft consistence; it is white and does not make a lot of foam. In time, soap producers have noticed that coconut oil soap produces more foam whereas palm tree oil soap stabilizes the mixture and makes it harder. Castor oil hydrates the skin and can also produce plenty of foam. There are many other types of oils used for their healing properties.
They put a tax on soap as a luxury product in the 19th century, and this was done especially by the British. After the taxing was over, ordinary people began to afford soap too. Soap was first sold in America in 1608, when the first soap producer came from England.
In the beginning homemade soaps were soft and were kept in barrels and used whenever necessary. Salt was added to soap in order to harden it, so that it could be cut into pieces. Ordinary people could not afford to buy such salts and make their own soap, but they were used by soap producers in order to make huge blocks of soap. The blocks were cut into smaller pieces called nowadays "cakes of soap" and sold to the great public, but they gained their popularity only in late 19th century. The discovery of the industrial processes for making lye out of brine instead of ashes has revolutionized the soap industry and made the mass production possible.
Nowadays we can enjoy the various fragrances and consistencies of soap: liquid soap, the good old solid soap but enriched with all kinds of oils and scents, bath gels and shampoos, all to our disposal, aren't we lucky to enjoy all this variety? We should have a fresh appreciation for them and be grateful for what we benefit from today in terms of hygiene!