The most popular soapmaking processes today is the cold process method, where fats such as olive oil react with lye.
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Lye
Reacting fat with sodium hydroxide will produce a hard soap.
Reacting fat with potassium hydroxide will produce a soap that is either soft or liquid. Historically, the alkali used was potassium hydroxide made from the deliberate burning of vegetation such as bracken, or from wood ashes.
Fat
Handicraft made Marseille soapSoap is derived from either oils or fats. Sodium tallowate, a common ingredient in many soaps, is in fact derived from rendered beef fat. Soap can also be made of vegetable oils, such as palm oil, and the product is typically softer. If soap is made from pure olive oil it may be called Castile soap or Marseille soap. Castile is also sometimes applied to soaps with a mix of oils, but a high percentage of olive oil.
An array of quality oils and butters are used in the process such as olive, coconut, palm cocoa butter, shea butter to list a few. Each oil chosen by the soap maker has unique characteristics that provide different qualities to handmade soaps including mildness, lathering and hardness. For example olive oil provides mildness in soap; coconut oil provides lots of lather while coconut and palm oils provides hardness.
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Early History
The earliest known evidence of soap use are Babylonian clay cylinders dating from 2800 BC containing a soap-like substance. A formula for soap consisting of water, alkali and cassia oil was written on a Babylonian clay tablet around 2200 BC.
The Ebers papyrus (Egypt, 1550 BC) indicates that ancient Egyptians bathed regularly and combined animal and vegetable oils with alkaline salts to create a soap-like substance. Egyptian documents mention that a soap-like substance was used in the preparation of wool for weaving.
Roman History
It is commonly reported that a soap factory with bars of scented soap was found in the ruins of Pompeii (79 AD). However, this has proved to be a misinterpretation of the survival of some soapy mineral substance, [citation needed] probably soapstone at the Fullonica where it was used for dressing recently cleansed textiles. Unfortunately this error has been repeated widely and can be found in otherwise reputable texts on soap history. The ancient Romans were generally ignorant of soap's detergent properties, and made use of the strigil to scrape dirt and sweat from the body. The word "soap" (Latin sapo) appears first in a European language in Pliny the Elder's Historia Naturalis, which discusses the manufacture of soap from tallow and ashes, but the only use he mentions for it is as a pomade for hair; he mentions rather disapprovingly that among the Gauls and Germans men are likelier to use it than women [1]
A story encountered in some places claims that soap takes its name from a supposed "Mount Sapo" where ancient Romans sacrificed animals. Rain would send a mix of animal tallow and wood ash down the mountain and into the clay soil on the banks of the Tiber. Eventually, women noticed that it was easier to clean clothes with this "soap". The location of Mount Sapo is unknown, as is the source of the "ancient Roman legend" to which this tale is typically credited.[1] In fact, the Latin word sapo simply means "soap"; it was borrowed from a Celtic or Germanic language, and is cognate with Latin sebum, "tallow", which appears in Pliny the Elder's account. Roman animal sacrifices usually burned only the bones and inedible entrails of the sacrificed animals; edible meat and fat from the sacrifices were taken by the humans rather than the gods. Animal sacrifices in the ancient world would not have included enough fat to make much soap. The legend about Mount Sapo is probably apocryphal.
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