Soap Fats and Oils
From Halbeeg, the open encyclopedia · Af-Soomaali
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Soap fats and oils are the fats and oils used when making soap. Soap results from a chemical reaction between fat (also called oil) and an alkali (a basic substance such as sodium hydroxide). This reaction is called saponification, which means that fats are converted into soap and glycerol.
The type of fat used affects the properties of the soap: hardness, lather quality, color, and how quickly it hardens. For this reason, factories and people making soap at home typically mix two or more fats together to achieve the right balance.
The saponification process
Fats are made up of triglycerides—a single glycerol molecule bonded to three fatty acids. When an alkali is added, this bond breaks: the fatty acids become soap, while glycerol is released. If sodium hydroxide is used, the result is hard soap; if potassium hydroxide is used, the result is soft or liquid soap.
Types of fat
Common fats include olive oil, coconut oil, palm oil, castor oil, and tallow. Animal fats such as tallow and lard are also used. Coconut oil produces soap with high lather and hardness; olive oil produces soft soap with good cleansing properties.
Industrial and hand methods
Large factories typically use a continuous process in which fat and alkali are mixed together, then glycerol is separated out for sale. The hand method, known as the cold process, relies on the heat of the reaction itself, and the soap takes weeks to cure.