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Natural Soap

Making soap commercially

Soap is made commercially in huge vats, using a process called the continuous method. As its name suggests, this involves adding raw ingredients continuously to one end of the vat, and removing soap continuously from the other.

Saponification takes place almost immediately in the vat, as a result of high pressure, high temperatures and the use of a catalyst. After saponification, the soap is often exposed to hydrogen to make it harder. The glycerine is removed and sold separately as a moisturiser.

The continuous process makes it possible to make good-quality soaps from lower-quality fats and oils. Commercial soap is almost always made from tallow (animal fat) and usually contains synthetic chemicals. These chemicals and the lack of glycerine mean that the soap often irritates people's skin or causes allergic reactions.



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Practical Action - Technology challenging povertyEuropean Commission - Department for International Development

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