How Soap is Made

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  • soap production: milling
  • soap production: milling
  • soap production: extrusion
  • soap production: pressing
  • soap production: cutting
  • soap production: bars on conveyor belt
  • soap production: bars on conveyor belt
  • soap production: conveyor belt
  • soap production: stacking bars
  • soap production: quality control
  • soap production: production team
  • soap production: bars
  • soap production: production team
  • soap production: bars with box

TrueBody Soap being manufactured and packaged

Soap (as distinguished from detergents) is made by the reaction between a fat and a strong alkali such as lye (sodium hydroxide), potash (potassium hydroxide), or soda ash (sodium carbonate). Lye produces a hard bar of soap whereas potash is used for soft or liquid soaps. Historically, the alkali was leached from hardwood ashes. In fact, it’s believed that soap was “discovered” when a chemical reaction occurred between ashes and animal fat spilled by a fire pit, probably helped by a little rain.

The chemical reaction that yields soap is known as saponification. First, the lye is dissolved in water and then added to the fat which has been melted to the form of oil. The mixture of lye water and oil is stirred until “trace” occurs and the mixture becomes a soap batter. Over time and with continued agitation the soap batter will continue to thicken. It is then poured into molds and left to cure which can take several weeks to complete.

A by-product of the saponification process is glycerine. Many mass commercial soap manufacturers often extract the glycerine and sell it as a highly profitable by-product to be used in higher priced products like lotions and skin creams. Conversely, many natural soap-makers will leave the glycerine in the soap to retain natural moisturizing properties.

The cured soap is compacted into small pellets. These pellets are now ready for soap finishing, the process of converting raw soap pellets into bars. Soap pellets can be combined with fragrances and other materials and blended in a mixer. The mass is then discharged from the mixer into a refiner which, by means of an auger, forces the soap through a fine wire screen. From the refiner, the soap passes over a roller mill (French milling or hard milling). It is then extruded into a long log or blank, cut to convenient lengths, passed through a metal detector and stamped into shape in refrigerated tools.

"Soap." Wikipedia, The Free Encyclopedia. 27 Sep 2008, 20:57 UTC. Wikimedia Foundation, Inc. 03 Oct 2008