ISO 672

Soaps — Determination of moisture and volatile matter content — Oven method

Soap, which is the basic material of daily cleaning, is used frequently. Soaps offered for consumer use pass many quality tests. One of the tests performed on soaps is “Soaps - Determination of moisture and volatile matter content - Firing method” within the scope of ISO 672 standard.

The general principle of the ISO 672 test method is as follows:

• A sample of approximately 10 g is weighed with an accuracy of 0.01 g,
• It is placed in an oven controlled at 103 °C,
• Cooled in a desiccator and weighed again,
• The procedure is repeated until the difference in mass between two successive weighings is less than 0.01 g.

There are many reasons for determining the moisture content in soaps:

• It is a parameter used primarily in the evaluation of shelf life.
• High moisture content in soap, During storage it will cause excess water to react with unsaponified oil to give free fatty acid and glycerol in a process called hydrolysis of soap. For this reason, it is tried to have information about the moisture content.