BS ISO 685:2020

What is ISO 685 about ? 

ISO 685 discusses the analysis of soaps.  

ISO 685 specifies a method for the simultaneous determination of the alkali content and the total fatty matter content of soaps (including liquid soaps), excluding compounded products. 

Who is ISO 685 for ? 

ISO 685 on analysis of soaps is applicable on: 

• Manufacturing of soap 
• Companies dealing with soap production 
• Retailers and suppliers of soap 

Why should you use ISO 685 ? 

Total alkali is a sum of the alkali bases combined as soap with fatty and rosin acids, as well as those corresponding to free alkali metal hydroxide or carbonates and any silicates present will be titrated under the test conditions. 

The total fatty matter is a water-insoluble fatty material obtained by decomposing the soap with a mineral acid under the conditions specified. 

ISO 685 assists in determining the alkali content and the total fatty matter of soaps to make good quality soaps.  

As a buyer of ISO 685, you can acquire the good quality of total alkali and total fatty content with the information of sampling, testing the portion, the test conditions and the results and the methods of expression used. This all helps in manufacturing and analyzing the soap. 

By adopting ISO 685 you can enhance the quality of your soaps by maintaining the required level of alkali and total fatty matter in soaps. 

What’s changed since the last update ? 

BS ISO 685:2020 supersedes BS 1715‑2.1:1989, which is withdrawn. It includes: 

• The addition of Liquid soaps and “until there is an excess of about 5 ml” has been changed to “until there is an excess of about 10 ml” 

• “Repeat the shaking until the aqueous layer has become clear” has been changed to “Repeat the shaking until the water phase is separated from the organic phase  
• Addition of “If the soap colour interferes with the methyl orange endpoint, a pH meter can be used to indicate the endpoint during titration