Acidity (as % oleic acid) is the most fundamental measurement of olive oil. It is the primary indicator of olive oil purity and freshness. The quality of olive oil is directly related to the degree of breakdown of the fatty acids in the oil. As the bound fatty acids break down, free fatty acids are formed, which increase the % acidity of the oil. Acidity, is a measure of the free fatty acid present in the oil, which is directly related to its purity.

Normally, testing acidity is a complicated process requiring the use of various chemicals in a laboratory environment. With the HI-3897 test kit, it is possible to easily and accurately test the quality of olive oil at various stages of processing and storage to monitor and maintain the highest quality.

The HI-3897 kit utilises a titration method where the endpoint is visually determined when the colour changes from yellow-green to pink.