QA27 Test: Understanding Free Acidity in Extra Virgin Olive Oil
حُرِّر هذا المقال بمساعدة الذكاء الاصطناعي وراجعته هيئة التحرير.
What is free acidity in olive oil?
Free acidity is a key chemical indicator of olive oil quality. It measures the proportion of free fatty acids present in the oil, resulting from the degradation of triglycerides through enzymatic processes, heat, or improper handling of the olives.
High acidity generally reflects:
- a late harvest or damaged olives,
- an excessively long delay between picking and extraction,
- inadequate storage conditions.
The QA27 test: principle and method
The QA27 test refers to the standardised analytical method used to determine the free acidity of an olive oil, expressed as a percentage of oleic acid (% m/m). It is based on an acid-base titration:
- An oil sample is dissolved in a suitable solvent (ethanol/ether mixture).
- The solution is titrated with a potassium hydroxide (KOH) solution in the presence of a colour indicator.
- The result is calculated from the volume of KOH consumed.
This method is described in the reference standards of the International Olive Council (IOC) and incorporated into the European regulations applicable to olive oils.
Regulatory thresholds to comply with
To be classified as extra virgin, an olive oil must have a free acidity less than or equal to 0.8% oleic acid. Beyond this threshold, the oil is downgraded to a lower category:
- Virgin olive oil: acidity ≤ 2.0%
- Ordinary virgin olive oil: acidity ≤ 3.3%
- Lampante olive oil: acidity > 3.3% (not intended for direct consumption)
Why this test is central to export quality control
In the context of B2B trade and Tunisian exports, the QA27 test is systematically required by international buyers and certifiers. It appears in most specifications, alongside other analyses such as the peroxide index or spectrophotometric absorbances (K232, K270).
For Tunisian producers and exporters, mastering this parameter from the moment olives are received at the mill makes it possible to:
- secure the classification of the produced oil,
- enhance the value of superior quality batches,
- meet the requirements of European and international markets.
On EvooTunisia, all listed batches are accompanied by their analysis results, including the QA27 test, to guarantee transparency and confidence in every transaction.
