Tests of Quality
Tests ascertain whether an Oil is actually made from Olives
There are a number of chemical tests which are used to ascertain whether an oil is actually made from olives and if it is extra virgin or not. One of these tests measures the ‘acidity’ or levels of free fatty acids in the oil. It is a good indication of how well the extraction process has been carried out. Extra Virgin Olive Oil must have an acidity level of less than 0.8%. Ordinary Olive Oil and olive Pomace Oil must have acidity levels of less than 1.00%.
Another test, the ‘peroxide test’, is used to check levels of oxygen in the oil. This is important because, as Olive Oil comes into contact with the air it starts to oxidize and thus to deteriorate. This test measures the degree of oxidation that has taken place so far. Extra virgin oils must have a peroxide level of less than 20.
Further tests are carried out for adulteration and to double check oxidation levels. There is also an important organoleptic or Taste Panel test. Even if an oil has passed all the chemical tests it must also have a ‘perfect aroma and taste’. If it does not it cannot be bottled as extra virgin oil and must go to the refinery.
In recent years some producers have printed acidity levels on their labels but under new European legislation producers who wish to show the results of tests must show the results of all of them, not just one.