Quality
Note, that the description: ‘Extra Virgin Olive Oil’, concerns the uniformity with the minimum of the official standards and does not refer to quality.
Quality, do means that all benefits of Olive Oil are present. They depend under the condition that:
The temperature from cropping, crushing the olives, storing, up to the bottling is the right one.
The delicate flavor of Extra Virgin Olive Oil is related to the presence of a large number of natural chemical compounds. Over 100 such compounds have been identified which contribute to the distinctive organoleptic characteristics of Extra Virgin Olive Oil. These compounds form part about 1% of Olive Oil.
But, they are the major volatile compounds and decompose if the temperatures –especially during milling- exceeds 30ο C.
Therefore the ‘cold pressing’ is so important.
When the Olive Oil is not stored in polyethylene bottles and/or in clear bottles meaning that it is exposed to light. Because then, the peroxides are increased to unacceptable degree in a very short time while if stored in dark bottles it can last 10 times longer.
Last but the worst most and important, is when the olive oil is not a refined/hydrogenated olive oil. Because this procedure is applied by filtering, charcoal treatment, heating, chemical treatment by alkali, boiling, depolarization, deodorization etc, which are used to adjust the acidity of olive oil which originate from diseased olive oils and/or olives which are old, rancid and/or has/have other defects and after refining or hydrogenation resulting a perfectly looking, brilliant but industrialized product with no any of the benefits of Olive Oil.