Not all extra-virgin olive oils were created equal.
Some extra-virgin olive oils are of good quality while some others simply aren’t. Although, it is always advisable to prefer extra-virgin olive oils, which must conform to specific quality parameters established by the law. However, even extra-virgin olive oils are not necessarily of the best quality.
In particular, the type of process used for the production of olive oil may give rise to some differences between one oil and another. There are two systems for obtaining oil from olives: extraction and pressing. An extra-virgin olive oil is of good if it was obtained by pressing and not by extraction with solvents. By pressing olives instead of using solvents you get a product that is richer in polyphenols.
Also, it is preferable that the oil you decide to buy was “cold-pressed“, which means that the temperature during the pressing should be about 27°C. Pressing at higher temperatures increases the yield but also diminishes the nutrient content of the oil.
Colour and taste are important parameters to keep into consideration when choosing which oil you want to buy. A dark green colour indicates the presence of chlorophyll, which is a natural antioxidant. A bitter taste indicates the presence of polyphenols, whose health properties are widely known. Moreover, a spicy taste indicates the presence of oleocanthal, which acts as a natural anti-inflammatory substance. If, on the other side, the oil tastes sweet, this indicates that the olives have probably been left to rest too long before being processed or that they have been harvested too late and they have lost a large part of their polyphenol content.
The choice of which olive oil to buy is not easy, I usually order it directly from a trusted producer. You can find the oil you like the most next time you’ll travel in south Europe and make an agreement with the producer to ship it to your country every year. It might cost you a bit more than buying it at the local supermarket, but you’ll gain a lot in terms of quality and taste!