What is Extra Virgin Olive Oil?
Extra virgin (EV) olive oil is the oil extracted from fresh olives using a mechanical process without the use of excessive heat or any form of additives or solvents. Provided that the olives are free from disease and they are processed into oil without delay using a clean mill they should produce an olive oil that has an aroma and flavour that is free of taste defects and as such is of extra virgin grade. It should be noted that EV oils can be legitimately made without using a press. In fact most EV olive oils made in commercial relevant quantities are not made by pressing but instead by centrifugation of the paste made by crushing olives. What pressing and centrifugation have in common is that they are both mechanical processes and neither involves the use of any chemical agents. The heat bit is more of a technical issue. You can extract more oil out of olive paste if you heat it up. However, the quality of the oil will suffer as a result. The application of some heat is necessary in order to extract commercially viable amounts of oil with good aroma and flavour. 28-30 degrees Celsius is the ideal with 32 degrees Celsius being the upper end of the temperature range used by most producers interested in quality.