First and foremost, let’s clarify what the terms first pressing and cold pressing mean?
First pressing means simply that the oil was obtained from olives that were crushed only one time. This term is mainly reminiscent of the way olive oil was produced years and years ago, when screw or hydraulic presses were used and the paste was subjected to increasingly high pressures with subsequent degradation in the flavor of the oil. Nowadays continous centrifugal presses are doing the job and therefore there is no second pressing. “Cold Pressing” is also more of a term from the past. A century ago, after the first cold press, hot water or steam was applied to the remaining paste to obtain more oil, degrading the quality and removing some of the healthy nutrients. Today, the olive paste is almost always warmed, but only to room temperature which does not affect the quality of the oil at all and is still considered “cold pressed”. Cold pressed today means that the olive paste was not heated over a temperature of 27ºC (80.6ºF). As mentioned before, this is important because exposing the olive paste to higher temperatures during pressing will yield a much bigger amount of oil but it will negatively effect the quality and amount of nutrients contained in the resulting oil.
Now let’s get to the types of olive oils…
After the first pressing, the olive oil obtained is classified by specialist tasters taking into account the following four attributes: Aroma, Flavor, Texture and Limpidity. The taster will attribute a score to each oil submitted for analysis and in accordance with the International Olive Council they are classified as follows:
Virgin olive oils: are the oils obtained from the fruit of the olive tree solely by mechanical or other physical means under conditions, particularly thermal conditions, that do not lead to alterations in the oil, and which have not undergone any treatment other than washing, decantation, centrifugation and filtration.
Extra-Virgin Olive Oil: Less or no more than 0.8% acidity and produced by the first pressing of the olive fruit through the cold pressing process. The aroma and flavor of the olive oil must correspond to the aroma and flavor of the particular variety of olive and the score given by the taster must be between 6.5 and 10. The texture must comply with the standards, the oil must be absolutely limp and again scores must lie between 6.5 and 10. It is used on salads, added at the table to soups and stews and for dipping.
Virgin Olive Oil: has acidity of less than 2%, and is judged to have a good taste with all attributes scoring between 5.0 and 6.5.
Olive Oil: Also know as Pure Olive Oil, is the result of blending refined oil with virgin or extra virgin oils. The refined oil is the product of various types of filtering of the so called Lampante Virgin Olive Oils, which are oils whose scores for aroma, flavor, texture and limpidity do not reach 5 points or their acidity exceeds 2% and are therefore not fit for consumption before undergoing refining. The actual refining process will make the resulting oil lose its aroma, flavor, acidity and color while maintaining a significant part of its vitamins. When, as a last step, an indeterminate amount of virgin or extra virgin olive oil is added, some of the original components are reconstituted, thus gaining some color, flavor and aroma back. Pure olive oil tends to be much lighter in color and contains much softer taste than virgin olive oil. This oil is a general-purpose (all-purpose) olive oil and refers to the fact that no non-olive oils are mixed in.
Pomace Oil: Obtained by submitting the solid mass or paste that remains after the crushing and pressing of the olives to a chemical process where steam and solvents are used to extract any residual oil. Pomace oil has a more neutral flavor than pure or virgin olive oil; however, it has the same fat composition as regular olive oil, rendering it the same health benefits. It also has a high smoke point, and thus is widely used in restaurants as well as home cooking in some countries.
Light & Extra Light" Olive Oil: We personally do not use these oils and they are not commonly found in the countries of origin. So in other words, the terms have been created to target the “weight-conscious” American mind of today and it is not by any means a classification of olive oil grades. The olive oil that you see on the supermarket shelf advertised as "Extra Light" or “light” olive oil contains the exact same number of calories as regular olive oil and is a mixture of refined olive oils that are derived from the lowest quality olive oils available through chemical processing. Sometimes, the olive oil is even cut with other vegetable oils. It is completely unregulated by any certification organization and therefore has no real precedent to what its content should be.