So, you are standing in the supermarket aisle eyeing the olive oils, you see pure olive oil, extra virgin olive oil, light olive oil, and now you are thoroughly confused. What is what? What do these terms mean and what differentiates the grades?

First of all, let's look at the process of extracting oil from olives. The first step is that olives are picked, depending on the type of olive and the time of year it is picked will have a lot to do with how the oil tastes and how much oil will be able to be extracted. The variety of olives, plus climate, and process make the final oil almost as unique and varied as fine wine.

The picked olives are washed, and then sent to a mill and either pulverized or ground up, then the resulting mulch is sightly warmed and mixed to tease out the oil from the meat. The mulch is then laid out on mats that are stacked and then sent to a hydraulic press that slowly presses this mulch over a prescribed period of time to about 2200 lbs. per square inch! The run off from this pressing is vegetable water and oil. The oil is usually centrifuged or decanted from the water and the water is used as fertilizer or discarded.

This is what is referred to as a first cold pressing and the resulting oil, that has to contain less than a certain percentage of free oleic acid, is termed extra virgin. It has all the nuances and characteristics of the olive it is taken from. It is full bodied and can be, astringent, peppery, buttery, green, piquant. ect... This is olive oil in its most pure and expensive form.

Now the mulch that has been pressed into a cake still has oil therein. These cakes are sent to a refinery where heat and chemicals extract the rest of the oil out and refine it. Now you have a flavorless, colorless, vegetable oil that then has a little virgin oil added to it for flavor. Now you have pure olive oil, not a lot of flavor or body but the product is wholesome. Light olive oil does not contain less fat, it is just lighter in color and pretty much neutral in flavor, it is simply a highly refined olive oil.

Another reason olive oil may be refined is that the olives have been abused in some way, either they waited too long to go to press and started to mold or ferment, the mats started to mold and gave the oil a very off flavor, or the pressed oil may have started to go rancid. The various negative qualities that an oil can have, that is sign of abuse of the olives and/or oil, are fusty, musty, rancidity, burnt, muddy sediment, and winey, plus others. In any of these cases, any significantly perceptible qualities of this sort would make the oil unpleasant and unacceptable and so off the oil goes to the refinery to have all the positive and negative qualities refined out, what's left? Flavorless, colorless, vegetable oil that is spiked with a little virgin oil for flavor and there again you have pure olive oil, not a whole lot of flavor but wholesome and good for cooking.