What makes an olive oil "extra virgin" instead of "virgin"?
Olive oils are classified according to the standards of the International Olive Oil Council. The International Olive Council (IOC) is an organization established by the United Nations that has been recognized as the global body setting quality standards for the olive oil industry for more than 50 years.
According to the IOC, both virgin and extra virgin olive oil are extracted exclusively using mechanical methods (no heat or solvents are allowed). After the oil has been extracted, it is sorted.
If the olive oil is found to be fruity, free of defects and with a free acidity of less than or equal to 0.8, it is classified as extra virgin.
If the olive oil has minimal imperfections and a free acidity between 0.8 and 2.0 is found, it is classified as virgin.
Both virgin and extra virgin olive oil have naturally occurring antioxidants and polyphenols. However, levels of antioxidants and polyphenols do not necessarily depend on whether the oil is extra virgin or just virgin - a bland-tasting extra virgin is likely to contain fewer polyphenols than a strong-tasting virgin.
Note that in North America, virgin olive oil is not generally sold at retail.
About extra virgin olive oil
Extra virgin olive oil is an unrefined oil and is the highest quality olive oil you can buy. There are very specific standards that oil must meet to receive the “extra virgin” label. Because of the way extra virgin olive oil is made, it retains more of the real olive flavor and has a lower oleic acid content than other types of olive oil. It also contains more of the natural vitamins and minerals found in olives.
Extra virgin olive oil is considered an unrefined oil because it is not treated with chemicals or altered by temperature. What sets it apart is its low oleic acid content and lack of sensory defects. It contains no more than 1% oleic acid and is typically golden green in color with a distinct flavor and a slightly peppery finish.
Although you can cook with extra virgin olive oil, it has a lower smoke point than many other oils, meaning it burns at a lower temperature. Ditch the expensive high-end stuff for dipping bread, dressing, dips, and cold dishes, and use the less expensive stuff for cooking and baking.
About pure olive oil
You may also recognize oil labeled simply as olive oil or virgin olive oil - that's what we would call "regular" olive oil. This oil is typically a blend of virgin olive oil and refined olive oil (heat and/or chemicals are used in the extraction of oil and the removal of blemishes from the fruit).
Virgin olive oil is an oil of lower quality than virgin or extra virgin olive oil, with a lighter color, a more neutral flavor, and an oleic acid content of 3-4%. This type of olive oil is all-purpose cooking oil.
What about light olive oil?
This is the type of olive oil where the name can cause some confusion. “Light” does not refer to this olive oil is lower in calories. Rather, it's a marketing term used to describe the oil's lighter flavor.