In the U.S. the most common olive oils are Italian and Spanish. Olive oil is made by first crushing washed olives into a paste. The paste is macerated and then centrifuged to separate the oil and water from the solids. The water is then removed, leaving olive oil.
The flavor and color of the olive oil depend on the region and type of olives used. Whether the olives are harvested early or when they're more mature can also make a difference in the flavor.
Extra Virgin Olive Oil
This is the highest grade of olive oil. It comes from virgin olive oil production (mechanical with no chemical treatment), is considered to have a superior taste, and contains no more than 0.8 percent free acidity.
Even though it is the highest grade, the quality, aroma, flavor, color, and price can vary greatly from one brand to another. It's best to use extra-virgin olive oil in salads as a light and tasty dressing.
Virgin Olive Oil
This olive oil is slightly lower in quality, containing about 1.5 percent free acidity. It has a nice flavor and works well for frying and sautéing.
Refined Olive Oil
Olive oils labeled "pure olive oil" or just "olive oil" are usually refined olive oils. Refined olive oil is the olive oil obtained from virgin olive oils by refining methods that do not lead to alterations in the initial glyceridic structure. Refined olive oil has a free acidity, expressed as oleic acid, of no more than 0.3 grams per 100 grams (0.3 percent) and its other characteristics correspond to those fixed for this category in the IOOC standards. This is often a bland oil that may be blended with stronger oils.
Extra Light Olive Oil
This olive oil is lighter in flavor and color, not lower in fat or calories. Because this olive oil lacks flavor, it is excellent for baking and for any use where a high-flavor oil would be intrusive.
Cold-Pressed Olive Oil
Cold-pressed means the olive oil was pressed without heat. This olive oil is richer in flavor. If the label reads "first cold pressed," it's because it is the first press. This is considered superior to other cold-pressed olive oils and will have a higher price tag.