excerpted from

ScottFree, Celiac.com's Guide to a Life Without Gluten

Cooking with Olive Oil

“Extra Virgin Olive Oil” has less than 1% acidity and is produced by the first pressing of the olive through cold pressing. Keep in mind that “pressing” today means that the oil is now spun in a centrifuge. This oil is an unrefined natural product that has undergone very little processing. It takes approximately ten pounds of olives to yield 1 quart of olive oil.

When the “Extra” is left off the label and it reads, “Virgin Olive Oil”, it is made from olives that are slightly riper than those used in the production of extra virgin oil so it is a grade lower in quality. The acidity level is
slightly elevated to 1 ½ percent.

“Pure Olive Oil” (or just regular olive oil) comes either from the second cold pressing or the chemical extraction of the olive mash left over after the first pressing. This grade is also called commercial grade oil. Pure olive oil is much lighter in color and blander in taste than virgin olive oil. It is all-purpose oil that
is fine for use in baked products. “Pure” refers to the fact that no non-olive oils are mixed in.

“Light” and “Extra Light Olive Oil” have the same number of calories as regular olive oil. “Light” merely refers to the color of the oil. It is a mixture of various olive oils from the lowest quality of olives available
through chemical processing.