To make virgin olive oil, machines extract oil from the olives without adding anything more than water during the process. More specifically, as American olive oil expert Alexandra Kicenik Devarenne writes in Olive Oil: A Field Guide, virgin olive oil “is natural olive oil, made solely from olive fruit, mechanically extracted under conditions (particularly temperatures) that do not lead to changes in the oil and that has not undergone treatment other than washing, separation (decantation and/or centrifugation) and filtration.”
Part of what defines an olive oil’s type is its free acidity. For olive oil, we discuss “free acidity” or “free fatty acids” (FFA), not simply “acidity,” as Devarenne told me, because we are not referring to the sort of acidity we find in a lemon or vinegar. When free acidity goes up, good flavor and quality go down, because the olives were fermenting, rotting, or damaged before their oil was extracted. But that’s not all there is to it; in addition to many other chemical factors, an olive oil’s flavor is crucial to its designation. All standards designate extra virgin olive oil as the highest grade, with its very low free acidity (no more than 0.8%), some fruitiness, and a lack of flavor defects.
Virgin olive oil that doesn’t make the cut for extra virgin may have some mild flavor defects and a higher free acidity (up to 2%), while the IOC’s category of “ordinary virgin” can have up to 3.3% free acidity. What the IOC considers “virgin olive oil not fit for consumption as it is” and designates “lampante virgin olive oil” has a higher free acidity and/or other flavor defects. Lampante virgin olive oil requires refining before it can be eaten.
What is often called “olive oil” and “light olive oil” or “light tasting olive oil” in the US is a blend of extra virgin or virgin olive oil with a much larger percentage of refined olive oil. Devarenne explains that refining uses high temperatures and a great deal of manipulation to produce an odorless, colorless, flavorless, mostly monounsaturated fat from a virgin olive oil with serious flavor defects and high free acidity. During refining, volatile compounds and the very healthy polyphenols in virgin olive oils are lost.
So, Devarenne concludes, “when choosing olive oil for its health benefits, using virgin olive oil instead of refined makes sense because of the so-called ‘minor’ components.” The virgin products have the polyphenols, tocepherols, etc., that research is indicating are “a big part of what olive oil does for you” health-wise. Are you looking for “really good flavor and the highest level of health” benefits? Use extra virgin olive oil—it’s the best. Prefer a cost conscious approach? Choose a virgin grade for cooking, and extra virgin for raw uses.
WRITTEN BY LISA RADINOVSKY