What’s the Difference Between Extra-Virgin Olive Oil and “Pure” Olive Oil?

Extra-virgin olive oil is oil that’s gently squeezed out of the olives after they are crushed, along with their pits, into a paste. The paste is layered between rounds of wicker (or, nowadays, plastic) and allowed to exude oil, the weight of the paste providing sufficient pressure to release the oil. When, on a recent trip to Tunisia, I saw olive oil being made in this way, the oil that was released without pressure was called first-pressed olive oil or première pression à cru. The paste was then put under a press, yielding a less golden oil, the second pressing. Both of these oils are still considered extra-virgin olive oils because the oil is never exposed to heat or Chemicals. To qualify as extra-virgin olive oil, the oil must contain no more than 1 percent of oleic acid, an acid that results from rancidity. To avoid rancidity, the olives must be pressed within days—ideally, within hours—of being harvested. Virgin olive oil is allowed to contain more oleic acid than extra-virgin olive oil. “Pure” olive oil is made from oil that has a higher-than-acceptable amount of oleic acid and hence must be “purified” by treating it with Chemicals. “Pure” olive oil, while far less expensive, never approaches the flavor of extra-virgin olive oil. It is, however, useful for frying and sautéing, processes whose high heat destroys the flavor of extra-virgin olive oil. I use “pure” olive oil where others might use vegetable oils, because, while its flavor is hard to detect, it’s at least innocuous.