Though much has been written about olive oil quality, how to purchase good olive oil, and related topics, it’s helpful to summarize the basics and add a note about excellence in olive oil and cost considerations.
There are two principle grades of olive oil relevant to American consumers: “extra-virgin olive oil” and what is termed simply “olive oil.” According the International Olive Council:
Extra-Virgin Olive Oil are oils which are obtained from the fruit of the olive tree through purely mechanical or other physical means (with no application of heat or chemicals), and which has a free acidity, expressed as oleic acid, of not more than 0.8 grams per 100 grams.
Olive oil consists of refined olive oil with some amount of extra-virgin or virgin olive oil added back in for flavor.
In order for olive oils to be classified as extra-virgin, they need to be free of defects. Of the various things that could go wrong with olive oil when the olives are harvested from the trees, transported to the mills, and undergo pressing and processing, rancidity is most likely the defect that more consumers are familiar with, having had experience with rancid nuts and other instances of rancidity with oils and oils in food.
However, assuming the olive oil is shipped defect-free, how it is handled by wholesalers, retailers, restaurants and home cooks is still important. Remember that the great enemies of olive oil quality are heat (other than for final cooking), light, and oxygen. Hence the message to all of us: store and handle olive oil properly. Extra-virgin olive oils, if properly stored and handled, should retain their quality attributes—including their distinctive taste and flavor profiles—for up to two years. But even after two years, the basic health-promoting chemical structure of the oils can remain for some additional time—again, if properly stored—even if the aromatics have diminished. Finally on cost: every year, more and more olive oil producers around the world are committing themselves to producing the highest quality olive oils, benefiting from the same kind of technical expertise and technologies that have transformed the global wine industry. In the case of the very best oils—from producers aiming for true excellence and not merely good quality—one will see a higher cost just as one does with wines that similarly target excellence.
Amazingly, many of the same people who will not think twice about spending $15 to $25 on a bottle of wine that is consumed in a single evening will resist spending that much on a bottle of excellent olive oil that may last them several weeks. Clearly, a rethink is required on that front. But it also helps if consumers purchase more than one type of olive oil, at difference price points, to maximize their investment for varying uses.
For restaurants and chefs, the challenge is parallel but somewhat different: how to turn olive oil from a cost to a profit. No restaurant operator gives wine away for free, but most expect to not be able to charge for olive oil given out with bread at the start of a meal or used in the preparation of that meal. Some have experimented with charging for an olive oil service, which can make sense if the operator can reliably deliver a uniform, high-quality or excellent experience—and perhaps call out the provenance of the particular olive oil served and/or what makes it special. An alternative is to make sure the very best olive oils used in the restaurant truly shine in the eyes of the guest, have good visibility on the plate, and are additive to what customers value.