The cultivated olive (Olea europaea, Oleaceae) is one the Mediterranean’s most valuable and important culinary crops. Spain, Italy and Greece, followed by (to a lesser extent) Tunisia, Syria and Turkey, account for most of the world’s olive cultivation, 90% of which is transformed into olive oil.
In Greek cuisine, there’s an entire category of dishes named lathera, which translates to “cooked in oil”; the Greek word for oil is lathi. Lathera grew out of a simple peasant-style of cooking that was based upon whatever was readily available from the land. An entire Greek meal might consist of nothing more than an assortment of seasonal vegetables cooked with liberal amounts of olive oil and herbs. This style of cooking is a hallmark of the Mediterranean Diet.
The Greek author/poet Homer called olive oil “liquid gold”, although, when freshly pressed, olive oil is often a brilliant, bright shade of green. This is due to the presence of naturally occurring carotenoid and chlorophyll pigments. And, if you’ve ever tried a young, pressed olive oil, you may have noticed a peppery note that tickles the back of your throat. This sensation is due to the presence of polyphenols such as oleocanthal, potent antioxidants in plants that have been linked to a number of health beneﬁts, including decreasing inﬂammation, regulating blood sugars and potentially reducing the risk of heart disease and cancer.
Olive oil is also an example of a heart-healthy fat source, consisting primarily of monounsaturated fatty acids. Replacing saturated fats (such as those in butter, lard, and coconut oil) with monounsaturated fats (such as those in olive oil) is linked with a signiﬁcantly lower risk of heart disease. Further, research presented at a recent American Heart Association meeting indicates that eating olive oil once per week may be linked with making blood less likely to clot in people who are obese.
Not surprisingly, all olive oils are not created equally. Nonetheless, there are things you can look for in selecting high-quality olive oil. Extra virgin olive oil (EVOO), in addition to being the best quality olive oil, contains the highest level of health-promoting polyphenols. It’s unreﬁned, free of chemicals and other “defects.” It comes from the ﬁrst pressing of olives, normally within 24 hours of harvesting, extracted by non-chemical, mechanical means without the use of excessive heat. EVOO has an acidity of less than 0.8%. These high quality oils should be savored for their unique attributes, drizzled over a ﬁnished dish, a salad, or for dipping a piece of crusty bread.
Virgin olive oils also come from the ﬁrst pressing, though have an acidity of less than 2%, which makes it lower in quality; high acidity indicates that the fruit has undergone more damage and oxidative stress. Virgin olive oils are less common to see in stores. “Pure,” or “classic” olive oil has often been processed using agents such as acids, alkalis and heat, which strip the oil of its polyphenols, to extract as much oil as possible from the pulp that remains after the ﬁrst pressing. Pure olive oils, or less expensive extra virgin olive oils, can be used for everyday cooking (no need to spend a lot of money on such olive oil, just ﬁnd one that tastes good to you).
Look for a harvest date on the bottle (if you can’t ﬁnd one, look for the “best before” date and subtract 18 months). The longer olive oil is stored, the lower the polyphenol level. Unlike wine, olive oil does not improve with age. Buy olive oil that comes in a dark bottle (light and heat are enemies of olive oil). If possible, choose an olive oil that comes from a single source or country of origin, although labeling can be deceiving. For example, a product labeled “product of” only designates where the oil was packed and shipped, not where the olives were harvested and pressed. To ﬁnd out where the oil comes from you’ll want to look for the estate name.
Finally, use your palate as a guide. Peppery/pungent, grassy, fruity, and/or bitter notes are a sign of a desirable, high-quality olive oil – one that is newly pressed with strong ﬂavors, low acidity and possessing a high degree of antioxidants. Good EVOO should smell fragrant and fruity and taste like the olives from which it was pressed.