Olive oil has never been a particular passion for me, although I cook with it almost daily. Its main appeal is utility—creating texture and moisture; browning without sticking—more than taste. But after attending a recent Smithsonian Resident Associates event about Italian foods, I won't be taking olive oil for granted anymore.
The speaker, Nancy Harmon Jenkins, is the author of The New Mediterranean Diet Cookbook, which promotes extra virgin olive oil as a healthful source of monounsaturated fat and antioxidants.
Jenkins is such a connoisseur that she compares extra virgin olive oils to wines, each with its own subtle complexities of flavor, color and structure, based on factors like terroir, production methods, and the type and age of the fruits harvested. There's one big difference, though, she noted: while wine improves with age, olive oil does not. It can lose its strongest flavors in a matter of weeks.
I was surprised to learn that unripe olives can make some of the most flavorful oils, and even more startled by photographs of such oils—such a bright, almost neon green! I've always assumed that olive oil should be golden, since that's what the main supermarket brands look like, but now I understand that the color reflects the maturity of the olives pressed. Darker oils usually come from riper olives and have milder flavors.
A few more surprising facts:
—The terms "first pressing" and "cold pressed" don't mean much on a bottle of olive oil that's already labeled "virgin." There is only one pressing involved, and it always takes place at ambient temperature, says Jenkins. Although some producers use heat and chemicals to extract any remaining oil from a batch of olives after a first pressing, this secondary oil cannot be labeled "virgin" and is usually sold for fuel or animal feed. The difference between "virgin" and "extra virgin" is the percentage of acidity allowed (up to 2 percent and 0.8 percent, respectively, according to the International Olive Council).
—Italians consume about 3 gallons of olive oil per person, per year, but Greeks consume the most in the world—about 5 gallons per capita annually!
—Olive oil goes rancid rapidly when exposed to light and heat, so although it looks nice in brightly-lit displays or sunny shop windows, you shouldn't buy those bottles (and you should scold your shopkeeper for damaging the oil, Jenkins says). At home, store most of your oil in the cellar and only keep a small container on the counter for daily use. Be sure to clean that container before refilling each time, so you won't end up adding good oil to rancid remainders.
For the tasting portion of the presentation, each of us received five plastic shot glasses filled with olive oils in various hues of greenish-gold. An authentic olive oil tasting, Jenkins noted, would have featured cups made of blue glass, so that our taste impressions would not be influenced by the oil's color.
She instructed us to hold each glass in the palm of one hand, covering it with the other hand, and make a swirling motion. (The point was to warm the oil slightly, but most of us simply spilled it on ourselves.) Then, following her lead, we lifted the glass to our lips and attempted to "aspirate" the oil, sipping and breathing in simultaneously to create a sort of mist on our palates. This resulted in a collective cacophony of slurping, choking, and chuckling among the tasting virgins, followed by a thoughtful silence while we tried to sort out the flavors Jenkins was describing. The Castello di Ama from Tuscany-Rivera was peppery; the La Spineta from Puglia was grassy (with an almond aftertaste, she said, though I didn't get that) while the Sicilian Olio Verde tasted like raw artichokes. The final one, a Monti Iblei from Sicily, tasted like green tomatoes.
Knowing all this, I admit that I'll still probably buy whatever extra-virgin olive oil is on sale at the supermarket most of the time (I can't afford to be a gourmet about everything), but I'll be adventurous when I come across an opportunity to sample different types. In the meantime, I'd better practice aspirating politely!
To get a visual sense of the production process from harvest to bottling, check out this Flickr user's photo essay of an olive harvest in Sicily, or this video about olive oil production in Tuscany.