How to Choose a Good Extra Virgin Olive Oil

There are different grades of olive oil based on its aroma, flavor, and chemical makeup.

Extra virgin olive oil (EVOO), the highest grade, must pass special chemical tests. These oils should have optimum (meaning low) levels of acidity and ultraviolet-light absorption. (High levels suggest poor processing or deterioration, among other things.)

Extra virgin oils should taste great, too, but they can taste (and also smell) different from one another. Some can be fruity and nutty, others grassy and herbal or pleasantly bitter and pungent. Many are a combination of those flavors.

The compounds that give EVOO its bitterness and pungency, called polyphenols, also contribute to making the oil healthy. Those antioxidants fight cell damage that can cause heart disease and other illnesses. EVOOs are also rich in heart-healthy monounsaturated fats.

Turning olives into extra virgin oil requires careful processing from the start. Pick them when “the olives are still green but starting to darken,” says Selina Wang, PhD, an olive oil expert in the department of food science and technology at the University of California, Davis. They’re washed and crushed, and the paste is spun in a centrifuge to extract the oil. The process, sometimes called cold pressed, preserves the antioxidants. No heat or chemicals are permitted, so these oils are considered unrefined.

The next grade, virgin, is also made without heat or chemicals. It has some chemical or flavor flaws (though it can still taste good) and may not be as rich in antioxidants. It’s also not easy to find. Virgin oils are widely sold in Europe but rarely in the U.S.

Products labeled just “olive oil” are a blend of heat-refined and extra virgin or virgin oils. They’re milder than EVOO or virgin, and lower in antioxidants. “Light” olive oil is mostly refined oil and has an even milder flavor.

In the U.S., making sure that you’re actually getting an extra virgin olive oil is more complicated than elsewhere.

Olive oil-producing countries in Europe, the Middle East, and South America follow standards set by the International Olive Council. In the U.S., the Department of Agriculture sets standards based on the IOC’s, as does the North American Olive Oil Association, but they’re voluntary. And olive oils imported to the U.S. aren’t bound by the IOC’s rules.

One exception: California has mandatory quality standards for evaluating the taste and grade of olive oils that are stricter than the IOC’s. But these apply only to companies that use olives grown in the state and that make 5,000 gallons or more a year.

Some olive oils carry a seal from the North American Olive Oil Association. This organization tests olive oils made by companies that pay to use its seal for purity and quality, choosing bottles at random from grocery store shelves. “Our seal gives consumers confidence that an olive oil is the real deal, then lets them decide for themselves if an olive oil’s taste is something that they like and will complement their cooking,” says Joseph R. Profaci, executive director of the NAOOA.  But of the 11 oils in our tests with the group’s seal, we found products that ranged from some we thought tasted very good to some that tasted fermented or stale.

Another seal you may see is from the California Olive Oil Council. Companies that make oil from olives grown in California can have this organization test their products. The seal can be used only for those oils that meet the state’s strict standards for extra virgin olive oil. All four of the California olive oils in our tests, even those without the label, were among our top-ranked oils.

We chemically tested three samples of each oil at a lab and had two experts and a trained panel evaluate the flavor. Our comparative analysis used Department of Agriculture criteria as a model, but our tests were not assessments of whether an oil complied with any standard.

Our experts assessed the overall quality of the oil and described the flavor profile of each one using standard industry methods. A good oil should be fresh and fruity with some bitterness and pungency. It should not taste fermented (fusty) from poorly stored olives, or stale, which indicates oxidation. The tasting was blind, with each oil served in special blue glasses so that the color—which is not an indication of quality—didn’t influence the experts’ evaluation. We also sent samples to a larger trained olive oil tasting panel as a cross-check.

CR gave high marks to 11 oils, recommending seven. (A later test of olive oils sold at Trader Joe’s found two others to recommend.) Three are CR Smart Buys, with one—Specially Selected (Aldi) Sicilian Extra Virgin Olive Oil—costing just 50 cents an ounce. Results for eight others were less consistent, though “they’re still okay for sautéing or roasting,” Keating says. Seven had off-flavors that even cooking may not hide.

CR contacted the seven companies with the lowest-scoring oils in our tests for their response to our findings.

The maker of Paesanol Unfiltered Extra Virgin Olive Oil said lab tests were a better indicator of quality than taste. The manufacturer of Terra Delyssa Smooth Extra Virgin Olive Oil said that it disagreed with our findings and that two panels it used found no problems. And the maker of the Botticelli Extra Virgin Olive Oil said off-tastes could have come from the product sitting too long on a store shelf or simply be “the ripe taste typical” of a Spanish oil. Other companies didn’t comment.

As with many other foods, fresh is best for olive oil. One way to check the age of an oil is to look for a harvest date on the bottle. This is the date when the olives were picked and crushed, and it’s the best indicator of how fresh an olive oil is, according to Selina Wang, an olive oil expert. “You’ll always want to try to buy the most recent harvest,” she says. If you’re buying an olive oil in January, look for a date from the previous fall for oil produced in the Northern Hemisphere or the previous spring for one produced in the Southern Hemisphere.

If you don’t see a harvest date, check the “best by” date. “Best by” or “best before” dates are typically 18 or 24 months from bottling, Wang says, suggesting that the company expects the olive oil will maintain its extra virgin grade until that date if the bottle isn’t opened. But a good move is to choose one with a “best by” date that’s furthest from the date of purchase. “Once the bottle is open, it’s important to consume it within a couple of months if possible,” Wang says.

Light, heat, and oxygen can affect the flavor of olive oil and deplete its antioxidants. Consider buying an oil in amber, black, or green glass, or in cans because they’re best for keeping light out. And once an extra virgin olive oil is opened, it begins to oxidize, so buy only as much as you’ll use in a few months.

Once you get the olive oil home, proper storage is key. Don’t keep it on a counter or in a cabinet near the dishwasher or stove to protect it from light and heat. And always cap the bottle tightly. This keeps air and oxygen from getting inside the bottle.