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.
Dining and Cooking