Onsa's Olive Oil

As a very flexible rule, extra virgin olive oil can be stored for about a year. It likely will not go rancid after a year, but the flavors will mellow as the oil matures. There’s often a best by date on the bottle that is usually 1-2 years after it has been bottled.

What’s the best way to store olive oil?

Keep it in a relatively cool, dark place. Heat and light are enemies, so keep it away from window sills and stove sides. There’s no need to refrigerate, in fact, we recommend you avoid it.

When can I expect the next season’s olive oils to arrive?

Most of our olive oils come from the Northern Hemisphere, so the olives are harvested in the fall. The pressing and bottling happens in the fall or early winter. For any oils that aren’t produced in the United States, we’ll then wait for them to slowly make their voyage across the ocean to us. Keep an eye out for new harvest oils to be on our shelves by late spring or early summer.

Light & Elegant

The most delicate oils. For an olive oil novice, this is where I recommend starting. These oils are often made near the seaside, which makes them a perfect match with baked fish.

Buttery & Silky

Lovely, rich, smooth oils – without any bite. If you want to taste the fruity parts of the olive without the peppery kick getting in the way, here’s the place to look. Good as a substitute for butter or when you want to play up the sweetness of an oil.

Smooth & Assertive

Intense oils, but not over the top. These have loads of flavor but not as much spicy kick as some others. In my opinion, these are the best all-around oils for pasta, dipping bread, and more.

Rustic & Fruity

The most intense oils. Loads of grassy flavor with a peppery, spicy kick. Use these alongside bold foods, like drizzled over grilled steaks or vegetables.

Why does one olive oil taste different than another? There’s a few key factors that impact flavor:

1. Olive varietal

Just like wine made with Chardonnay grapes tastes different than wine made from Merlot grapes, olive oils made from different types of olives can have totally different flavors. There are thousands of different olives in the world. Some are milder. Some are more bitter. Some are more buttery. Each will imparts its own flavor when pressed for its oil.

2. Harvesting and production

Olives ripen in the fall. They all start green. If you leave them on the tree long enough they will all turn black. If you want a pepperier, grassier tasting oil, it’s better to look for one that was harvested earlier in the season when the olives were greener. If you’re looking for a richer, more buttery oil, you’re better off looking for one harvested later in the season when the olives were blacker. Not all olives ripen at the same time, so an oil maker looks for a certain mix of ripeness on the trees – green, brown, purple, black – before picking.

Generally, the best oils are pressed just hours after picking, while poorer quality, less flavorful oils may take longer and be treated less carefully. There’s one significant exception, however. In southern France, a few producers still use a traditional method where the olives are intentionally left to sit for a few days to ferment before pressing, creating deep black olive flavor and rich, buttery textures.

3. Region

Around the Mediterranean, olives have been pressed to make oil for thousands of years. Different regions have developed their own particular takes on oil. Many regions have unique olives found nowhere else, like the bold Coratina that’s widespread only in Puglia. Different regions can also have different standards for how ripe the olives should be when harvested, or how to handle the olives after picking. Since these traditional varietals and methods are often quite localized, knowing where a Mediterranean olive oil comes from can often be a shorthand into predicting what it will taste like.

Annual weather patterns matter too. Having a hotter, drier summer can make for a more intensely flavored oil; rain during the autumn harvest may water the flavors down. The only way to truly know what each year’s harvest is like is to taste. At Zingerman’s, we do that step for you! Each year we taste all the new harvest oils and update our tasting notes for each oil.

“Extra virgin” is a legal term used to categorize olive oil. It’s like the USDA ratings for beef: Prime, Choice, and Select. For olive oil, the standards are set by the IOC, or International Olive Council, an organization set up by the UN to coordinate and promote olive and olive oil production.

Just like the USDA beef ratings, the IOC specifies a hierarchy for olive oils. From highest to lowest quality, the rankings are: extra virgin olive oil, virgin olive oil, and ordinary olive oil (on labels, it’s usually just called “Olive Oil,” or sometimes “Pure Olive Oil”). There are additional lower rankings of olive oils that aren’t for consumption, just like how beef that ranks lower than “Select” still gets used for other products, like dog food.

There’s a three part test for extra virginity: how it’s made, its chemical composition, and how it tastes.

First, extra virgin olive oil, virgin olive oil, and ordinary olive oil must all be made only from olives, and processed only by mechanical means (which is to say, no chemicals can be used). These might seem like no-brainers, but since ancient Roman and Greek times and continuing to today, conniving oil salesmen cut good olive oil with cheaper oils, like sunflower oil or heavily chemically refined olive oil, to boost their profit margins.

Secondly, extra virgin olive oil must have less than 0.8% oleic acid, which, counterintuitively, is the name for a type of fat, not an acid like vinegar. Oleic acid occurs naturally in olives and many other vegetable and animal fats. As olive oil oxidizes—which is a technical way of saying, as olive oil goes rancid—the amount of oleic acid increases. In other words, an extra virgin olive oil must be less than 0.8% rancid. Virgin olive oil must have between 0.8-2% oleic acid. Ordinary olive oil is between 2-3.3% oleic acid.

What makes for more oleic acid? One big factor is how the olives are handled. Like apples, olives will bruise if they get bumped around. And just like how an apple that falls to the floor is probably still pretty good if you eat it immediately but develops a big, mushy brown spot if you let it sit for a few days, a bruised olive gets worse the longer it sits around, too. To produce olive oils with low oleic acid (and also ones that taste great), it’s best to handle the olives gently and get them to the mill as quickly as possible. After pressing, the oil should be stored away from light and oxygen, both of which will oxidize it (and thus create more oleic acid) over time.

Third, extra virgin olive oil must meet certain flavor standards. First, it should taste “fruity,” which, as the IOC uses it, means that it should taste like olives. The IOC also considers bitterness and pepperiness to be positive flavor attributes for oils. Secondly, an extra virgin oil must not have any flavor defects. In particular, it should not taste muddy, winey, or rancid, each of which indicates poor handling of the olives. Virgin and ordinary olive oils are also supposed to taste fruity, but they’re allowed to have some flavor defects.

Does “extra virgin” mean the oil is good?

In a word, no. It does mean in most cases it should be better than oils labeled as virgin or just plain olive oil, but there’s an enormous range in quality of oils labeled as “extra virgin.” What’s more, thanks to the alleged widespread adulteration and corruption in the big olive oil industry, a vast proportion of what’s labeled as “extra virgin” doesn’t truly meet the IOC’s standards. For a deeper look into olive oil fraud, check out Tom Mueller’s fascinating book, Extra Virginity.

So how do you buy a good oil? Oils from smaller producers—especially those grown and pressed on a single estate (which is the case for practically every oil we sell)—are much less likely to be tampered with. But the best advice I can give you is to taste it. If an oil tastes good to you, and gives good flavors to the foods you eat with it, then it’s good.