Types of Olives

What are Olives?

Though you might not guess it from their savory flavor, olives are technically fruits. Olives belong to a family of fruits called drupes, which are often referred to as "stone fruits" thanks to the hard, stone-like pits found at their centers. This means that olives are actually related to sweet fruits like peaches, apricots, and mangos!

The pits found inside of olives are seeds of the Olea europaea tree, which is native to the Mediterranean region. Olives are an important ingredient in traditional Mediterranean cuisines, though today they're grown and eaten all over the world. An estimated 90% of the olives grown worldwide are used to produce olive oil, while just 10% are destined to become table olives.

Olives are known for their richly savory, complex, often salty flavor. In addition to great taste, olives are also packed with health benefits! They're high in healthy monounsaturated fats, which help to fight inflammation and support heart health. Olives are also full of Vitamin E and other healthy antioxidants, making them a great way to get your daily nutrients.

What's the Difference Between a Green Olive and a Black Olive?

It might seem like green and black olives are different varieties of fruit, but actually, an olive's color is an indication of its ripeness. Young, unripe olives have a green to straw-yellow color but as they mature, they will turn from green to red, purple, or brown, before eventually becoming black when they are fully ripe. In short, the darker the olive, the more ripe it was when it was picked.

Young, green olives typically have dense, firm flesh, and their flavor can be somewhat bitter. Fully mature black olives have a softer texture and a smoother flavor with less bitterness. Black olives also have a higher oil content than their green counterparts.

How to Cure Olives

If you were to pick an olive off a tree and pop it into your mouth, you would be met with a very unpleasant surprise. Olives contain high amounts of the chemical oleuropein, a compound that gives raw olives an intensely bitter flavor. In order to make olives palatable, this compound needs to be fully or partially removed in a process called curing.

Curing breaks down the bonds between oleuropein and the sugars in olives. Most curing methods involve fermentation, a process that converts the olives' natural sugars into lactic acid. In addition to removing their bitterness, fermenting alters olives' flavor and texture, making them softer and adding complexity and saltiness to their flavor profiles. There are a number of ways to cure olives; the most common methods involve the use of brine, water, salt, or lye.

Brine curing method:

• Soaking olives in brine, a concentrated salt solution, gives the fruits a unique flavor and leaches away their bitter compounds.
• Brine-cured olives are typically sweet and complex because the salt intensifies the fruit's natural flavors.
• Brine curing is a time-intensive process, typically requiring between 3 and 6 months, depending on the concentration of the salt solution and the olive variety being cured.




Water curing method:

• This method mimics the traditional Mediterranean technique of allowing olives to soak in temperate sea water in order to remove their bitter oleuropein.
• Water-cured olives are typically sliced or "cracked" (pounded with a mallet or rolling pin to break the skin) in order to expose the flesh before being submerged in cool, fresh water.
• The water is changed daily for 7 to 10 days - or longer if a less bitter end result is desired - until the olives are palatable.
• The olives are then transferred to a "finish brine" made of water, salt, vinegar, and sometimes fresh herbs, where they are left to continue curing for at least a month and up to a year.




Dry salt curing method:

• This curing technique involves packing olives with salt in wooden boxes or wicker baskets in order to leach out their bitter compounds.
• The olives cure for 5 to 6 weeks, then the salt is removed.
• Salt-cured olives are typically soft and shriveled - somewhat similar in appearance to raisins - because the salt absorbs their moisture. Some prefer to bathe the olives in olive oil in order to restore some of their juiciness and flavor.
• This method removes less oleuropein than other curing processes, so the final olives will be somewhat bitter.




Lye curing method:

• Soaking olives in a lye solution is the fastest way to remove the compounds that cause bitterness. Lye-cured olives soak in an alkaline lye solution for 8 to 12 hours before being thoroughly rinsed to remove any trace of lye.
• This method, often referred to as a "Spanish cure," is favored by large commercial manufacturers because it's very time- and cost-effective.
• The harsh lye can remove some of the olives' color and flavor, resulting in mild, buttery-tasting olives. An optional fermentation step after lye curing can help to restore some flavor.




Air / sun curing method:

• In rare instances, olives are allowed to cure on the branch or cure in the sunshine after they have been picked.
• Since fully ripe olives are naturally lower in bitter compounds, this air curing method produces fruits that aren't bitter, though the olives tend to be rather shriveled.

Frequently Asked Questions about Olives

Are olives a fruit?

• Yes, olives are the fruit of the Olea europaea tree. They are a member of the stone fruit family, meaning that they are related to peaches and plums.

What are olives good for?

• Olives have a wide variety of culinary uses. They can be eaten whole with or without pits and are sometimes stuffed with specialty ingredients. Olives are delicious toppings for pizzas, salads, or pasta dishes. They can be pureed to create a tapenade and included in other flavorful dips. Olives are also commonly used as a garnish for martinis and other savory cocktails.

How do olives grow?

• Olive trees grow best in coastal areas with long, warm summers and mild, wet winters. It takes about 5 years for an olive tree to bear fruit. Olive fruits grow on the branches of the Olea europaea tree. Young fruits are green, but turn to red, purple, and brown, before finally turning black when they're ripe.

How long do olives last?

• Unopened jarred olives stored in brine typically have a shelf life of 3 years; unopened canned olives are typically shelf-stable for 4 years. Once opened, it's best to store olives under refrigeration and consume within 3 weeks of opening. If you have doubts about the freshness of your olives, consult the "best by" date on the packaging.