Olives come in two main colors: green and black. The color of an olive is actually determined by its degree of ripeness. Green olives are unripe and black olives are fully ripe. There are also colors in between, including red and purple, which are color changes the olives go through on their trip from unripe to ripe. The notable exception to this is that some canned “black” olives processed in this country are picked green and then soaked in an alkaline solution and oxidized via exposure to air to turn them black.
An olive is also categorized according to its processing method. Because all fresh olives are very sharp and bitter in flavor, they need to be processed to make them edible. The processing removes an acrid, bitter-tasting compound called oleuropin, present in olive skin. There are several different methods, each of which leaches out the oleuropin. The different processing techniques include:
- Oil-curing: soaking in oil for several months
- Water-curing: rinsing and re-soaking in water for many months
- Brine-curing: soaking in brine for one to six months
- Dry-curing: storing in salt for one or more months
There are many styles and flavors of olives, based on variety, where it grew, ripeness, and processing method. Like wines and cheeses, regional styles account for hundreds of different olives. Until recently, this country had just a handful of olives available, and they often were identified by nothing more sophisticated than “black” and “green.” But times have changed, and most markets now carry a wide array of olives. The following is a list of a few that are more readily available. In spite of the increased complexity of olive names, there are still quite a few olives that are identified by more generic terms like “Greek black.”
- Agrinion: These are huge, dull green, brine-cured Greek olives with a sour taste and very soft flesh that is easily torn from the pit.
- Alphonso: These large Chilean olives are cured unconventionally in wine or vinegar, giving them a dark purple color, tender flesh, and a slightly tart, bitter flavor. They are easy to pit.
- Arbequina: Becoming more available in the United States, these tiny green Spanish olives have a meaty, smoky flavor. They are hard to pit.
- Bella di Cerignola: These large, bright green, brine-cured olives come from the Adriatic coast of southern Italy. They are mild and sweet with dense flesh. They are hard to pit.
- California Sicilian-style: These large, dull green, brine-cured, sometimes cracked olives have a crisp bite. They are hard to pit.
- French oil-cured: Small, sleek, and wrinkled black, these olives have a strong, intense flavor. They are easy to pit.
- Gaeta: These are small, wrinkled, salt-cured black olives from Italy. They have a strong flavor and are often hard to pit.
- Greek black: These are large, dark brown to purple, brine-cured olives with soft pulp and a gentle flavor. They are easy to pit. “Greek black” is sometimes the generic label for Kalamata olives.
- Greek green: These are plump, juicy, pale green, brine-cured olives with an acrid edge. They are easy to pit.
- Kalamata (or Calamata):These dark purple, brine-cured olives from Greece have a strong aftertaste. They are often sold packed in vinegar and are a familiar supermarket olive. They are easy to pit.
- Ligurian: Similar to Niçoise olives, these small, black Italian olives are brine-cured. They are hard to pit.
- Manzanilla: These popular, small to medium, brine-cured Spanish green olives have crisp flesh and a smoky flavor. They are easy to pit, though they are often sold pitted and stuffed with pimientos or almonds.
- Moroccan oil-cured: These oil-cured, shriveled, black olives from Morocco have a slightly bitter, smoky flavor. They are easy to pit.
- Niçoise: Salt-cured, small, dark brownish-purple French olives, Niçoise have a tart, sharp flavor with faint buttery undertones. Their large pit is often hard to remove.
- Nyon: These black, slightly wrinkled olives from France are salt-cured. They are easy to pit.
- Picholine: Small, pointy, pale green, brine-cured olives from France, picholines have a sweet, slightly acidic flavor and a crunchy texture. In this country they are usually packed in citric acid. They are hard to pit.
- Sevillano (or Queen):This huge, green, bland, brine-cured variety is grown in California and Spain. They are hard to pit.
- Sicilian green: These large, pale, greenish-brown, brine-cured olives from Sicily have a dense flesh and sour taste. They are easy to pit.
Types of olive oil
Pressed from green or ripe olives, olive oil can vary widely in flavor and color depending on the variety of olives used and the region they come from. There are hundreds of different varieties of olive trees, and some olive oils are blends of several varieties.
In addition to the varietal differences, the style of an olive oil also depends greatly on the ripeness of the fruit. When olives ripen—in the fall and winter—the olives change from green to dark purple. Olives harvested early will produce a more robust, peppery oil with lots of green, vegetal notes such as artichoke and grass. These peppery and bitter flavors in an olive oil are attributed to polyphenols. Olives that are picked later on in the season tend to produce a milder oil with a less-robust character and more ripe fruit flavors.
The price of olive oil is determined by numerous factors including production cost and any given year’s crop and weather conditions. Genuine extra virgin olive oil is more expensive because of the higher costs at each stage of production, from grove to bottle. In addition, olives for the best olive oils are often harvested by hand, a cost that is passed on to the consumer.
Virgin olive oils: Virgin olive oils are extracted from olives solely by mechanical means, without chemicals.
- Extra-virgin olive oil: This is the highest grade of virgin olive oil. Industry standards stipulate that extra-virgin olive oil must meet numerous chemical parameters including a free fatty acid content ≤ 0.08%. To earn the extra-virgin grade, the oil must also meet a sensory (organoleptic) standard. In a test by a trained taste panel using official protocols, an extra-virgin olive oil will have no defects of aroma or flavor, and some positive flavor of green or ripe olives.
- Virgin olive oil: Confusingly designated as “virgin,” this grade of virgin olive oil has slight defects of aroma or flavor and meets a lower chemical standard including higher free fatty acid levels. Virgin olive oil is starting to appear in the American market as a healthy but less expensive cooking oil.
- Cold-pressed or first cold press olive oil: This is archaic terminology from the era of actual olive presses; today almost all olive oil is extracted using a centrifuge. The terms are also redundant: All genuine extra-virgin olive oil will be from the first extraction and no excessive heat is used. The terms still appear on labels because consumers sometimes seek it out, but they are virtually meaningless except under European Community law, where it does indicate the use of a traditional press.
Refined olive oils: If a virgin olive oil does not qualify for the virgin designation as defined by its acidity level and other factors, the oil is then refined to remove off odors and flavors. The result is a bland, almost colorless oil that is blended with a small amount of virgin olive oil to give it some olive character. The two refined olive oil blends found in the American market are:
- Pure olive oil (aka Olive Oil, Classic Olive Oil): This is a blend of usually < 10% virgin olive oil and refined olive oil. These olive oils tend to have little flavor and are best used for sautéing rather than for salads.
- Extra-light olive oil: This refined olive oil blend has a lower percentage of virgin olive oil, making it paler in color with very little olive flavor. The label does not mean that the olive oil is lower in fat; the calories and fat content for extra-light are the same as for any olive oil. Labels now read “Extra Light (in Flavor)” to avoid confusion about the calorie content.
The section on olive oil was reviewed by Alexandra Kicenik Devarenne—founder of the Extra Virgin Alliance, a non-profit trade association representing producers of genuine extra virgin olive oil from around the world—on September 20, 2017.