Olives are the edible fruits of the olive tree (Olea europea). It is native to regions surrounding both the Mediterranean and Caspian seas, as well as parts of Africa and Asia. As the source of olive oil, the olive is an important agricultural resource and consequently cultivated in many other areas including California.
Varieties of Olives
There are five natural subspecies of olives and thousands of cultivated varieties. In Italy alone, there are at least 300 selective varieties with the most popular being Leccino, Frantoio and Carolea, which are commonly used in Italian olive oils.
The stage of ripeness will often determine the color of olives. Many varieties change from pale gold, to green, then purple, and finally to black when fully ripe, although some varieties remain green even when fully ripe.
Olives can be harvested at different stages depending on what they will be used for and the purple stage is considered to be the best for producing olive oil.
Why Are Olives Cured?
The raw flesh of an olive contains a bitter-tasting, naturally-occurring chemical called oleuropin and must be cured to before they can be eaten.
Supermarket-variety canned olives are often cured with lye (sodium hydroxide), but the varieties you'll find at self-serve olive bars or jarred in specialty stores are generally cured in either oil or brine or dry-cured in salt.
Popular Varieties of Cured Olives
- Kalamata: A black, Greek olive cured in a vinegar brine
- Nicoise: Tiny, tree-ripened olives from Nice, France
- Manzanilla: Brine-cured, green olives from Spain (often stuffed with pimentos)
- Cerignola: Extra-large, green olives from the Puglia region of Italy
- Picholine: Crisp green olives from France
How To Store Olives
Unopened, jarred olives can be stored in a cool, dark place for up to 1 year. Opened jars or refrigerated olives can be stored in the refrigerator for up to 2 weeks.