(Olea europaea var. europaea – Family Oleaceae)
The olive is related to such ornamentals as lilac, forsythia, and jasmine, and descended from the wild olive trees called “oleasters” (see Silverberry).
These wild trees have existed for millennia, including in Palestine, as far back as the Bronze Age. They are thought to have been cultivated in Palestine or Syria well before 3000 BCE.
From there, the trees spread to Anatolia, Greece, Crete, Italy, southern France, Spain, and into central Asia.
Archeologists have found not only the stones of the fruit, but also the remains of olive mills and presses. Oil storage jars have been found in large quantities and were known to have travelled long distances by sea.
Today, the olive is cultivated worldwide in all suitable climatic zones, but 97% of them are still found around the Mediterranean, where they are of major importance for the production of olive oil.
The olive tree is an evergreen with foliage of a distinctive silvery-green. Deep rooted, the tree is slow to mature, but lives a very long time, with some gnarled old trees reputed to be many hundreds of years old and still fruiting reliably.
It is, however, very susceptible to severe cold. Frosts of 1870 and 1956 are partially to blame for a steep decline in the olive industry of Provence, France.
The fruit is a drupe with fleshy pulp and a high fat content. The large, fleshy eating olives are not processed for their oil (addressed separately), unlike the small varieties.
Green, purple, and black olives are available on the market, but cannot be bought “fresh”. The fruits are harvested when unripe and bitter. The bitterness is caused by a glucoside which disappears after preservation in alkaline or salt solutions.
Black olives, on the other hand, are harvested ripe, but then fermented and oxidized to preserve their deep colour.
Andalusia, Spain, is the principal olive-oil producing region in the world. One variety is head and shoulders above the others. Picual accounts for half the olive production in Spain. It takes its name from the shape of the fruit as it has somewhat of a pointed tip (pico in Spanish).
The chemical composition of this olive is remarkably balanced. Other leading olive varieties grown for oil include: Hojiblanca, named for the whitish undersides of the leaves, Lechin de Sevilla, grown mainly in the province of Seville, Manzanilla, and Picudo, is another olive with a pointy tip and yields a delicately flavoured oil.
In Greece, the major oil variety is Koroneiko, but it also is known for Kalamata and the brine-cured Naphlion. France provides the Picholine, Niçoise, and the Lyons, which are commonly black, dry salt cured, and bitter. Italy has Gaeta olives, which are black and wrinkled but mild tasting, often enhanced by herbs. The US offers more such general types as Sicilian-style, Greek-style, or “black-ripe pitted”.
There are many ways to cure the olive, whether it is green or black, but only some methods are listed here:
- water cured: involves repeated soakings and rinsings over many months
- brine-cured: involves sitting in a solution for one to six months
- dry salt cured: involves layering olives with coarse salt and takes three to four weeks
- oil-cured: which may mean soaking in oil for some months or may refer to dry-cured olives, which are then rubbed with oil
- lye-cured: involves a strong alkaline solution of wood ash or caustic soda