The olive and the tree on which it grows have been revered since ancient times. Archaeological digs have unearthed evidence that olive trees existed on the island of Crete in 3500 B.C. The Semitic peoples were cultivating the tree's fruit by 3000 B.C. They particularly liked to use the oil of the olive to anoint the body during religious ceremonies, and to light their lamps. An ancient Hebrew law prohibiting the destruction of any olive tree is still obeyed.
By the time of the Roman Empire, olives were a mainstay of the agricultural economy. The Romans also used the oil to grease the axles of wagons and chariots. The Greeks traded it for wheat; the elaborately decorated clay pots that they used to transport the oil became part of the civilization's burgeoning art industry.
The olive tree is mentioned frequently in the Koran and in the Bible. Noah receives the message that land is near when a dove arrives at the ark with an olive branch in its mouth. Greek mythology associates the goddess Athena with the olive tree and credits Acropos, the founder of Athens, with teaching the Greeks to extract oil from the tree's fruit.
A member of the evergreen family, the olive tree features a gnarled trunk and leaves with a silvery underside. Its strong root system is perfect for penetrating sand, limestone, or heavy, poorly aerated soil. The trees thrive best in regions with rainy winters and hot, dry summers. Although it may take up to eight years before a tree produces its first harvest, a single tree can live for centuries.
Early oil producers pressed the olives by crushing them between huge cone-shaped stones as they turned slowly on a base of granite. Today, most factories employ hydraulic presses, exerting hundreds of tons of pressure, to separate the oil from the olive paste. Spain and Italy are the primary commercial producers of olives and olive oil. Greece is close behind them. However, California, Australia, and South Africa are emerging as leaders in the industry. Some wineries are planting olives to offset poor wine harvests. Ironically, olive trees were planted in California by missionaries in the 1800s, which by the turn of the century were producing an excellent grade of olive oil. However, the market demand was weak so the trees were uprooted and grape vines were planted in their place.
In the late twentieth century, emphasis on good nutrition and a fascination with the so-called Mediterranean diet has resulted in a resurgence in the olive oil trade. Olive oil is touted as a monounsaturate that is healthier for human consumption than corn and vegetable oils. The oil is also promoted as a dandruff reliever and, when mixed with beeswax, a homemade lip balm. In the late 1990s, the United States and Canada consumed olive oil at a yearly rate of 147,600 tons (150,000 metric tons). The demand often exceeds the supply, and during the 1990s prices rose significantly.
The primary ingredient of olive oil is the oil that is expressed from ripe olives. In the late spring, small flowers appear on the olive trees. Wind pollination results in the blossoming of the olives, which reach their peak oil content approximately six months later. Thus, the olives are harvested from November to March, after they have progressed in color from green to reddish violet to black. It is often necessary to harvest olives from the same trees several times in order to gather olives at the same stage of maturation.
Since ancient times, workers have knocked the fruit from the trees with long-handled poles. The process has not changed significantly over the centuries. Modern poles resemble rakes. Originally, nets were spread under the tree to catch the falling olives. Many producers are now using plastic covers to cushion the fall and to allow for cleaner, faster gathering.
One quart (0.95 L) of extra virgin olive oil, the highest level of quality, requires 2,000 olives. The only added ingredient in extra...