National Geographic : 1951 Sep
Olives, Oil-bearing Fruit from Southern Europe IN CROWDED countries, or those where conditions are not suitable for extensive meat production, men turn to plants for the oil they must eat to live. In lands border ing the Mediterranean Sea, the olive tree supplies much of this need. From 20 to 60 percent of a ripe olive is oil. Men extract almost a million tons of oil a year from olives. In Spain, which leads the world in olive oil production, 6 percent of agricultural pro duction is in olives. In Greece the propor tion runs as high as 18 percent. Italy ranks olives second only to grapes in importance; in Portugal they are the leading tree crop and the Portuguese consume nine-tenths of all the oil they produce. A Good Omen to Men Ever Since Noah The olive is another of the fruits that may be traced to the beginning of recorded history, and beyond. The earliest Hebrew books men tion the olive under the name salt or zeit. The story of the dove from Noah's Ark re turning with an olive leaf, as told in the Book of Genesis, is familiar to all. The olive was a very important and valuable source of oil to the early Hebrews, and was also cultivated by the ancient Egyptians. Today the wild olive, Olea europaea, is found from western India westward through out southwest Asia and all about the Medi terranean borders. It is not certain that it is truly native throughout that range. In some districts, especially about the edges of the present range, the trees may be escapes from cultivation. Language research indi cates that the true center of the olive species was probably the area from Syria to Greece. Certain it is that the olive was known and cultivated for its oil from the beginning of agriculture in Syria, in Palestine, in Egypt, in Greece, and, a little later, in Rome. The ancients used the oil for food, for medicine, and for anointing their bodies. In Rome a favorite saying was that a long and pleasant life depended on two fluids, "wine within and oil without." Olive oil was also burned in lamps for lighting. The olive requires a long growing season to mature its fruit, and is not tolerant of low temperatures. The tree is injured when tem peratures down to 15° to 100 F. occur. Thus its range in Europe is limited to coun tries around the Mediterranean. The Spaniards apparently introduced the olive into America. While it did not thrive in the humid climate and acid soil of the West Indies and Florida, it prospered in the drier air of Mexico. It was introduced into California with the establishment of the first missions. Since then, other valuable varieties have been brought in from Europe. Only in California and, to a limited extent, in Arizona has commercial olive culture de veloped in the United States. The industry here is primarily based on olives for pickling. Oil is extracted from the fruit which fails to grow large enough for that purpose. The olive fruit is green in color when im mature, turning to black as it ripens. For green olive pickles, the fruit is picked imma ture; for black olive pickles, it is allowed to become mature on the tree, but not soft ripe. When harvested for oil, the fruit is allowed to ripen fully. The olive fruit fresh from the tree, both green and ripe, is intensely bitter. In the pickling process the fruit both for green and ripe pickles is first soaked in lye solution to destroy the bitter taste. After thorough washing to remove the lye, the ripe olives are soaked in strong salt solution. They can be held for a long period in brine, but should then be soaked in fresh water overnight to remove the excess salt. After salting, they are canned commercially under steam pressures which hold them at a temperature of at least 240° F. for 60 minutes. In the preparation of green olives there are variations in the process to bring about the development of special flavors. Methods used to extract oil from olives vary greatly from one country to another, and depend in part on what the oil is to be used for. In some cases fruit is first crushed beneath rollers, then squeezed in presses-which may be simply flat boards with stones on top, or, in modern plants, costly hydraulic machinery. Since the oil is contained in the pulp of the fruit, stones are sometimes removed before pressing. In all cases where the oil is to be eaten, speed is essential between harvesting and pressing; oil left in bruised olives soon grows rancid. We Import as Much as We Grow There are large areas in the southwestern States of this country where olives can be grown successfully. Because of the great amount of hand labor, particularly in har vesting fruit, the growing of olives for oil has not developed on a large scale here. Total production of olives in this country, al most entirely in California, averages about 50,000 tons of fruit per year, of which about half is used for pickling and half crushed for oil. American imports of olive oil amount to approximately 15,000 tons per year. In addi tion, about 10,000,000 gallons of green olive pickles are also brought in annually from south European countries, mainly Italy and Spain.