The olive tree grew wild in the middle east and its fruits have been used since prehistoric times. Its history is so ancient that no one knows who first pressed the olive for its oil or who thought of softening and preserving the fruit in salt or soda.
Along with the vine, the olive tree was one of the first plants to be cultivated and the practice spread from central Persia and Mesopotamia to Egypt and Phoenicia and then to Greece. By dawn of history all the peoples of the eastern Mediterranean lived by the olive and the vine.
Because of its importance as a soothing ointment and as a source of both food and light, the olive gained a religious and divine significance. One of the earliest references to the olive occurs in an Egyptian papyrus from the twelfth century BC. It is a deed of gift from the pharaoh Rameses 111 to the god Ra. In it he offers the olive groves which were planted round the town of Heliopolis: “ from these trees the purest oil can be extracted to keep the lamps of your sanctuary burning”
Legend relates that a cedar, a cypress and an olive tree grew on Adam’s grave on the slopes of mount Tabor. The Bible abounds in references to the olive. In Genesis it was an olive branch that the dove brought back to the Ark. Proving to Noah that the waters were subsiding after the flood. Ever since, the olive branch has been regarded as a symbol of peace and goodwill.
Greek mythology describes how Zeus promised to give Attica to the god or goddess who offered the most useful invention. it was Athena, goddess of wisdom and peace, who won with her gift of the olive tree and its soothing, nourishing oil. Athena became the goddess of Athens and her olive tree was said to be planted on the rock of the Acropolis. The story is commemorated in a frieze on the side of the Parthenon.
In the course of their travels the Greeks introduced the olive to Italy, where it soon established itself. The peoples of north Africa also cultivated the olive and it gradually moved along the coast through Tunisia to Algeria and Morocco and then north into Spain and Portugal.
In De Re Rustica, the Roman writer Cato tells his readers that every farm should place the olive high on its list of crops. the Romans brought their very practical skills to bear on the olive grove and its products and invented the screw press to perfect the method of extraction. They went on to improve the storage and distribution of oil.
The Romans were also responsible for the further spread of olive groves, taking the trees into northern Italy until there was hardly a province which did not produce olives or olive oil. They also introduced the tree into Provence, but they still could not produce enough to fulfill their needs. Clay vessels of Spanish origin unearthed in Italy, stamped with the seals of the exporters, show that Apanish growers filled the gap, as they often do to this day.
THE OLIVE AND ITS FRUIT
If you have never seen an olive tree look for an evergreen tree with leaves that are dark green on the top and covered with much lighter silver scales on the underside. It was this silvery colouring, shimmering in the breeze, that attracted the attention of the artist Van Gogh. Fascinated by their colour, he painted pictures of olive trees.
The trees are slow to grow, taking four or five years to yield their first fruits and another ten to 15 to reach their full capacity. Once established, however, the olive tree can live for many years.
There are stories of trees which have stood for 1000s of years. Some trees are known to have been around for 100 years or more, but really old trees are more likely to be the result of new shoots rising up from root systems which have survived the ravages of age or bad weather.
The unripe olive fruit is pear-shaped and green in colour, changing to dark purple or black as it ripens. All olives, if left on the tree, will follow this pattern. Green table olives are picked an cured before they have ripened. Others are left on the trees and picked when they are fully ripe.
Olives which are to be pressed for oil may be picked at any stage in their development but the yields from unripe olives will be very low and the oil can be very bitter. Most olives are therefore left to ripen fully.
CULTIVATION AND HARVESTING
There are at least 50 different varieties of olive, each with its own distinct characteristics. Some olives, such as the Spanish Picual, are particularly suited to the production of oil, others like the French Lucque make better table olives. Some, like the Italian Frantoio, produce a hot peppery oil, while the Italian Taggiasca gives a much softer and sweeter oil.
Most olive-growing areas have their own particular varieties of olive, some of which are not planted outside, very often the oils are produced from a random mix of these varieties. However some of the more sophisticated growers deal with their olives in much the same say as they treat their vines. These people grow the different varieties in separate olive groves, they press and bottle them separately. Alternatively they may blend the different oils to produce a consistent flavour each year.
Everything that happens to the olive tree from pruning in spring through flowering, fruiting an harvesting will have a bearing on the quality of the fruit and thus on the product it will yield. In many areas the methods used are traditional to that region.
The harvest is an extremely critical time as far as ripeness is concerned. Most growers want to produce as much good-quality oil as possible and this means optimum ripeness, but if the olives are left on the trees for too long they will over ripen and oxidize as soon as they are picked producing unpleasant oil.
Freshly picked olives seem quite robust and hard but in fact they are very easily damaged so they must be handled with great care. In the wealthier groves they are harvested by hand. The pickers climb ladders and comb the olives from the trees with rakes. Nets are stretched just above the ground to catch the olives as they fall.
In hot climates olives will start to oxidize as soon as they are picked.
In cooler climates the problem is less acute. Growers may deliberately leave their olives to stand for a day or two outside the mill. The olives start to heat up a little and so produce more oil. If this is carefully done it does not affect the quality of the oil.
A good deal of the olive crop in each producing country goes to large cooperatives or industrial plants to be processed into olive oil of various grades and into table olives. Some of these establishments have built up a reputation for good-quality produce.
The rest of the olives are pressed or processed on farms or at small local cooperatives. The quantities may be such that the oil is simply used by the grower, his family and friends, and perhaps his neighbors.
Other farms and estates produce somewhat larger quantities of oil which they press and bottle on the premises and sell as ‘single-estate’ oils. In recent years these producers have been able to establish a reputation for very high quality, which allows them to charge top prices for their oils. As more people come to appreciate the virtues of first-class olive oil single-estate oils are finding a growing market and are increasing in number.
Because there is such a close affinity between vines and olive trees and between wine and oil, a good may of single-estate oils come from farms and estates which also produce wine. This is particularly noticeable in central Italy and increasing in California.
Olive oil is produced, by purely mechanical means, from the fresh flesh of the fruits. In many places the simple process of grinding or milling the olives and then pressing them has changed very little since Roman times – the equipment has simply become more sophisticated.
PROCESSING OLIVES FOR OLIVE OIL
The old presses only managed to extract about 40% of the oil. This was known as the ‘First Pressing’ and the oil was often labelled as such. Sometimes it was also labelled ‘cold-pressed’
The next step was to add hot water to the paste and to press it again to produce the ‘second pressing’ or ‘hot-pressed’ oil – terms which rarely appeared on the label. The modern hydraulic press Extracts more than 90 per cent of the oil and the remaining pomace is then sent to the refinery for further processing. Thus there is no second pressing or hot-pressed oil. Some producers still like to put the old phrases on the labels of their bottles, but they have no meaning today.
The fruit is first separated from leaves and twigs and then washed. Two or three millstones crush the fruit and its pits to a paste. The pits are important: the broken parts help to channel the oil when the paste is pressed. The milling process continues for about half an hour. During this time the cells of the fruit start to break down and release the oil.
The paste is then spread evenly over small round woven mats which are piled up in batches of 30 or 40 on the hydraulic press. The paste cannot be pressed in one great mass because it is very elastic and would resist the pressure. The masts are designed to allow the oil to trickle out and down the stack and collect at the bottom of the press.
The presses produce a reddish-brown liquid which is part oil and part natural olive vegetable water. The two are separated in a centrifuge. The oil is now immediately stored in underground tanks which will keep it fresh for quite a long time. In the past this process was carried out by slowly decanting the oil into troughs. The oil was then skimmed off as it rose to the surface. Some farms still like to use this method today, in which case the oil may be labelled Affiorato. The pomace left on the mats from the hydraulic presses and the olive water will usually be sent to a refinery, where the last ounce of oil will be extracted for industrial use. Sometimes it is fed to cattle or put on the land.