Liguria boasts an antique and excellent tradition in oil production, concentrated for the most part in the west, but there are also present some notable olive groves in the east.
From the oriental Mediterranean the use of olive oil for cooking spread slowly towards the West. The cultivation of olives came to Rome from Greece, through southern Italy after 580 B.C., when also the vines arrived on the hills of high Lazio and Etruria. In the classical period it was known in all the regions of the Mediterranean coast. There did not exist any substantial difference between the production of olive oil in the Near Orient to that of the classical world.
The paintings on the terracotta vases demonstrate how the olive was first tested to control the state of maturation and the quality: this was done by squeezing some of the fruit through a funnel into a small bottle and then controlling the taste and odour of the extracted oil.
The extraction of the oil was better done straight after the harvest; nevertheless sometimes the olives were stored on the pavement of the oil mill. As a first operation, the pulp had to be separated from the nut; and as the skin of the olives was very tenacious, the separation was done by means of crushing the fruit, this was followed by pressing.
The crushing was done in a very simple way, rolling a cylindrical stone to and fro over the olives placed in a container. The roller mill, known by the Romans as mola olearia, consisted of two cylindrical stones fixed at the same horizontal axis that was hinged vertically between them. When the central pin was rolled, the rollers turned rapidly at a adjustable distance above a flat receptacle that contained the olives. The pulp was separated in this way without crushing the nuts.
A perfected model - according to the story handed down by Pliny - was invented at Atene and was called trapetum: between the millstones and the bowl passing at a fixed distance of a Roman inch (1.8c.m.). In the Greek region of Olinto (in an excavation of which reports date back to the V century B.C.) was found five millstones of whose form and sistemation cleared up many doubts that were present in the minds of the archeologists.
The ancients, however, also knew a system of pressing defined as «beam», of probably Aegean origins. On the island of this sea, in fact, the cultivation of olives dates back to the beginning of the Bronze Age, but the testimonies regarding the equipment used for the crushing belong to a more recent age.
The most antique remains known today are of an olive press and a bowl for squeezing the olives, which was found in Crete and refers to the Middle Minoan period (1800-1500 B.C.). A «beam» press for olives dating back to about 1500-1400 B.C. was also found in one of the Cicladi islands. The construction of the press of this type is clearly indicated on many painted vases, above all of those with black figures done by Athenian ceramists in the VI century B.C. The «beam» press applies the principle of a lever: a end is propped against a space on a wall, or between two pillars of stone; the other end is pulled down and often loaded with heavy stones.
The olives, arranged in sacks or on wooden tables, were squeezed under the central part of the beam.
The liquid extracted was left to rest in vats, until the water was drained away through narrow tubes arranged at the bottom of these. The separation of the oil from the watery liquid was essential, as this liquid contained a bitter substance that could ruin the good taste of the oil. Afterwards, it was possible to have a second and third pressing, every one of an inferior quality to that before, and after the pulp was soaked in hot water. Generally, in this way, there were produced three different qualities of oil: the first, to be used for cooking, the others to be used in cosmetics and toiletteries.
Probably oil had its original habitat in Syria and the first people who thought of transforming a wild plant into a domestic species where, without doubt, people who spoke a Semitic language.
From Syria the journey was relatively simple until the Aegean islands; equally easy was its transplant in Greece, where it found unexpected luck and application that made it, then, indispensable to the ancient people of the Mediterranean.
The Greeks themselves - with every probability - planted olive groves in those vast and fertile territories known as Magna Grecia, the coastal area of Apulia, of Calabria, Sicily and Campania.
Notwithstanding the great use of olive oil in classical antiquity, there is again those who maintain that the first Italian region where took root the cultivation of olives was in Liguria: here the plant must have been brought by the Crusaders after the year 1000, having known it in Palestine. But probably this episode refers only to those particular species of olives that grow favourably on the harsh coast of the Gulf of Genoa, blown by the wind, that of the west, and that of the east.
It is however, indisputable that the use of olive oil in Liguria was widely spread in Roman times.
It is about a definite oil - known inaccurately - as “light”, which is of a low acidity, with a delicate taste with a tendency to sweetness, and of a very limpid aspect.
In Ligurian cooking, oil is used sparingly, but it is the condiment for all recipes (as butter and lard were not produced and used in different ways) and was used cooked but above all uncooked (enough to think of pesto and the sauces of nuts, pine kernels etc.) maintaining its excellent nutritional qualities.