From Olives to Olive Oil
The most important operation in olives growing, because of the
repercussions it has on the quantity and quality of the oil, is the harvest.
Harvesting the olives for the new season’s oil is a delicate operation. To ensure quality,
both timing and methods are of fundamental importance. Olives usually mature in late fall.
The best time to harvest them is as they are just turning from green to black when they
contain the most oil of the best quality.
However, the olives don’t all mature at the same time, even on the same tree. Therefore,
in order to render the harvest operation economically advantageous farmers need to
chose the time when the largest possible number of olives are mature. Only fresh olives
still attached to the tree can be made into high quality oil, so they must be detached from
the plant not picked up from the ground.
Several are the harvesting techniques and they depend on the type of the tree and the lie
of the land. The simplest technique is the "brucatura". It involves the picking of ripe olives
only and must be repeated several times during the fall and winter. The "pettinatura"
method involves the use of a special hand-held rake. This is limited to small olive tree
where the top branches are still within arm’s reach. Taller trees are harvested using the
"bacchiatura" method which involves beating the branches with poles and catching the
olives on sheets of canvas spread on the ground under the tree.
Opinions vary about whether hand picked olives are of higher quality than those
harvested mechanically. The high cost of manual harvesting (about 50 percent of the
production cost) has brought to the switching to mechanical harvesting when possible.
Newly harvested olives are washed, deleafed and crushed preferably by huge granite
stones, into paste made up of the olive pulp and pits. The paste in then spread on hemp
or nylon mats that fit on the steel disks stacked one atop of the other. Then the disks are
wheeled over on a cart to a hydraulic press where extreme pressure is exerted upon
them to squeeze out the liquid, which drips from the edges of the disks.
The mats allow the oil to drain and at the same time filter out the solid olive matter. The
liquid is collected and pumped into a separator, which whisks off the water by centrifugal
force and leaves a steady trickle of oil pouring out of its spout.
The product obtained from this process is classified as Virgin olive oil. It means that is
obtained solely by mechanical means under conditions, particularly thermal conditions,
that do not lead to deterioration of the oil. It has not undergone any treatment, other
than washing, crushing, preparation of the paste, separation of the solid and liquid
phases, settling and/or centrifugation, and filtration. Virgin olive oil is therefore the oily
juice of a fruit: the olive. It is virtually the only oil that can be consumed as it is obtained
from the fruit, and when properly processed maintains unchanged the flavor, aroma, and
vitamins that the oil had when in the olive.