The process of obtaining the oil, to be understood as a transformation, comprises several phases, which begin with the harvesting of the olive and end with the final packaging of the product. The different steps involved in processing are:
Collecting the olives: shaking
During the months of December and January, the shaking – in all senses of the word! – reaches the olive groves in order to harvest the olives that a few months later will have been transformed into the oils that are long awaited and desired countrywide. Shaking has been and continues to be the traditional harvesting system, which consists in shaking the branches so that the olives fall. Once the olives have fallen from the tree, they have to be taken as soon as possible to the olive-oil mills.
Reception: the olives enter the olive-oil mills
The first step that has to be taken in the olive-oil mills is to classify the fruit received. This ordering is usually carried out in terms of the variety, the degree of ripeness and the state of health of the olives. When they have been classified, they are subjected to a process of cleaning, washing, weighing and storage until the time comes for them to be milled.
Milling and beating: this is where the oil is released
The milling makes it possible to break the structure of the olive, without removing the stone, in order to release the liquid part. However, the beating involves separating the paste from the other elements in order to gradually extract the oil. The result of these two processes is the olive paste that will become oil in the future.
Separation of the liquid part from the solid part
This is one of the vital phases in terms of the quality of the end product. Once the paste has been obtained, the liquid part must be separated from the solid part. This process is carried out by means of selective filtration (the oil that remains on the upper part of the paste is extracted) and pressure extraction (in hydraulic presses the paste is distributed on stacked pressing mats or filtering discs and they are subjected to the pressure generated by the presses; from this process we obtain the oil, the vegetable water and the olive pomace. The oil that is obtained from the first pressing is of the best quality).
Liquid phase separation
Despite the fact that the liquid material is gradually refined, it continues to contain a small amount of solids, which of course have to be eliminated. This fresh separation can be carried out by means of decanting, centrifuging or by means of a mixed system that combines both procedures.
Classification and storage
The oil is stored in the olive-oil mill before being packaged and reaches the market in perfect condition to be consumed. During this phase, it will undergo favourable changes as it loses part of the bitter aromas and at the same time gains in sweet, pleasant nuances and sensations.
Ready to consume. Not all materials are suitable for packaging oil. The most widely used materials are PET, glass, tin and coated cardboard. It is advisable to use opaque containers that do not let light through so that the excellence contained in them is not altered.