Production methods - European Olive Oil

Production Methods

The quality of what we eat is the result of the goodness of the raw material and the skill with which it is treated. The European olive oil is the perfect synthesis of these two factors. In this process, from harvesting to processing, the production method is one of the fundamental steps.

Each oil has its own uniqueness, which derives from the use of different cultivars and quantities of product.

However, the oil production process, which is divided into several stages, remains the essential element of the certified quality of the European olive oil.

Fruits Harvesting

The olive harvest generally begins in October and ends in February. Depending on the date of harvest and the ripeness of the fruits, the properties of the olive oils vary.

After the olives have been harvested in the olive groves, they must be transported to the mill as soon as possible, to avoid fermentation.

Once harvested, the olives are washed under jets of water to remove all foreign substances and avoid negative consequences on the organoleptic characteristics of the olive oil.

The olives are then weighed and stored in perforated crates that allow the fruits to "breathe".

Before moving onto the actual ‘extraction’, the olives are subjected to a thorough cleaning: first they are poured into a hopper and from there into a defoliator that sucks up leaves and impurities.

At the mill

The mill is the place where the olives meant for oil production are brought, and where all production processes take place. Once washed, the olives are ready for processing which consists in 3 phases: pressing, kneading and extraction.

The pressing is the phase in which the olives are crushed until obtaining a coarse paste that contains peel (epicarp), the pulp (mesocarp) and pits (endocarp) and performs a draining function that facilitates the subsequent separation of the oil from the paste.

The most used pressing methods are currently two: the traditional one, which is characterized by a ‘discontinuous processing cycle’ and the modern one, characterized by a continuous cycle performed by mills (no downtime).

The traditional method, which is gradually disappearing, is based on the use of granite millstones that crush the olives with their weight; the modern method instead uses hammer crushers or rotating discs and has the advantage of quickly crushing a large number of olives, obtaining a more uniform paste and minimizing the damaging contact of the olive paste with oxygen.

Kneading

The kneading consists of a slow and continuous mixing of the olive paste inside a machine called a kneader. This is a crucial and delicate step as it allows to break the water-oil emulsions that formed in the pressing phase, and blend together the must oil droplets to form increasingly larger drops that will be easier to combine in the extraction phase.

The kneading phase is carried out today in watertight stainless steel tanks in order to control the amount of oxygen, and possibly other inert gases such as nitrogen to come into contact with the paste.

During the kneading phase, which lasts about 30 minutes, the temperature of the paste must never exceed 29 degrees centigrade to preserve the organoleptic characteristics and properties of the oil.

Extraction

Extraction is at the heart of the manufacturing process. In this phase, three components - pomace, vegetation water and oil must - are separated from the previously obtained paste.

The process can be discontinuous or continuous.

Extraction by pressure is a discontinuous method: the paste coming out of the muller is placed on circular filter panels, perforated in the center (fiscoli) which are overlapped, with steel discs in between to equalize the pressure and stacked on trolleys placed under the press. Increasing pressure for about 1 hour allows the oily must (oil and vegetation water) to separate from the solid part (pomace) that remains on the fiscoli.

Continuous methods, most widely used today, obtain the separation of the oil from the solid part by resorting to other physical principles than pressure. The most common extraction method is centrifugation and exploits the different specific weight of the individual components. The paste coming from the kneading machine is placed in a large centrifuge or decanter which through a high speed separates the pomace from the oily must, which in turn is divided into oil and vegetation water by a special centrifugal separator.

Storage of olive oil

Finally, the oil is adequately stored in large containers, usually made of metal. Before being marketed, European olive oil is analyzed to determine whether it belongs to the category of extra virgin olive oil, virgin olive oil or lampante olive oil.
European legislation defines the different categories of olive oils and their characteristics. Finally, these characteristics must be reported on the label, so that the consumer can read and understand them easily.
Member States of the European Union carry out checks on olive oil samples, precisely to ensure that these standards are respected and that the products sold to consumers meet their expectations.
Bottles must be stored away from light and hot temperatures until they are transported to retailers and sold to consumers.

These storage conditions are essential to avoid oxidation of the oil that degrades its quality.