Olive oil production


Steps to quality olive oil production

The production of high quality olive oil depends on the one hand on factors over which the olive grower has either limited or no control (weather, climate, soil, olive tree diseases) and on the other hand on factors that the olive grower can influence decisively (using modern technologies and following appropriate methods for the cultivation, harvesting and processing of olives.

The olive is a fruit
The olive grower who seeks the production of the finest quality olive oil should recognise and follow this principle: the olive is a fruit and should be treated as such. The sensitive nature of the ripe olive fruit must be protected from high temperatures and from damage and scratches (abrasions). With the harvesting of the olive fruit the fermentation process begins and with it the possible development of defective oil if all measures are not taken to protect it and if the appropriate methods for olive fruit processing are not followed. Consequently the treatment of the olive as fruit is a necessary and essential condition for producing high quality olive oil.

Early control of diseases and pest
The weather determines to a large extent the quality and the quantity of the olive crop. In the spring, during the blossom of the olive tree, a small amount of water is needed, but not very much. A year with higher rainfall always means a poor harvest and poor quality.
Also insect pests (such as the olive fly) can deteriorate the quality and quantity of the harvest and consequently the quality and quantity of olive oil. This can especially happen  in the spring (May), when olive fruit formation begins. Rainy weather favours the development of the olive fly, which damages the young olive fruits. In order to avoid this, an early control of olive tree diseases and pests is necessary. In particular, harmful insects (olive flies, etc) which directly affect the olive fruit should be controlled in time and appropriate steps should be taken in order to keep the olive fruit intact and prevent its decay.

Harvest olives in the first stage of maturity

The methods of harvesting of olives play the biggest role in the quality of olive oil.

Olives should be harvested in the first stage of maturity (neither unripe nor over-ripe, in November/December). The riper the fruit of the olive tree is, the more easily it can be damaged and become decayed, contributing to an increase in the acidity content of the olive oil. Unripe olive fruits reduce the fruitiness of the olive. In addition, surveys have shown that the phenols (a substance contained in olive fruit and olive oil), which are advantageous to human health and which protect the oil from oxidation and therefore increase the lifespan of olive oil, are abundant in the first stage of maturation (November / December), and significantly reduced with over-ripeness of olives (January / February).Windfall olives are usually over-ripe or bruised and should not be used for high quality olive oil.

Harvest olives by hand

An olive grower, seeking a high quality olive oil, harvests olive fruits carefully. He picks olives by hand and avoids harvesting methods (nets, beating) that lead to over-ripping,?????? injury, abrasion and consequently to the decay of olives. He also separates different qualities and varieties of olive fruits and processes them separately. It is obvious that different qualities of olive fruits will produce different qualities of olive oil.

Avoid prolonged storage of olive fruits

He also avoids prolonged storage of olive fruits and transports fruits with care (without compromising the integrity of the fruit) to the olive oil press. He ensures that the size of transport boxes or bags is moderate so that the temperature, pressure and damage of olive fruits remains limited so that the quality will not be affected.
Quick pressing of olive fruits
The quick processing procedure (pressing) of olive fruits at a low temperature is essential for the production of high quality olive oil. The high quality oil comes from olives that have been processed immediately after harvest (within 48 hours) and at temperatures of not more than 27°C. Fast processing of olive fruits is the most important procedure to prevent the creation of acidity, to preserve all substances and ingredients in the olive oil unaltered, to protect the flavour and taste and to minimize oxidation. High temperatures destroy the oil’s vitamins.

Keep everything clean

During the processing of olive fruits everything should be kept clean. The failure to maintain cleanliness leads to the reduction in quality of olive oil, since olive oil aroma and flavour can easily be altered. Odours from the fermentation of waste products may come into contact with the olive oil. The cleaning of the equipment helps eliminate rancid odours that can also affect the flavour and taste of olive oil. Cleaning is particularly important in the olive fruit washing machine, where the water of the washing machine must be kept clean at all times.

The finest quality olive oil
To sum up, the best quality oil is obtained by the olive farmer who picks his olives at the beginning of ripeness (neither over-ripe nor unripe) by hand and takes them immediately (within 48 hours of the harvest) with care (without compromising the integrity of the fruit) to the olive oil press and processes them at a moderate temperature (up to 27C°). A moderate temperature is necessary for the protection of the aromas and reduction of oxidation.
An olive farmer still achieves a good quality if he shakes olives from the tree into nets or he beats them with sticks from the tree, and takes them to the mill immediately.

Both harvesting methods are costly, require a lot of work, bring a lower yield of oil, but finally obtain the best quality, i.e. the acidity content, in a good olive year, is here usually far below the limit of 0.8%.

An average quality of olive oil
An average quality is obtained by the olive farmer when he has left his olives to fall into the nets and only collected them when a large part of the olives have already fallen. If the olive farmer quickly takes them to the mill for pressing, a medium quality can still be obtained

A third category of olive oil
The third category of olive oil is obtained the farmer who leaves olives for a long period of time on the ground (nets) or packed in bags, waiting for several days until the olives are brought to the olive mill. This kind of harvesting contributes to a significant increase in the quantity of oil but at the same time also increases acidity, since the number of olive fly maggots has sharply increased alongside the proportion of already decaying olives.
European Union: regulation of olive oil quality characteristics

As mentioned above, the quality of olive oil – as all other products – depends on many factors. Olive oils can be distinguished from each other depending on origin, time and method of harvest, processing, and variety of the olives. They vary in colour from light yellow to dark green, smell from delicate to intense and can taste strong or mild, sweet or slightly bitter, fruity or nutty. Some gourmets even note flavours of artichokes, tomatoes, bananas, apples or grass, etc.
In 1990 (and amended in 2001) the European Union adopted regulations introducing binding quality characteristics for olive oil, based, in particular, on the proportion of acidity.  Freshly pressed oil, made from sound, freshly picked olives, normally has a pretty low “acidity”, in the order of well under 0.5%. Factors which lead to a high acidity in an oil are: fruit fly infestation of fruit, delays between harvesting and extraction, especially if the fruit has been bruised or damaged during harvesting, fungal diseases in the fruit, prolonged contact between oil and vegetation ?????????water after extraction.

The peroxide content is also a criterion of olive oil quality. Peroxides are the primary products of oxidation of olive oil. The more rancid or oxidized the oil is, the more peroxides are present.

From 1.11.2003, the word “cold” can only be mentioned for oils which are pressed at a temperature of not more than 27 degrees Celsius.

Olive oil categories:

1       Extra virgin olive oil

Is the most natural juice produced from the first careful pressing of olive fruits and has the most perfect and delicate flavour and aroma. It has an intense fruity taste and an aroma of freshly cut olives. Extra virgin olive oil meets the highest standards of olive oil production and it can be defined as such if it fulfils a series of chemical parameters  and its content of free acidity does not exceed 0.8%.  The lower the content of free fatty acids, the better is quality of this category of olive oil.

2       Virgin olive oil

This olive oil is the natural juice of olives obtained directly by mechanical methods. It has a less delicate taste and smell and a higher acidity level that extra virgin olive oil. Its free acidity varies between 0.9% and 2%.

3       Olive oil

Purified olive oil, to which, in order to improve its taste, is added between 20% to 30% of virgin olive oil. Its content of free acidity is usually low but cannot exceed 1.5%.

4       Olive Oil – Protected Designation of Origin (P.D.O.)
This is extra virgin olive oil which is produced in a certain geographical area or part or parts of some regions, where the climate, soil and variety of olives have favoured the production of exceptional quality olive oil, from the past to present. P.D.O. olive oils have the verification of the relevant European Union Committee and are subject to strict national and European standard checks. Its production is made in numbered bottles.

5       PGI – Protected Geographical Indication

EU definition PGI is slightly less stringent than PDO, but still demands that the product is produced in the geographical region whose name it bears. The geographical link must occur in at least one stage of production, processing or preparation. It is sufficient for only one of the stages of production to have taken place in the defined area; for instance, the raw materials may come from another region. This allows for a more flexible link to the region and can focus on a specific quality, reputation or other characteristic attributable to that geographical origin.