Process of Manufacturing

processo-prod

The process of manufacturing olive oil begins in the fields, where the care taken during cultivation has to guarantee a sound final product at just the right point of maturity. The excellence of the oil is strictly tied to the quality of the oilves, to the care taken during the production process (picking, manuring, pruning, defence) and transformation (olive-pressing and all processes leading to the final product). Olive-ripening generally occurs at the end of autumn or at the onset of winter and its depends on the latitude at which plants are grown, or on the climatic state and the variety of the olive trees. In any case the picking takes place when the olives assume a partial or complete dark shade (the peel colour changes from green to purple). To delay picking does not mean a better oil yield, on the contrary a degradation process occurs that negatively effects the quality of the oil. There are numerous olive picking systems, however,  they can be grouped in 2 main categories: manual and mechanical picking.

Amongst the manual methods, the best results are achieved with the “brucatura” (browsing), with this method olives are hand picked individually and placed in special baskets hanging  from the harvester’s belt. This method is very slow and has a high labour cost. A faster variation of this method uses a special net which is laid on the ground under the olive tree and, as the olives are picked they are allowed to drop onto the net. However, the softer-pulp olive varieties are often damaged when they fall. Other manual methods are the “bacchiatura” (beating down) and the “raccattatura” (picking up).

Mechanical harvesting is basically the only option available for very extensive olive groves: mechanical arms are clasped to the tree trunk or the main branches of the tree with this method the drupe falls on to a net. Recently combs have been introduced. These combs are passed through the branches and the olives fall on a net laid on the ground. After picking, the olives are taken to the oil mill.

The transport phase is very important in order to obtain a good quality product. If the olives are transported in sacks or containers where the olives are subject to alterations, there is a possibility of triggering an undesirable fermentation processe, which could then inevitably effect the quality of the final product. The best way to transport olives is in crates or well-aired boxes; large companies use 200-300 kg pallettized boxes. In order to obtain a good quality oil, olives should not be dropped in heaps or stacked for a long time in the oil mill. It is advisable that they are pressed with-in 24 hours of the picking. Before the pressing, it is advisable that the olives are thoroughly washed in order to eliminate any possible foreign particles that could negatively effect the quality of the oil. The process of olive oil extraction can be divided into three main stages: frangitura (crushing), gramolatura (Kneading) and spremitura(pressing). The process of manufacturing olive oil begins in the fields, where the care taken during cultivation has to guarantee a sound final product at just the right point of maturity. The excellence of the oil is strictly tied to the quality of the oilves, to the care taken during the production process (picking, manuring, pruning, defence) and transformation (olive-pressing and all processes leading to the final product).

Olive-ripening generally occurs at the end of autumn or at the onset of winter and its depends on the latitude at which plants are grown, or on the climatic state and the variety of the olive trees. In any case the picking takes place when the olives assume a partial or complete dark shade (the peel colour changes from green to purple). To delay picking does not mean a better oil yield, on the contrary a degradation process occurs that negatively effects the quality of the oil. There are numerous olive picking systems, however,  they can be grouped in 2 main categories: manual and mechanical picking.

Amongst the manual methods, the best results are achieved with the “brucatura” (browsing), with this method olives are hand picked individually and placed in special baskets hanging  from the harvester’s belt. This method is very slow and has a high labour cost. A faster variation of this method uses a special net which is laid on the ground under the olive tree and, as the olives are picked they are allowed to drop onto the net. However, the softer-pulp olive varieties are often damaged when they fall. Other manual methods are the “bacchiatura” (beating down) and the “raccattatura” (picking up). Mechanical harvesting is basically the only option available for very extensive olive groves: mechanical arms are clasped to the tree trunk or the main branches of the tree with this method the drupe falls on to a net. Recently combs have been introduced. These combs are passed through the branches and the olives fall on a net laid on the ground. After picking, the olives are taken to the oil mill.

The transport phase is very important in order to obtain a good quality product. If the olives are transported in sacks or containers where the olives are subject to alterations, there is a possibility of triggering an undesirable fermentation processe, which could then inevitably effect the quality of the final product. The best way to transport olives is in crates or well-aired boxes; large companies use 200-300 kg pallettized boxes. In order to obtain a good quality oil, olives should not be dropped in heaps or stacked for a long time in the oil mill. It is advisable that they are pressed with-in 24 hours of the picking. Before the pressing, it is advisable that the olives are thoroughly washed in order to eliminate any possible foreign particles that could negatively effect the quality of the oil. The process of olive oil extraction can be divided into three main stages: frangitura (crushing), gramolatura (Kneading) and spremitura(pressing). Olive milling or frangitura Frangitura is a mechanical process that crushes the olives, this is necessary in order to crush the pulp from which the oil is going to be extracted. In order to do this one can choose between two technical solutions in frangitura: the traditional millstone olive press, and the hammer or disk mechanical press. The traditional method, called “a molazze”, that is by mullers, is composed of two large granite wheels that turn on a granite base, crushing the olives. The presence of olive stones does not harm the oil in any way, but rather, makes it easier to separate the oil from the solid component during the pressing process. The second solution is more time efficient than the first, but requires special care in order to avoid high temperatures.

The Gremolature


Before being pressed the olive pulp is subject to the process of gramolatura. The olive pulp and stones are re-mixed in order to reduce the volume and to separate the vegetable water from the oil, thus breaking up the oil and water emulsions created during the milling stage.

This operation takes place at a controlled temperature and  allows a delicate mixing of the olive pulp encouraging the oil to coalesce.

At this stage particular attention must be paid to both temperature as it should be low, and to processing times which should not be excessively long so that oil contact with air and light is as short as possible, whilst at the same time a good extraction yield is obtained.

Extraction


spremitura

Two methods can be used to extract the oil: the traditional vertical pressing method and the continuous centrifugation method.

In the latter case manpower saving is guaranteed but particular systems need to be adopted in order to prevent the oil from being subjected to high temperatures that could damage its quality. After further decanting and filtering operations the final product is obtained.

The basic difference between the traditional and the continuous system is that the speed of oil production  becomes a very important factor when you want to reduce the olive processing and storing times to a minimum.

We should, however, point out that the traditional methods require great professional experience in managing the plants and taking care of the state of the “fiscoli” (disk shaped mats on which the olive paste is spread after being crushed).

These, if not managed appropiately, are the main cause of oil defects. The continuous method gives excellent results, even though the crusher represents the crucial point as it gives more or less satisfactory results according to the raw material. In conclusion, undamaged olive pressing at controlled temperatures and sound olives guarantee the high quality of the oil.

We must mention that for the previous parametres described the EEC is revising them in order to achieve a better control on quality. In spite of the diffusion of oil cultivation, in the world panorama the use of olive oil is limited to the mediteranean countries.Where as the oils mainly used in the rest of the world are extracted from peanuts, soia, sunflower seeds  and cotton seeds.

We must, however, underline that the oil that is most adaptable in a kitchen used both for raw and cooked food is olive oil.

The classification of oil, is however, not simple. In various cases the names used can trick the consumer.

With the passing of time, oil changes and from the intense characteristic that it has in the beginning it becomes smooth and more harmonious; but after a year the oil begins to deteriorate.

Once separated from the vegetable water, and in order to classify the product the oil is evaluated from a sensorial, chemical and physical point of view.

Oil Storage


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The oil is stored in either underground or above ground tanks. Steel tanks are specifically recommended, preferably placed in areas away from light and air at a controlled temperature.

In order to maintain its characteristic composition in time and space, oil preservation should avoid contact with the worst enemies of fats: light and oxygen.