The production process starts with olive picking which can be manual, by pole–beating or mechanical vibration. The following step is transport to the oil press or mill where the oil will be extracted.

Inside the oil mil olives are separated from branches, leaves and stones which may be mixed with them during the picking process. They are then washed before being milled or ground. Both milling and grinding consist of breaking the olive until it has become a paste which may successively be treated in order to extract the tiny droplets of oil which it contains.

According to the method used, which may be industrial or traditional, oil may be extracted from the paste through centrifuging or compression:

Aceitunas en capacho

  • Traditional method by compression (traditional batch plants). The milled paste is placed between esparto mats and compressed in order to squeeze out its oily juice (a mix of oil and water), which is then decanted in order to make the oil, which has different density, float.
  • Traditional three phase continuous centrifuge system (triple phase continuous plants): one litre of water is added to each kilo of paste and the mixture is put into a horizontal centrifuge, where the solid part is separated from the oily juice. This is then sent to a vertical centrifuge where oil is separated from the vegetable water.
  • Traditional two phase continuous centrifuge system (double phase continuous plants): the process is the same as the previous one, but instead of adding water in the horizontal centrifugation, vegetable water is added. The continuous system, more modern and widespread, avoids olive storage due to the fact that the olives are processed as soon as they reach the plant, making oil quality higher. Furthermore, yields are higher and hygiene and cleaning are improved. The two-phase continuous system doesn’t introduce extra water in the process resulting in higher quantities of polyphenols in the Oil produced.

Aceite de Oliva

Once produced, oil must be stored adequately in cellars, away from light and smells and external elements, at controlled temperatures and in inert containers which do not oxidise. It is normally stored in stainless steel drums until it is bottled.

Once put in its final container, air, and light and heat affect olive oil, so it should always be stored in a closed container, at room temperature and far from direct sunlight.