Malaxation

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Malaxation is one of the unit process of Olive oil extraction.

Malaxation is the action of slowly churning or mixing milled olives in specially designed mixer for 20 to 40 minutes. This mixing allows the smaller droplets of oil that were released by the milling process to combine into larger ones which can be more easily separated. The paste is normally heated to around 27º Celsius during this process. Oil yield is directly proportional to the temperature and mixing time. However, the use of higher temperatures and longer mixing times increases oxidation of the oil and therefore decreases shelf life, so a compromise must be struck. Also, the usage of higher temperatures does not allow for the labelling of the oil as "cold extracted", a term used widely as a marketing tactic, especially in the European Union.

It is now possible, with newer equipment, to use a blanket of inert gas such as nitrogen or carbon dioxide over the olive paste, which greatly reduces oxidation. This allows for an increased yield without compromising the quality of the oil.

After malaxation is finished, the paste is then sent to a phase separator. Nearly all producers use a decanter centrifuge for this next phase.

Traditionally the olive oil was removed from the paste using a large press that was either screwed down or levered down with a load of rocks.

Malaxation

See also