When referring to olive oil being produced "solely by mechanical methods," it means that the oil is extracted from the olives without the use of chemicals or solvents, and without excessive heat that can degrade the oil's quality. Here are the primary mechanical methods used in the production of olive oil:
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Crushing: The first step in the process is crushing the olives to form a paste. Traditionally, this was done with stone mills, but modern facilities might use metal tooth grinders or hammer mills. The goal is to break down the cell walls of the olive fruit to release the oil.
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Malaxation: After crushing, the olive paste is slowly churned or mixed. This process, called malaxation, allows the small oil droplets to agglomerate and form larger oil droplets, making the subsequent extraction more efficient. It's crucial to manage the temperature during this phase to ensure the oil retains its quality.
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Centrifugation: The malaxed paste is then transferred to a centrifuge. The centrifuge spins the paste at high speeds, separating the oil from the solid pomace and the water. There are two main types of centrifuges used: the three-phase (which separates oil, water, and pomace) and the two-phase (which separates oil and a wet pomace).
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Decanting: After centrifugation, there might still be some water remaining with the oil. The oil is allowed to settle, and the water (which is denser) settles at the bottom. The oil can then be decanted or separated from the water.
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Filtration: To remove any remaining impurities, particles, or water, the oil might be filtered. This step is optional, and some producers might skip it to retain a more robust flavor or if they believe the filtration process might remove beneficial compounds.
These mechanical methods are physical processes that don't alter the chemical structure of the oil. They ensure that the oil remains in its most natural state, preserving its flavor, aroma, and nutritional properties.
