Once the olives are harvested, time is of the essence. Ideally, olives should be pressed immediately after the harvest so as to preserve their flavor, aroma, and nutrients. Olives that are left out for days or weeks lose their character and produce poor tasting olive oil. 

The first step in the oil extraction process is to separate the leaves, twigs and and stems from the fruit. The fruits are then washed to remove any remaining sediment or dirt. 

The second step is crushing the olives into a paste. The purpose of crushing is to tear the flesh cells to facilitate the release of the oil from the vacuoles. 

Malaxing (mixing) the paste for 20 to 45 minutes allows small oil droplets to combine into bigger ones.  It is an indispensable step. 

The next step consists in separating the oil from the rest of the olive components. This used to be done with presses but is now done by centrifugation.  

(Cold pressed or Cold extraction) means that the oil was not heated over a certain temperature (usually 80 °F (27 °C)) during processing, thus retaining more nutrients and undergoing less degradation. First cold pressed means “that the fruit of the olive was crushed exactly one time. The cold refers to the temperature range of the fruit at the time it is crushed. Industrial olive growers will use heat and chemicals to extract the oil, which yields greater volume, but destroys the nutrients and flavor. )

Some centrifuges are called three-phase because they separate the oil, the water, and the solids separately. The two-phase centrifuges separate the oil from a wet paste. In most cases, the oil coming out of the first centrifuge is further processed to eliminate any remaining water and solids by a second centrifuge that rotates faster. No heat or chemicals are used during the centrifugation process, thus allowing the oil to retain its nutrients and flavor. 

In order for the olive oil to retain the highest level of quality, it should be separated from any sediment and water remaining after extraction. This process is called racking, which pumps the oil from the top of the yield into a clean container, leaving the sediment and water at the bottom.