How Olive Oil is Made


The production of olive oil requires a great deal of patience and diligence. Trees must be pruned, irrigated, and monitored for pest activity while the fruit is developing. Next comes the critical moment of deciding when to harvest. Traditionally, people wanted the highest possible yield out of their crop, so they waited until the olives were quite ripe before harvesting them. While this can offer more quantity, the olive oil—due to the loss of polyphenols as the olives ripens—is more unstable, less nutritious and of lower quality. Striking at the right moment for harvesting is key for making excellent extra virgin olive oil. We here at Pacific Sun Farms tend to mill greener olives in order to maximize polyphenol extraction.

More than two thousand years have elapsed since Cato wrote “De Agricultura.” Since then, much new knowledge has become available, and the quality of most oils have improved immensely. However, the unchanging golden rule for making olive oil is that the olives should be harvested and milled immediately. It is our desire to make a high quality, healthy, and fresh tasting olive oil.


When harvesting to make olive oil, olives are harvested based on the ripeness needed to achieve the highest quality oil. For us, this requires an important antioxidant count as well as a flavor profile characterized by freshness and a harmonious presence of perfumes, bitterness and pungency. Harvesting olives is done by hand shaking and, more recently, some mechanical harvesters. Swatting the olives is altogether not recommended since it damages the olives. After the olives are harvested, they are placed in wooden or plastic bins and delivered to the mill. The faster the olives are processed the better. The olives should be milled ideally within twelve hours or less of harvesting.


Once the bins containing the harvested olives have been loaded onto a truck, we transport them to the olive mill and begin producing Pacific Sun Farms Olive Oil. Monitoring the temperature of the olives is a very important factor when making EVOO. For this reason, and because of the warmer autumns we’ve been having lately, we have added a cooler to our mill, where the olives are placed right after they are harvested. Once they are at 16C/17C (around 60–65F), we use a forklift to place a full bin on the bin dumper. The bin dumper, powered by a hydraulic lift, then dumps the bin into a hopper that is covered by a grate that serves as the first screening mechanism for the mill. From the hopper, a conveyor belt carries the olives in small, manageable loads into the washing tank. The conveyor belt then drops the olives across a blower.

Lighter materials like leaves and twigs are blown out of the system, while the heavier olives pass through the blown air and into the tank. The washed olives then pass down one last grate, across one last screen, and into the awaiting hopper.

Next, the freshly washed olives go under a blower to remove the water from the washer. Directly after that they go into a new generation crusher.

Traditionally, mills were equipped with hammer-mills, and a vast majority of them still are today. There is a long list of drawbacks to the way hammer-mills crush olives, including increased heat, emulsion, and very importantly, the activation and dispersion of negative enzymes contained in the pit.

Because our new crusher does not use hammers to turn the olives into paste, there is a more gentle crushing process that keeps temperatures down and diminishes emulsion. This new crusher works with blocks that have very sharp edges, slicing the olives instead of pulverizing them. This process results in a shorter malaxing time. Pits also break down more gently, diminishing the triggering of enzymes that have a negative action. Another interesting feature of this crusher is an inverter, which allows for higher or lower crushing speeds—which we can adjust based on cultivars, ripeness and tasting profile.

The paste that is created by the crusher is sent through tubes into the malaxer where it is mixed by two corkscrews. We minimize the time the paste stays in the malaxer as much as possible because while the paste is moved, and naturally warmed an undesirable oxidation takes place. Again, this aspect of our Pacific Sun Farms milling process favors quality over quantity.


The mixed olive mash is passed from the malaxer into the two phase centrifuge. Here it is spun through a series of cylindrical grates. Oil and water are spun out of the mash, which is then spun a few more times before it leaves the system. Olive mash enters the system and then oil, water and mash separately exit.

Both the oil and water pass through the vertical separator, which further separates the two from each other. The oil leaving the vertical separator is free of water and all but the smallest particles left from the mash.


As the olive oil leaves the vertical separator, we filter it. The practice of filtering olive oil—still not used by most producers in California—ensures the quality of the oil and creates an oil with a longer, more stable shelf life. In order for filtration to be successful, it should be done within 48 hours or less.

The International Olive Council (IOC) has established that the water content of olive oil should be less than 0.2% in order to have a good shelf life. That low percentage is best attained with filtration.

While this is more time and labor intensive, we know it is necessary for reaching the quality of oil that we, and our customers, desire.

Read more information about why we filter our olive oils…