The Olive Oil Production Process

  • The production process of olive oil in the Iberian Peninsula is ancient, though it has undergone many changes up to the present day. 
  • Olive oil is the only fat in the world obtained by mere pressing, without additives or other chemical instruments.

From the Seed to the Mill

We all know that olive oil is a key food for human nutrition. Its health benefits are countless, and its consumption has skyrocketed in recent years, reaching every corner of the world. The origin of olive cultivation in the Iberian Peninsula dates back centuries before Christ, in the Roman era. Even then, it was a commodity of great interest that boosted trade in the region and eventually became a symbol of Spain and, particularly, Andalusia.

The olive oil production process is a cycle that lasts practically all year, as nowadays every detail is meticulously cared for to achieve the highest possible quality final product. Olive oil is logically obtained from the fruit of the olive tree, but there is a wide variety of olives in the Iberian Peninsula, so it is interesting to know the origin of the oil to distinguish its characteristics beforehand. Some of the main Spanish varieties are known as picual, manzanilla, hojiblanca, or lechín.

The olive tree is a very long-lived tree but grows slowly, so it is not common for it to begin bearing fruit before five years from planting. This figure depends on factors such as soil, climate, variety, or care, although it is very difficult to achieve in less time. As for the harvest season, it should be noted that the best time is generally late autumn or early winter. The techniques for harvesting olives are varied, ranging from manual to automated, including branch beating (“vareo”) or machine shaking.

Olive oil production process.
Olive harvesting with advanced machinery.

Olive oil production process

Once harvested, the olives are transported to treatment plants known as mills, where they will be prepared for packaging. This transport must be swift so that the olives do not lose their properties. Once again, the care of the product is as important as the quality of the fruit. Thus, in the mill itself, the best olives are selected, discarding those less suitable for consumption or those with imperfections. Likewise, residues such as leaves, branches, or soil are sieved and removed.

The selected olives are then ground to start releasing oil. The result of this step is the creation of a paste that is almost ready to become the virgin oil we know. However, this paste still contains some non-oily product, known since Roman times as “amurca,” which is separated from the oil in a centrifuge. The resulting oil only needs to be decanted to remove suspended particles, while the rest of the paste can be centrifuged again to obtain what is known as pomace oil.

Extra virgin oil is obtained directly without any extra treatment, although there are other types of oil depending on the heat applied to the fruit. Once the olives are ground, before extraction, the paste is kneaded at a determined temperature. When this temperature does not exceed 27 degrees Celsius, it is considered a “cold” production, resulting in these virgin and extra virgin oils. The difference between these two oils lies mainly in acidity: while extra virgin does not exceed 0.8 degrees, virgin has a margin of up to 2 degrees. Once the oil is obtained, it is packaged for distribution and sale to the consumer.

Packaging and Types of Oil

The olive oil production process is natural and straightforward. In some cases, once produced, it requires storage before packaging. This storage usually occurs in cellars and stainless steel oil tanks, at a temperature that should range between 15 and 18 degrees Celsius. Stainless steel maintains all the properties of the oil and protects it from external factors that can degrade its quality, such as heat, sunlight, or air.

When packaging for sale is decided, it is commonly done in glass, plastic, or metal containers. It is recommended that, even though it is packaged, it should be protected from the previously mentioned factors. This keeps the oil in optimal conditions and allows it to last for years without being consumed. Indeed, it is a product that does not expire, although it undergoes changes over time. In fact, the dates on oil containers indicate the best-before date, not the expiration date, so its consumption afterward only results in a loss of vitamins and properties, not other more harmful effects like intoxication.

In addition to extra virgin olive oil and regular virgin oil, there are other olive oils with a slightly extended process. This is the case with pomace oil, which comes from the paste used to produce extra virgin and requires further refining for its production due to the inclusion of skin, pits, and pulp of the olives. Being refined and mixed with virgin oils, pomace oil ends up acquiring properties that many experts still consider superior to other seed oils, such as sunflower oil.

Olive oil production process
Olive oil storage.


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