Extraction of olive oil
Contrary to popular belief, olive oil is not typically “pressed”. Rather, the oil is extracted from olives using modern equipment. Modern olive oil extraction processes result in high-quality olive oil and better yields from the fruit. Read on to learn more about how olive oil is obtained.
Here's a breakdown of what's shown in the graphic above
After the olives are prepared for extraction, they are crushed or ground using mills or grinders. The mills can be stone or metal hammer mills.
The olive paste is placed in a malaxer, which is a trough with spiral mixing blades. The temperature in the malaxer is monitored to ensure the olive paste is not heated above 27°C (80.6°F). Malaxation lasts 20-45 minutes.
Separate solids and water from olive oil
After malaxation, the mixture is sent to a centrifugal extractor. The aim is to separate the pomace (skins, pits and olive solids) from the oil.
The olive oil can be sent to another separator that spins the olive oil and removes any remaining water from the olive oil.
Why is olive oil no longer pressed?
Traditionally, the olives were ground with stones and the paste then pressed on straw or jute mats. In modern times, a metal hydraulic press can be used to press the olive paste. However, most manufacturers have switched to centrifuges.
If presses don't exist, why is extra virgin olive oil sometimes still referred to as "cold pressed"? Cold pressed is a marketing term for which there is no regulated definition. According to the International Olive Council, all extra virgin olive oils are extracted at temperatures below 27 °C (80.6 °F). So, by definition, all extra virgin olive oils are “cold pressed” or “cold extracted”.
Image credits: This image was created during the Density Design Integrated Course Final Synthesis Studio at Politecnico di Milano, organized by DensityDesign Research Lab. The image is released under the CC-BY-SA license. Attribution goes to Cecilia Della Longa, DensityDesign Research Lab. - Own work, CC BY-SA 4.0, Link