Cold extracted olive oil is olive oil extracted at a temperature below 27 °C (80 °F).
In the production of Extra Virgin Olive Oil, once the olives are crushed at the mill, the resulting paste is gently heated during kneading, as this encourages the small droplets of olive oil in the paste to combine, increasing the efficiency of the extraction process.
Nevertheless, temperature has a significant impact on the final quality of the olive oil from both a culinary and an organoleptic point of view.
The compounds responsible for the aromas and flavors of olive oil are volatile, which means they evaporate easily. Therefore, the higher the extraction temperature, the more volatile compounds are lost. As a result, the olive oil loses intensity of aroma and flavor, and its culinary qualities are reduced.
This information is particularly relevant for high-quality Extra Virgin Olive Oils, which are often consumed raw.
On the other hand, low temperatures reduce the rate of oxidation of the olive paste, so, under the same conditions, cold extracted olive oils will have lower acidity.
As an interesting fact, this process, taken to the extreme, is one of the steps in refining pomace olive oils, where the oils are heated to temperatures above 150 °C. In this case, the purpose is not to increase production but to eliminate the unpleasant flavors and odors of pomace olive oils.
There is considerable confusion about the concept of cold extraction. In some forums, we have read that only cold extracted Extra Virgin Olive Oil is genuine, or that it contains the highest levels of polyphenols, antioxidants, and anti-inflammatory compounds. This is not true. There are Extra Virgin Olive Oils that, although they have not been produced under cold extraction conditions, still meet all the requirements to be classified as Extra Virgin. If they meet the acidity requirements and the organoleptic standards established through sensory evaluation, they are classified as Extra Virgin Olive Oils.