Many terms related to the world of olive cultivation are now familiar to you, such as “cultivar” or “taggiasca,” but many other expressions are less known, even though they are very important for identifying the quality of a extra virgin olive oil.
In the glossary of an attentive person, the term “cold pressing” cannot be missing. Let’s discover together what it hides.
Definition of cold pressing
The term cold pressing or cold extraction refers to the production of vegetable oil, such as extra virgin olive oil, which is carried out through a mechanical process.
To appropriately use the term cold pressing, the temperature at which the extraction takes place must be below 27°C for extra virgin olive oil only, while for other vegetable oils it is significantly higher.
What you need to know about cold pressing?
The important thing to know about cold pressing is that this technique allows to maintain the physical and nutritional characteristics of extra virgin olive oil, ensuring not only that the organoleptic properties remain intact but also guaranteeing all the benefits that can be derived from its daily consumption.
Cold pressing is so named because of the temperature of the paste of crushed olives which must not exceed 27 degrees during the malaxation, one of the phases of oil production that we discussed in a previous article.
Cold pressing involves the crushing of olives using two different methods:
- traditional technique, through the rotation of large stone wheels (granite) on the olives, which will then be pressed
-
modern technique, through the use of mechanical crushers in continuous cycle and decanters.
This latter is the most commonly used method because it improves the hygienic standards of the products made and thus aligns with the needs of consumers and the market.
Thus, cold pressing allows for the extraction of the content of the drupes without altering the amount of minerals, vitamins, and substances rich in antioxidant properties – that they contain – which are useful for our body.
The main phases of pressing, all carried out with mechanical methods, are:
- washing
- grinding
- malaxation
- pressing
- centrifugation
- filtration
Differences with hot pressing
There is obviously also hot pressing, which involves the use of heat points during the phases of malaxation, extraction with the decanter, and washing of the presses after pressing.
Heat improves the extraction of the oil, which will be greater in terms of quantity, because it promotes the union and thus the accumulation of oil particles, but the quality undoubtedly suffers; the oil becomes more fluid, but at the same time, the processes of deterioration and oxidation will occur more quickly. The organoleptic properties also suffer: the oil loses some of the bitterness and pungency that characterize it and tastes sweeter.
Errors to avoid
It is important to emphasize that the term “cold pressing” on the label is often incorrectly associated with the simple method of crushing olives, and there is also a tendency to believe that pressing done with stone mills better preserves the properties of the oil compared to that done with mechanical crushers. All incorrect!
A mechanical crusher can ensure low temperatures but does not heat the oil paste, and it also allows for compliance with hygiene standards during production.
One must never confuse cold pressing, which refers to the maximum temperature that the oil paste can reach – the lower it is, the better the properties of the oil are preserved – with the crushing method which can occur with stone mills or mechanical hammer crushers.
Sometimes you may read on oil bottles the phrase “first cold pressing,” which implies that a second is also expected. This is simply misleading, as today’s processing techniques no longer require the presses to be operated twice, as was the case in the past. Therefore, nowadays it would be more appropriate to use the simple term cold pressing.
Cold pressing, an effective and healthy processing method
This technique ensures a production method capable of enhancing the qualities and sensory and organoleptic characteristics of the extra virgin olive oil. Moreover, the consumption of oil produced this way ensures truly unique nutritional values and benefits for our health.