Who of you have not stood in front of numerous bottles of Olive Oil, thinking, what on earth does all this mean and which one must I buy? I was one of those until a Greek friend of mine explained the method behind the madness!
Olive Oil, Which One?
What is the difference between cold pressing and cold extraction?
An indication that is often bamboozling is the difference between cold pressing and cold extraction.
'Cold extraction', refers to virgin or extra virgin olive oils procured at a temperature below 27 degrees Celsius, by percolation (filtration, separation) or centrifugation of the olive paste. The olives aren't pressed as such but rather extracted by a centrifuge. The term "cold extracted" is used for olive oil that is pressed with a traditional hydraulic press.
For 'cold extraction' to happen, it is necessary to implement the adequate technology at the oil mill in order to ensure that the temperature of 27 degrees Celsius is not exceeded throughout the whole extraction process. The components of the oil which are responsible for the characteristic aroma and scent are unchanged. If the cold extraction did not take place, these components would disappear.
Cold extraction technique means a lower production for the same amount of olives but a much higher quality of the oil. Cold extraction ensures the highest quality for extra virgin olive oil.
Extra Virgin Olive Oil
Extra-virgin olive oils are obtained at a temperature below 27 degrees Celsius from the mechanical pressing of the olive paste by a traditional extraction system using hydraulic presses.
Extra-virgin olive oil is always cold extracted or pressed, but a cold extracted or pressed olive oil is not necessarily extra virgin.
"First cold pressing" an indication no longer allowed on labels. With present-day techniques, it is not necessary to press the olives various times to extract all the oil.
Image credit
Another interesting issue concerns “first cold pressing”, an indication no longer allowed on the labels. With present-day techniques, it is not necessary to press the olives various times to extract all the oil.
Millstone
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The modern technique of olive oil extraction uses an industrial decanter to separate all the phases by centrifugation. The olives are crushed to a fine paste. This can be done by a disc crusher, hammer crusher, depitting machine or a knife crusher. The paste is then pumped into an industrial decanter. The paste is spun in a centrifuge to separate the oil.
Acidity
The lower the temperature the lower the acidity which leads to a high-quality oil. Acidity is the weight ratio of free oleic acid in comparison with the total quantity of oil. This is an important aspect of olive oil.
Let your tastebuds lead you!
Source:
https://www.brainstuffshow.com/blogs/how-to-make-olive-oil.htm
https://www.oliveoilsource.com/page/making-olive-oil
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