Short answer: always choose filtered extra virgin olive oil.
To understand why we recommend this, we first need to understand how extra virgin olive oil (EVOO) is produced.
What is filtration, and what is it for?
Olives brought to the mill on the day of harvest are crushed and then malaxed until a homogeneous paste is obtained (preparation phase for producing olive oil). This paste therefore contains all the elements that make up an olive, i.e.:
- its solid elements (skin, pit), and
- its liquid elements (oil and water, known as "vegetation water")
Subsequently, this paste will undergo 2 centrifugation processes:
- a "horizontal" one to separate solids (skin, pit) from liquids (oil & water), and
- a "vertical" one to separate the liquids from each other (oil & water).
However, this process is not enough to completely eliminate impurities (micro-residues of pit and skin).
These impurities, in the days and weeks to come, will accelerate the degradation of your olive oil. To guarantee the stability of the oil over time (just after extraction and well before bottling), it is highly recommended to filter the olive oil. This filtration protects the olive oil against oxidation and helps maintain its quality for the next few months after its production.
Unfiltered extra virgin olive oil: The TrendUnlike filtered olive oil, unfiltered olive oil is bottled directly after extraction, meaning without having removed the vegetable particles. Its marketing presentation appeals to some consumers who see it as a more "raw & authentic" product. But unfiltered olive oil degrades more quickly over time and is more "vulnerable" to oxidation, which will subsequently cause the oil to go rancid, an unpleasant sensation and also one of the defects of olive oil - and thus your oil will no longer even be an extra virgin olive oil!
If you absolutely want to experience unfiltered olive oil, I advise you to do so until Saint Nicholas Day (December) or at most until Epiphany (early January) - so generally 1 to 2 months after its harvest and production. Compare that to 12 to 18 months for filtered olive oil...
With Ad Olivetum, I only offer filtered olive oils.
Because a filtered oil, on the other hand, exhibits much greater stability. It keeps better over time, is more resistant to oxidation, but requires the same particular precautions for its storage. Over time, filtered olive oil also better maintains its polyphenol content.
The process described (very briefly above) explains why we now say that oil is extracted - and not that olives are pressed (another unfortunate marketing term). Regarding virgin olive oil, all these actions are purely mechanical and no chemical process is involved at any time.
