Olive oil, filtered or unfiltered? What's the difference and how to choose?

Unfiltered extra virgin olive oil tends to have a more intense, fruity aroma and retains a higher concentration of natural olive compounds. It’s often described as more raw and expressive in character. However, it has a shorter shelf life and is more prone to spoilage or fermentation, particularly if not stored properly. Over time, sediment may appear at the bottom of the bottle, which is normal but can affect the oil's stability.

Filtered olive oil, on the other hand, offers much greater stability. It keeps better over time, is less vulnerable to oxidation, and doesn’t require any special storage conditions. That said, some antioxidants are lost during filtration, and the flavour may be slightly less intense compared to unfiltered oils.

Unfiltered extra virgin olive oil hasn’t gone through the usual process that removes small plant particles and residual water. It’s more raw, more intense, and offers a unique sensory experience — but it also requires special care.

What is filtration, and what is it for?

Olives brought to the mill on the same day they are harvested are crushed and kneaded into a homogeneous paste. This paste contains oil, what's known as vegetation water (naturally present in olives), and solid parts such as the pit and skin. The paste then undergoes two centrifugation steps: a “horizontal” one to separate solids from liquids, and a “vertical” one to separate the liquids — olive oil from vegetation water. Since this is virgin olive oil, all operations are strictly mechanical, with no chemical processes involved at any point.

However, this process isn’t enough to completely remove impurities such as microscopic bits of pit and skin. In the weeks that follow, these remnants can accelerate the degradation of the virgin olive oil. To ensure better stability over time, it’s strongly recommended to filter the oil before bottling. Filtration helps prevent fermentation and oxidation, though it causes a very slight loss of oil.

Is the flavour really better without filtration?

One of the arguments in favor of unfiltered oils is their aromatic intensity, often described as more “fruity” or vibrant. But keep in mind: this character can also come from well-made early harvest oils — even when filtered.

Olive oil is not like wine: it begins to deteriorate from the moment it’s produced, and organic residues only speed up this process. That’s why proper storage is crucial, especially for unfiltered oils.

How should unfiltered oil be stored?

If you go for an unfiltered oil, make sure to consume it quickly once opened, and store it away from light, heat, and air. Over time, you may notice sediment forming at the bottom of the bottle — this is natural, but if left too long, it can affect the oil’s stability.

Our recommendation:

If you want to try unfiltered extra virgin olive oil, make sure your in the presence of fresh olive oil (harvested generally in October/November), and then do so no later than early January. Use an opaque container (never a clear bottle),and be especially careful with storage — the container must be tightly closed, away from any heat source, and protected from direct light.

As a general rule, we recommend choosing filtered extra virgin olive oil :)

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unfiltered olive oil at the mill

unfiltered early harvest olive oil

at the mill: decanter to separate solids and liquids

at the mill: decanter to separate liquids (water and olive)