Unfiltered or Filtered Olive Oil — What Are the Differences? Which Should You Choose?

One of the topics most frequently raised by members of the Mi Oliva Gourmet Club is unfiltered Olive Oil versus filtered: What are the differences? Which should you choose? Which is better for eating raw? Which is better for cooking? And many other related questions.

First of all, it's worth pointing out that an unfiltered Olive Oil is neither better nor worse than a filtered Olive Oil — both retain exactly the same properties, with acidity and organoleptic qualities intact in either type.

Secondly, filtered Olive Oil is what you'll typically find in any shop, supermarket or hypermarket, since filtered oils are by far the most widely distributed. It's very rare to find or buy an unfiltered Olive Oil in those outlets.

There's an added complication too: under current regulations, the label "unfiltered" cannot appear on the packaging, as it is not recognised as an "official" product designation.

That said, it is permitted to include it in the product description, which means that in some physical stores and in all online shops, when you buy an unfiltered Olive Oil, this characteristic does appear in the product description.

In short: if the product description (never the label) doesn't say "unfiltered", you're looking at a filtered Olive Oil. Finally, the production process for "unfiltered" Olive Oil is typically reserved for top-quality Extra Virgin Olive Oils. I have yet to come across an unfiltered Olive Oil that isn't Extra Virgin — though there are plenty of filtered Extra Virgin Olive Oils, filtered Extra Olive Oils and regular Olive Oils, the latter two always filtered.

How is unfiltered Olive Oil made?

To obtain a top-quality Extra Virgin Olive Oil, once the olives have been harvested, they go through a series of manual and mechanical processes — including, for example, a horizontal centrifuge that separates solids and removes impurities. With an Extra Virgin Olive Oil, there are no chemical or thermal processes involved, preserving this freshly made olive juice in its finest form and maintaining all its organoleptic properties, along with the intense, distinctive aroma and flavour that define it.

The final stage of the Extra Virgin Olive Oil production process, before bottling, is filtration. Here, the remaining pulp and olive pit particles are separated from the clean, bright natural olive juice, along with any remaining impurities — achieved through decantation across a series of tanks, where paddles stir the oil over several days. The result is a filtered Extra Virgin Olive Oil of the highest quality, with all its properties and fatty acids fully preserved.

In the case of unfiltered Olive Oil, this process lasts only a few hours, meaning only the heaviest particles settle out, while the rest remain suspended in the oil — there will always be some impurities present. This is what experts refer to as "impurities" in unfiltered olive oils. Historically, this filtration stage wasn't carried out at all, which allowed every nuance of the oil's unique flavour and aroma to come through — which is why, when many of you taste our unfiltered Olive Oil, it takes you straight back to the oil of your childhood: a natural olive juice with a more intense flavour and a wonderfully cloudy appearance 😉

This is precisely why some people prefer not to use unfiltered Olive Oil in a deep fryer — the fact that it contains suspended particles means that, with heat, those particles also settle (forming sediment at the bottom of the fryer). This is one of the main differences between filtered and unfiltered oil.

Personally, I can't stand deep fryers — I'm a frying pan person. So that's not an issue for me. I love using unfiltered Olive Oil for frying, as it never turns black and keeps its qualities intact, because I top it up with each use.

And there's another benefit to the frying pan: it means the oil never reaches very high temperatures, which helps preserve the olive oil and its properties for longer. In a deep fryer, it's easy to push the oil to 180°C or above — and at those temperatures, an Extra Virgin Olive Oil has a shorter useful life, losing many of its beneficial properties, deteriorating faster, and leaving residue at the bottom of the container.

All things considered, Extra Virgin Olive Oil is far and away the best oil to fry with, well ahead of any lower-quality alternative. And it's not just about flavour — if you use it at the lowest temperature possible, especially in a frying pan, it will retain many of its positive qualities and natural antioxidants.

The visible differences between filtered and unfiltered Olive Oil

The key difference between unfiltered and filtered oils is that unfiltered oils contain residual impurities and moisture — tiny particles from the blend of oil and vegetable water that comes directly from the olive itself — since they have not gone through the full filtration process and are not completely free of impurities.

When filtered Olive Oil goes through the filtration process, as mentioned earlier, these small impurities are removed, along with the pulp residue and water particles from the freshly pressed olive juice. The result is a filtered olive oil with a clean, clearer, more golden appearance after decantation.

Unfiltered Olive Oil, by contrast, has a slightly deeper green colour and a cloudy appearance — particularly at the start of the new harvest. When you pour it, you'll also notice it feels slightly thicker than conventional oil, because it contains impurities and suspended particles.

In the bottle or container, unfiltered Olive Oil looks more opaque, less transparent and somewhat cloudy — for the same reason described above.

It's worth noting that, over time, bottled unfiltered Olive Oil undergoes a natural decantation process — the heavier particles gradually settle to the bottom. This also causes the intense green colour to slowly fade, becoming slightly more transparent. This is completely normal: unfiltered oils remain in good condition throughout, with neither the original flavour nor the fatty acids affected — both are preserved intact.

If you'd like to buy an unfiltered Extra Virgin Olive Oil, we recommend our selection of unfiltered oils in the Picual variety. You can place your order in our online shop.

Differences in flavour between unfiltered and filtered Olive Oil

Unfiltered Olive Oil has a slightly more intense flavour than filtered Olive Oil — and that intensity is amplified even further by the visual experience we described above.

Tasting a recipe on a plastic plate is not the same as tasting it at a beautifully laid table. Our minds prime us to savour, to pick up on nuances and aromas that we might otherwise miss entirely.

Picture yourself pouring a PDO unfiltered Extra Virgin Olive Oil of the Picual variety — almost as if it were freshly pressed — with that colour, that intense aroma and flavour, that dense texture as it slides slowly over a gorgeous slice of sourdough, its scent as fresh as possible carrying you straight to the purest olive groves and the diatomite soils that nurture this treasure, filling every sense, alongside a cold glass of orange juice… My mouth is watering just thinking about it — is yours?

Tasting an unfiltered oil is simply not the same as tasting a filtered one. Sure, the experts say there's barely any difference in flavour between an unfiltered Extra Virgin Olive Oil and a filtered one — but of course, they "taste" it by sipping from a small opaque glass, seeing nothing of its colour, its texture, any of it… Their loss!

The truth is, the reviews our customers leave on our website speak for themselves. Here are the most recent ones — and after that, I'll explain how to store unfiltered Olive Oil properly:

How should unfiltered Olive Oil be stored?

Because unfiltered Extra Virgin Olive Oil contains small amounts of suspended particles that naturally settle over time, we recommend following these tips to get the most out of it:

• Keep the oil in its original box, unopened and closed, to protect it from light.
• Store the box in a dry place at a cool, stable room temperature, away from significant temperature fluctuations.
• Once you open a container — especially a 2 or 5 litre one — consider decanting the oil into a smaller, ideally stainless steel vessel. This way you can use it daily without repeatedly opening and closing the original container. Your oil will keep all its aromas, properties and fatty acids in the best possible condition — every time you use it, it will taste as though the olives were just pressed.

Following these tips keeps oxidation to a minimum, allowing you to maintain the oil in perfect condition for up to a year — provided it is consumed regularly and kept at the right cool room temperature. You should also always check the best-before date on the packaging.

As you can imagine, none of this happens in a supermarket. The oil sits exposed to light and constant temperature changes, meaning both unfiltered and filtered Olive Oil lose many of their properties over time. Our customers notice the difference — and the advantages of the extra virgin olive oil we offer them.

At Mi Oliva Gourmet we bottle in small batches — once a month, sometimes even less — which means our unfiltered and filtered oils are always freshly bottled, all year round. They are among the finest Picual variety extra virgin olive oils on the market.

And where are they stored in the meantime? In our Olive Oil Mills, at a constant temperature and humidity, inside sealed stainless steel tanks — conditions that help preserve the oil in a far more stable environment.

In other words, handled with the utmost care. Why? Because it's far cheaper to do what the big retailers do: buy batches of millions of litres and store pre-bottled filtered oils in logistics centres. And that's precisely why those large retailers rarely stock unfiltered oils — and why extra virgin olive oil prices vary so widely on the market.

If you know us and are already one of our customers, you know that we love our land and our oil — and above all, we know that you value this "green gold" of ours just as much as we do, if not more. We would never treat it any other way.

Well, dear Extra Virgin Olive Oil lover, I hope this has answered your questions — and I encourage you to try one of our unfiltered Extra Virgin Olive Oils from our latest harvest:

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