Unfiltered extra virgin olive oil is freshly extracted EVOO that has not undergone a filtration process, retaining microparticles of olive pulp, skin, and plant water. Its cloudy appearance may seem more "natural," but it hides a problem that few people tell you about: those particles ferment. And when they ferment, the oil spoils. At Molino y Cata, we do not sell unfiltered oil, and in this article, we explain exactly why.
TL;DR: Unfiltered EVOO—also called olive oil in branch or cloudy oil—contains water and organic matter residues that ferment over time. Filtering costs money (cellulose plates, a 3-5% product loss), so selling it unfiltered is, in many cases, a cost-saving measure disguised as a premium product. When consumed very fresh and raw, it can be an interesting experience, but its useful window is weeks, not months.
What "unfiltered" means (and why it's not what you've been sold)
Unfiltered oil is oil that goes directly from the decanter—the machine that separates the oil from the water and pomace—to the tank or container, without passing through a filter of cellulose plates and diatomaceous earths.
It retains between 1% and 3% suspended particles: plant water, microscopic fragments of olive skin and pulp. Those particles are responsible for its cloudy appearance, and also for its main problem: they contain sugars and organic matter that begin to ferment as soon as the temperature rises or days pass.
Remember: decanting itself is already a first separation. Only the fat fraction leaves the decanter, leaving behind the alpeorujo and most of the water. So when someone says "unfiltered oil," we are not talking about a raw product. We are talking about an oil that has skipped a step. And that step has a cost that someone has saved.
Olive oil in branch, cloudy oil, new oil: different names, same problem
If you have heard of olive oil in branch, it is the same product. It is the term used by olive mills to refer to freshly milled oil without filtration. In Italy, they call it olio nuovo. In colloquial language, many consumers know it as cloudy oil, because of its opaque appearance.
All these names describe the same thing: EVOO that goes directly from the decanter to the container without passing through a filter. It doesn't matter what you call it. What matters is what happens inside that bottle as days pass.
I didn't know this about unfiltered oilWhat no one tells you: filtering costs money
Now think like a producer. Each cellulose plate for the filter costs between €3.50 and €4. A plate filter has between 40 and 60 plates, which must be changed approximately every 500-700 kg of processed oil. Do the math: just in plates, we are talking about €140 to €240 for each filtration cycle.
And that's not all. In the filtration process, between 3% and 5% of the oil is lost, which remains retained in the plates. If you filter 1,000 liters, you lose between 30 and 50 liters. At current prices of quality EVOO, that is hundreds of euros that stay in the filter.
So when you are sold unfiltered oil as something more "natural," more "authentic," or more "premium"... think about what has really happened. You think you are buying something better. But in many cases, you are buying an oil that has saved a production cost and had its price increased.
Not all producers who sell it this way do so for this reason. There are honest olive mills that offer oil from the current campaign for immediate consumption, and that has its value. But the marketing of "unfiltered = better" is, at least, a half-truth.
What about polyphenols? Let's look at the data
This is the argument that is repeated the most: "unfiltered oil has more polyphenols." And it is partially true. By not passing through the filter, an additional proportion of polyphenols dissolved in the plant water is preserved. The non-polar ones—those in the fat—remain the same in both cases.
How much more? The difference is modest. A good filtered early harvest EVOO can exceed 400-600 mg/kg of total polyphenols. What is provided by the retained water is little compared to much more determining factors: the variety (Picual has more than Arbequina), the time of harvest (green has more than ripe), the altitude of the olive grove (above 400 meters, more concentration), and the milling speed.
After years training professional tasters at the University of Jaén, I am clear: the variety, the time of harvest, and the fast cold milling are what really make the difference. The retained water provides a little more polyphenols, yes, but it is the cherry on top, not the cake.
The EU allows declaring on the label that "the polyphenols of olive oil contribute to the protection of blood lipids against oxidative damage" when the oil exceeds 250 mg/kg (EU Regulation No. 432/2012). The PREDIMED study (2013) linked the habitual consumption of high-polyphenol EVOO with a significant reduction in cardiovascular risk.
But here comes the twist: those extra polyphenols from the unfiltered oil last for weeks. Because the same water that retains them is the one that causes fermentation. Researchers from the UC Davis Olive Center summarize it like this: the suspended solids in unfiltered oil contain water and enzymes that deteriorate the stability of the oil, accelerate fermentation, and degrade its sensory quality (Filter or not? A Review of the Influence of Filtration on Extra Virgin Olive Oil, 2015).
A study by the IFAPA (Andalusian Institute of Agricultural Research and Training), presented at the XVII Scientific-Technical Symposium of EXPOLIVA, confirms it for Spanish varieties: prolonged storage produces a general decrease in fruity, bitter, and spicy attributes, and unfiltered oils show a lower intensity of fruitiness compared to filtered ones. In other words: filtered oil preserves its sensory and bioactive characteristics better over time.
So the question is not "which one has more polyphenols on day 1?". The question is "which one will have more polyphenols when you eat it?". And the answer, unless you drink it the same week, is filtered.
Filtered oil vs. unfiltered: the real table
| Characteristic | Filtered | Unfiltered |
|---|---|---|
| Appearance | Clean, bright, translucent | Cloudy, dense, opaque |
| Polyphenols on day 1 | Slightly lower | Slightly higher |
| Polyphenols at month 3 | Stable | Degrading due to fermentation |
| Optimal shelf life | 12-18 months (Quality Picual) | 2-4 weeks at full peak |
| Stability | High — no fermenting particles | Low — sugars + water = fermentation |
| Production cost | Higher (filter + 3-5% loss) | Lower (skips filtration) |
| Risk of defects | Low if stored well | High as weeks pass |
| Ideal use | Daily cooking, frying, storage | Only raw and only if very fresh |
| Quality | EVOO if it passes the tasting panel | EVOO… until it ferments |
The conclusion is clear: unfiltered oil can be a spectacular sensory experience if you try it freshly extracted, at the olive mill itself, during the campaign. But as a shelf product with weeks or months of life, it makes no sense.
The test: what happens when you store an unfiltered oil
In our olive oil shop we have done the test many times: two bottles from the same campaign, one filtered and the other unfiltered. The filtered one holds up perfectly for a year, clean and stable. The unfiltered one accumulates sediment at the bottom in a matter of weeks, and every day that passes, it ferments a little more.
It is not an opinion: the International Olive Council (IOC) itself, the intergovernmental reference body of the sector, recommends that olive oil be subjected to filtration to remove solid microparticles and water, because that increases its shelf life and stability.
An extra virgin olive oil, remember, cannot present any defect in sensory analysis. If fermentation advances, that oil becomes virgin. Or worse. If you are not clear on the difference, take a look at the complete classification of olive oils.
So, when does unfiltered oil make sense?
Let's be fair: there is a time and a place to try it. If you are at an olive mill during the campaign (November-January), and they offer you freshly extracted oil directly from the tank... do it. It is an experience you cannot replicate with a bottled filtration. The aromatic intensity, the body, that explosive green, the notes of fresh cut grass and tomato. It is olive oil in its rawest form.
But that is a moment. It is not a shelf product.
If you see an unfiltered oil in a supermarket or in a supposedly specialized store, under fluorescent lights, without a visible milling date, with weeks or months since it was bottled... pass it by. What you are seeing is not a premium product. It is an oil that is spoiling while you look at it.
Do you want to know how to choose a good extra virgin olive oil? Do not look for cloudiness. Look for harvest date, variety, acidity, and producer. That is what matters.
What oils are better than an unfiltered or olive oil in branch?
If what you are looking for in olive oil in branch is intensity, freshness, and polyphenols, there is a way to have it without the clock ticking against you: a filtered extra virgin, from an early harvest and from a variety that concentrates them. These three are the ones I would put on the table.
MOCA — is our oil, a Picual from Jaén. Perfect if what you are looking for is a great selected format as we select an early harvest or high-end. We have put it on sale after years of selecting the best EVOO from Spain, because we were missing one that represented what we believe: that a true extra virgin should be in every kitchen and not just in those of enthusiasts. Real quality at a price that allows using it daily, not saving it for guests. It is the one we have at home and the one we use every morning.
Oro del Desierto Picual — organic from Almería, with three consecutive golds in New York. It is the Picual I bring out in tastings when someone wants to understand what terroir is: same DNA as any other Picual and a completely different result. On the nose, olive leaf with green apple, almond, and banana peel; at the end, a black pepper that leaves your mouth alive. The Alonso family has been producing for three generations under conditions that many would consider impossible, and the lack of water concentrates the aromas in a brutal way. It is the oil that proves that the olive tree, when it suffers, grows.
6 de Octubre Picual — regenerative organic from the Granada Altiplano, with an unusual fineness: very clean green fruitiness, almond and fresh grass, with the bitterness and spiciness in balance and a long finish. Maikel Lara brought it to the store, we tasted it, we didn't believe it and we insisted that he present it at the awards; it entered the TOP 20 of limited production of EVOOLEUM and the TOP 10 of Iberoleum. Behind it is AlVelAl and its certified regenerative agriculture, which cares for soil, water, and biodiversity. Raw, on a piece of toast with a pinch of salt, it is an everyday luxury.
All three are Picual—the variety that concentrates the most polyphenols—early harvest and filtered. That is: everything that is attributed to the cloudy oil, and it lasts.
In our olive oil shop in Granada, where I personally select every reference, we work exclusively with maximum quality filtered EVOO, from producers who invest in filtering well because they want their oil to reach your table in the best conditions. During the campaign, if you come to the store, we let you try freshly extracted oil. But we do not bottle it unfiltered. Because we want what you take home to still be extra virgin when you open it.
Frequently Asked Questions
What is unfiltered olive oil and why is it cloudy?
It is freshly extracted EVOO that has not undergone filtration. It retains microparticles of olive pulp, skin, and plant water, which gives it that cloudy appearance. It may seem more natural, but those particles ferment over time and degrade the oil. Cloudy appearance is not synonymous with quality.
Is unfiltered oil better than filtered?
No. When consumed very fresh, freshly milled, an unfiltered one can have interesting nuances. But after a few days or weeks, the suspended particles ferment and generate defects. A properly filtered oil preserves all its organoleptic and nutritional qualities for months. Filtering is protecting, not removing.
Why at Molino y Cata do you not sell unfiltered oil?
Because we cannot guarantee that it reaches the customer in optimal conditions. The unfiltered starts to degrade from the moment it leaves the olive mill. In an olive oil shop where the oil can be on the shelf for weeks before being sold, selling unfiltered would be compromising the quality. We prefer honesty over marketing.
Is unfiltered oil cheaper to produce?
Yes. Filtering costs money: cellulose plates, labor, time, and a 3-5% loss of the product. Selling unfiltered is, in many cases, a cost-saving measure disguised as a premium product. Marketing sells it as more artisanal and natural, but the economic reality is that it is cheaper not to filter.
When does it make sense to try an unfiltered oil?
Only freshly milled, directly at the olive mill or in the first days after extraction. If you visit an olive mill during the campaign and they offer you to try it from the tank, do it: it is a unique experience. But do not buy a bottle to keep at home for weeks. For domestic use, always filtered.