Olive Oil Acidity: What It Actually Means

In brief. The free acidity of olive oil measures the percentage of free fatty acids (expressed as oleic acid), a sign of the degradation of the olives before and during extraction. The official IOC/EU thresholds: ≤ 0.8% for extra virgin (EVOO), ≤ 2.0% for virgin, > 2.0% = lampante (not marketable as-is in the EU). This figure has nothing to do with a sour taste: it reflects freshness and the care given to the fruit.

Acidity is the first figure a B2B buyer looks at on a certificate of analysis. It is the best-known benchmark of olive oil quality — but also the most misunderstood. Here is what it actually measures and how to use it when buying.

What is olive oil acidity?

Free acidity corresponds to the percentage of free fatty acids present in the oil, conventionally expressed as grams of oleic acid per 100 g of oil. An oil with 0.3% acidity therefore contains 0.3 g of free oleic acid per 100 g. The lower this level, the better the fruit was handled.

These fatty acids are released when the triglycerides in the olive break down, under the effect of enzymes (lipases), fruit injuries, mould, prolonged storage of the olives, or overly hot extraction. Acidity is therefore an indicator of degradation, not a taste parameter.

Acidity cannot be tasted

Contrary to a common belief, a "low-acidity" oil is not less "acidic" on the palate. Free acidity is chemically invisible to the palate: it cannot be perceived. The sensations of pungency and bitterness come from polyphenols, not from free fatty acids.

An acidity figure printed on a consumer label ("acidity 0.3%") is therefore a marketing argument: it tells you about the freshness of the batch, never about its taste. Conversely, an oil can have very low acidity and a mediocre sensory profile if the panel detects defects.

Acidity thresholds by category (IOC/EU)

Here are the maximum free acidity thresholds set by the trade standard of the International Olive Council (IOC/T.15/NC) and European Union regulation. Reference data, to be verified against the texts in force.

Category	Max free acidity	Commercial status
Extra virgin (EVOO)	≤ 0.80%	Premium, direct sale
Virgin	≤ 2.0%	Direct sale
Ordinary virgin (IOC only)	≤ 3.3%	IOC yes, EU no
Lampante	> 2.0% (EU)	Not marketable → refining

Key point for EU export: the European Union does not recognise the "ordinary" category. Above 2.0% acidity, a virgin oil is classified as lampante and must be refined before any market placement. It is the EU category that prevails for an import into Europe.

Acidity alone is not enough to grade an oil

A common buying mistake: believing that low acidity alone guarantees an extra virgin. False. The official classification rests on several simultaneous criteria:

1. Free acidity (≤ 0.8% for EVOO).
2. Peroxide value (≤ 20 mEq O₂/kg) — primary oxidation.
3. UV absorbances: K232, K270, ΔK — oxidation and refining.
4. IOC sensory panel: median of defects (Md = 0) and fruitiness (Mf > 0) for EVOO, assessed by an accredited jury.

An oil can meet the acidity limit but fail on peroxide, the UV indices or the panel. To understand all these parameters at once, try our COA quality classifier, which cross-checks all the thresholds.

How to use acidity when buying in bulk

• Require the COA per batch. Acidity must come from an IOC-accredited laboratory, not a commercial declaration. (See our quality process.)
• Never negotiate "acidity alone". First set the full category (acidity + peroxide + UV + panel), then the price for a given category.
• Beware of "borderline" oils. An oil at 0.79% passes as EVOO on paper, but leaves little margin for drift during transport and storage. A clearly low acidity (0.2–0.4%) is a better guarantee of freshness.
• Link acidity to freshness. Acidity that climbs over the months signals a poorly stored or ageing oil.

Tunisian oils of the Chemlali variety (South/Sfax) and Chetoui (North) routinely reach acidities well below 0.8% when cold-extracted quickly after harvest.

FAQ — Olive oil acidity

What acidity should an extra virgin olive oil have?

An extra virgin olive oil must have a free acidity ≤ 0.8% (IOC/EU standard). This is a maximum threshold: the best cold-extracted oils often show 0.2 to 0.4%. Acidity alone, however, is not enough to grade an oil as EVOO.

Does acidity make the oil taste more sour?

No. Free acidity is a chemical parameter, imperceptible on the palate. It measures free fatty acids, a sign of fruit degradation. Pungency and bitterness come from polyphenols, not from acidity.

What is the difference between extra virgin, virgin and lampante?

Extra virgin has an acidity ≤ 0.8% and no sensory defect. Virgin tolerates up to 2.0% and slight defects. Above 2.0% (EU), the oil is lampante: not consumable as-is, it goes to refining.

How is olive oil acidity measured?

By laboratory titration: the free fatty acids are assayed and the result is expressed as a percentage of oleic acid. This analysis appears on the certificate of analysis (COA), which must come from an IOC-accredited laboratory to be valid for export.

Does very low acidity guarantee a good oil?

Not on its own. Low acidity indicates a healthy, fresh fruit, but the official classification also requires a peroxide ≤ 20, compliant UV indices and a validated sensory panel. An oil can have low acidity yet present other defects.

Does acidity increase over time?

Yes, slowly, if the oil is poorly stored (heat, light, oxygen). Acidity that rises from one batch to the next betrays poor storage. That is why you must analyse each batch and favour a fresh oil from the campaign.

What acidity should you target for a bulk import?

For extra virgin destined for the EU, require ≤ 0.8% with a safety margin (ideally ≤ 0.5% at departure) to absorb transport drift. Always combine acidity with the other COA parameters.

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Are you importing bulk olive oil? Request a quote: each batch is delivered with its full COA (acidity, peroxide, K232/K270, polyphenols) from an accredited laboratory. For all the technical vocabulary, see the glossary.