What is a good acidity level for olive oil?

Extra virgin olive oil must measure 0.8% or less under both EU rules and the International Olive Council standard. Carefully made oils from healthy fruit pressed quickly usually measure between 0.1% and 0.3%. Treat anything under 0.5% as a good sign, then check the peroxide value, K270, harvest date and polyphenols, because acidity alone cannot show freshness.

Is lower acidity olive oil always better?

Among virgin oils, a lower figure usually means healthier fruit and a shorter wait before pressing. But it is not proof of quality on its own. Refined olive oil is legally capped at 0.30%, lower than many extra virgins, and an oil can go stale on the shelf while its acidity barely moves. Compare acidity only between extra virgin oils, alongside other values.

Does olive oil acidity affect taste?

No. Free fatty acids have no taste you can detect, so acidity is measured only in a laboratory. The bitterness and peppery sting of a fresh oil come from polyphenols such as oleocanthal, not from acidity. In fact, early-harvest oils with the lowest acidity are often the most bitter and pungent, because green fruit is rich in polyphenols.

Is olive oil acidic in the pH sense?

Not in the way the word suggests. pH describes water-based liquids, and olive oil contains almost no water, so the acidity on a label is not a pH value. It is the proportion of fatty acids that have broken free from their triglycerides, a chemical measure of how carefully the olives were handled before and during pressing.

Does olive oil acidity increase over time?

Slowly. In a 27-month storage study of four extra virgin oils kept in clear bottles under light, final acidity was still 0.29-0.45%, inside the extra virgin limit. Yet one oil had already lost its grade in the fifth month through sensory defects. Peroxide, K270 and taste reveal ageing long before acidity does, so use the harvest date as your guide.

Reading the label #7

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13 October 2026 · 3 min read

What Does Acidity Mean in Olive Oil? Why 0.8% Is Only the Start

Quick Answer

Acidity in olive oil is the percentage of free fatty acids, expressed as oleic acid. It is not a sour taste or a pH value. Extra virgin oil must stay at or below 0.8%, and careful early-harvest oils usually measure 0.1-0.3%. A low figure is necessary for quality, but on its own it proves surprisingly little.

Acidity in olive oil is the share of free fatty acids, given as grams of oleic acid per 100 g of oil. It has nothing to do with sourness or pH: you cannot taste it, and it is measured only by titration in a lab. Extra virgin oil must be at or below 0.8%; carefully made early-harvest oils usually sit between 0.1% and 0.3%. A low figure is a requirement for quality, but on its own it proves surprisingly little.

Where the number comes from

Oil in the olive is stored as triglycerides. When fruit is bruised, overripe, infested or left waiting, the fruit's own enzymes split fatty acids off, and acidity climbs. So the figure is a record of how the fruit was treated before it reached the press. Rotondi and colleagues (Foods, 2021) followed 228 batches from seven Italian mills: oils from olives milled within 24 hours averaged 0.30% acidity, those from olives stored seven days or more 0.56%. Phenols fell from 246 to 143.6 mg/kg over the same delay. The stored oil was still comfortably extra virgin on acidity — the number hid a 41% loss of phenols.

Why a low figure alone proves little

Refining lowers it. EU rules cap refined olive oil at 0.30% acidity, lower than many extra virgin oils. The figure only means something when comparing virgin oils with each other.
Some fraud leaves it untouched. Soft deodorization strips off-flavours from defective oils under mild conditions that avoid the usual refining markers, which is why the EU added a limit on fatty acid ethyl esters (≤35 mg/kg) to catch it (Palagano et al., Foods 2020).
It is the slowest storage clock. Lobo-Prieto and colleagues (Molecules, 2020) kept four extra virgin oils in clear PET under light for 27 months. Final acidity was still 0.29-0.45%, yet one oil lost its extra virgin grade to sensory defects in the fifth month, and K270 rose well before acidity did.

What to read next to it

Annex I of EU Regulation 2022/2104 sets the full extra virgin profile: acidity ≤0.80%, peroxide ≤20, K232 ≤2.50, K270 ≤0.22, ΔK ≤0.01, ethyl esters ≤35 mg/kg, and a tasting panel median of zero defects. Article 10(d) adds a labelling rule: a stated acidity must be the maximum expected by the best-before date, and it may only appear with peroxide, wax and UV values in the same size and visual field. A lone "acidity 0.2%" on an EU label falls short of that. Our guide to extra virgin olive oil explains the tasting panel side.

Our two lots, side by side

Both of our 2025 lots were pressed within four hours of picking. Lot 2025-EH-03, Memecik olives picked green in October, measured 0.28% acidity, peroxide 7.4 and 384 mg/kg polyphenols. Lot 2025-EH-05, picked a month riper in November, measured 0.42%, 8.9 and 287 mg/kg. Acidity moved by 0.14 points; polyphenols fell by a quarter. Both pass any acidity check easily — the difference you taste, including the peppery sting in the throat, lives in the other numbers. Every value is published in our lot register, and the October lot is the one bottled as Ultra Premium 500 ml. For the wider range, see our olive oil collection.

Frequently Asked Questions

What is a good acidity level for olive oil?: Extra virgin olive oil must measure 0.8% or less under both EU rules and the International Olive Council standard. Carefully made oils from healthy fruit pressed quickly usually measure between 0.1% and 0.3%. Treat anything under 0.5% as a good sign, then check the peroxide value, K270, harvest date and polyphenols, because acidity alone cannot show freshness.
Is lower acidity olive oil always better?: Among virgin oils, a lower figure usually means healthier fruit and a shorter wait before pressing. But it is not proof of quality on its own. Refined olive oil is legally capped at 0.30%, lower than many extra virgins, and an oil can go stale on the shelf while its acidity barely moves. Compare acidity only between extra virgin oils, alongside other values.
Does olive oil acidity affect taste?: No. Free fatty acids have no taste you can detect, so acidity is measured only in a laboratory. The bitterness and peppery sting of a fresh oil come from polyphenols such as oleocanthal, not from acidity. In fact, early-harvest oils with the lowest acidity are often the most bitter and pungent, because green fruit is rich in polyphenols.
Is olive oil acidic in the pH sense?: Not in the way the word suggests. pH describes water-based liquids, and olive oil contains almost no water, so the acidity on a label is not a pH value. It is the proportion of fatty acids that have broken free from their triglycerides, a chemical measure of how carefully the olives were handled before and during pressing.
Does olive oil acidity increase over time?: Slowly. In a 27-month storage study of four extra virgin oils kept in clear bottles under light, final acidity was still 0.29-0.45%, inside the extra virgin limit. Yet one oil had already lost its grade in the fifth month through sensory defects. Peroxide, K270 and taste reveal ageing long before acidity does, so use the harvest date as your guide.

Sources

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