What Is Peroxide Value in Olive Oil?

Peroxide value measures how much early-stage oxidation has taken place in an olive oil. For extra virgin olive oil the legal limit is 20 milliequivalents of active oxygen per kilogram, and the lower the figure, the fresher and better looked-after the oil.

It is one of a handful of chemical tests that decide whether an oil can be sold as extra virgin, alongside free acidity, UV absorbance and a sensory panel. It is also one of the most useful numbers for judging how well an oil has been made and stored.

What does peroxide value measure?

When olive oil is exposed to oxygen, the fats slowly begin to react with it. The first products of that reaction are peroxides. Peroxide value, often shortened to PV, measures the quantity of these peroxides in the oil, expressed as milliequivalents of active oxygen per kilogram (meq O₂/kg).

Peroxides are primary oxidation products: they appear early, before the oil develops any obvious stale or rancid smell. That makes peroxide value a useful early-warning sign. An oil can still taste fine while its peroxide value is creeping up.

What is a good peroxide value for extra virgin olive oil?

The UK and EU limit for extra virgin olive oil is 20 meq O₂/kg. Anything above that cannot legally be sold as extra virgin, whatever it tastes like.

Within that limit, lower is better. Freshly made oil from sound fruit, processed quickly and stored well, typically shows a figure well below the limit. A reading close to 20 suggests the oil has met oxygen somewhere along the way, whether from damaged fruit, slow processing, poor storage or simply age.

What causes a high peroxide value?

• Damaged or overripe fruit. Bruised olives, or olives left waiting too long before milling, start oxidising before they reach the mill.
• Heat and air during processing. Long, warm malaxation (the mixing of the olive paste) increases exposure to oxygen.
• Poor storage. Light, warmth and half-empty containers all speed up oxidation.
• Time. Every olive oil oxidises gradually. Peroxide value tends to rise as an oil ages, especially once opened.

Natural antioxidants in the oil, including polyphenols, help slow this process, which is one reason high-polyphenol oils tend to hold their freshness well. We explain polyphenols in What Is High-Polyphenol Olive Oil?

How does peroxide value relate to acidity and K232?

These tests measure different things, and together they give a fuller picture:

• Free acidity shows how much the fats have broken down, mainly through fruit damage or delays before milling. Our guide to olive oil acidity covers it in detail.
• Peroxide value shows early oxidation.
• K232 and K270 are UV absorbance readings. K232 also reflects early oxidation, while K270 picks up later-stage oxidation products and can reveal refined oil.

An oil can have low acidity but a high peroxide value, for example if it was made from good fruit but then stored badly. That is why a credible lab report shows all of these figures, not just one.

How do you find an olive oil's peroxide value?

It is not usually printed on the bottle. You will normally find it on a lab analysis certificate, which good producers and suppliers share on request or publish online. Look for the laboratory's name, a report number, a date and the method used. A recent date matters, because peroxide value can change over time.

How ours compares

Our single-estate, Coratina-led extra virgin olive oil was analysed by Studio Analisi Chimiche e Ambientali, an ISO 9001-certified laboratory, in January 2026 (report 2026.019-2). The results:

• Peroxide value: 7.06 meq O₂/kg (limit 20)
• Free acidity: 0.36% (limit 0.8%)
• K232: 1.44 (limit 2.50)
• K270: 0.1254 (limit 0.22)
• Polyphenols: 687 mg/kg (Folin-Ciocalteu)

You can see the full report on our lab results page. The oil is cold pressed, unfiltered and bottled at source, and available in 500ml, 750ml and 3L bottles.

Quick answers

What is the peroxide value limit for extra virgin olive oil?
20 meq O₂/kg under UK and EU rules.

Is a lower peroxide value better?
Yes. A lower figure means less early oxidation and generally a fresher oil.

Can I lower the peroxide value of oil at home?
No, but you can slow its rise by keeping the bottle closed, cool and out of the light, and using it within a few months of opening.