Polyphenols·3 min read
How to Read a Polyphenol Number (250 vs 600 vs 900 mg/kg)
What the number actually measures
When an olive oil quotes a polyphenol figure, it's giving you a concentration: the total weight of polyphenols in a given weight of oil, written as milligrams per kilogram (mg/kg). Higher means more of the antioxidant compounds — hydroxytyrosol, oleocanthal and the rest — that make a fresh, early-harvest oil taste the way it does.
One thing to settle first: a bigger number is not automatically a "better" oil for every use. It's a measure of intensity, not a score out of ten. But it is the single most honest signal of how much real, fresh extra virgin you're getting — provided you know how to read it.
The benchmark: 250 mg/kg
There's a line worth remembering. Under EU rules, an olive oil may claim its polyphenols "contribute to the protection of blood lipids from oxidative stress" only if it contains at least 5 mg of hydroxytyrosol and its derivatives per 20 g of oil — about 250 mg/kg. Think of 250 as the floor for "high-polyphenol," not the ceiling.
250 vs 600 vs 900
- ~250 mg/kg — the benchmark. A genuine high-polyphenol oil starts around here. Plenty of supermarket "extra virgin" doesn't reach it.
- ~600 mg/kg — genuinely high: roughly 2.4× the benchmark. This is the band a peak early-harvest oil lives in. You'll taste it — more pepper, more green bitterness.
- ~900 mg/kg and up — exceptional, and almost always the result of a very early harvest and a polyphenol-rich variety like Picual. Intense enough that a little goes a long way.
The polyphenol scale
Past a point, the gains are about intensity on the palate rather than a linear "more is better." A 900 oil isn't there to drink by the spoon — it's there to transform a plate with a small pour.
How it's tested — and why the method matters
Here's where a lot of big numbers fall apart. Polyphenols can be measured different ways, and they don't all give the same answer.
- Reference lab methods — chromatography (HPLC) and the Folin-Ciocalteu assay — give conservative results that can be compared oil to oil.
- NMR and some rapid methods can report substantially higher figures that aren't directly comparable to reference methods — so a dramatic number measured by NMR can look better than it is.
HPLC vs NMR
HPLC
The standard
- Recognised by the IOC + EU regulators
- The method behind label claims
- Comparable between oils
NMR
Reads differently
- Can report higher figures
- Not the regulator standard for claims
- Hard to compare directly
Ask not just “how high?” but “measured how — and by whom?” Look for a result from an independent lab — and a brand that publishes the report.
So when you see a number, the useful question isn't just "how high?" but "measured how, and by whom?" Look for a result from an independent lab — with a date, a batch, and a published report. Anything else is hard to trust.
Why a number needs a date and a batch
Polyphenols fade after harvest — with time, light and heat. That means a polyphenol figure is only ever true for a specific batch at a specific moment. A number printed on a generic label, with no harvest date and no report behind it, is closer to marketing than measurement. If you want to make sense of where these compounds come from in the first place, start with what high-polyphenol olive oil actually is.
A number you can't verify is just a bigger number.
That's why every OLEA tin carries a batch code and a QR that opens the lab report for that exact pressing — the harvest week, the variety, the acidity and the polyphenol result. The number on the tin isn't a claim. It's a receipt.