In January 2026, Stiftung Warentest, Germany’s leading consumer testing body, examined 25 olive oils (issue 2/2026). The result: only four were rated “good”, eight failed with “poor” — and not a single one reached “very good”. In Stiftung Warentest’s own summary: “every third olive oil fails”.
A few months later, in May 2026, Öko-Test arrived at a similar picture: of 30 extra-virgin oils, only two earned the top mark and seven failed. Mineral-oil components were found in every single sample, traces of pesticides in almost all of them.
This is no coincidence and no isolated case. It comes down to the way most of the product is made.
Why oils fail
Oxidation. Oil that has travelled too long or been stored badly turns rancid — measurably so, long before you can clearly taste it.
Blending. Cheap oils from several countries, mixed and masked with aromas. The label still reads “extra vergine”.
Sensory defects. Fusty, musty, winey-vinegary — faults that stand out in the lab and on the palate, but not to the layperson on the shelf.
What makes a good oil
Three things guard against disappointment: a clear origin (one country, better still one region), a harvest year on the bottle and dark glass instead of clear glass.
And the taste itself: a fresh extra virgin scratches slightly in the throat and tastes bitter. What many take for a fault is the opposite — it is the olive’s sign of life.
If you want to look more closely, we’ve gathered the marks of an honest oil and the signs of adulterated product.