Extra virgin or virgin: what is the difference?
2 min read · updated 11 Oct 2026
Two tests, not one
An olive oil grade is decided by two kinds of test: chemical tests such as acidity and peroxide value, and sensory assessment by a trained tasting panel. Neither alone is enough for the extra virgin grade.
What does the chemical test say?
Acidity shows how far the fat has broken down; a lower figure means sounder fruit and better processing. Iran's national standard 1446 sets the extra virgin limits at 0.8 % acidity and a peroxide value of 20 meq/kg.
What does the sensory test say?
In the official sensory classification, extra virgin oil must have a median of defects of zero and a fruity median above zero. Virgin oil may have a slight defect: a median of defects up to 2.5, and still fruity.
Four official defect groups are recognised: mould and dampness, anaerobic fermentation (fusty), vinegary, and oxidised rancidity. The first three come from fruit quality and the fourth from storage.
What to check on the label
The grade of each batch is set by that batch's test result. If a test sheet is available, check which batch and date it belongs to and whether it includes a sensory assessment.
Frequently asked
Is extra virgin better than virgin?
Extra virgin is the higher grade: it meets stricter chemical limits and must show no defect in the sensory assessment.
Sources
- Boskou D. (ed.) (2006). Olive Oil: Chemistry and Technology, 2nd ed. AOCS Press.
- Iranian National Standards Organization (INSO). National Standard 1446: Olive oil, specifications and test methods.
This article is general information and is not medical advice.
