1The Official Analytical Standards
The official classification of extra virgin olive oil in the European Union (under Regulation EEC 2568/91) is backed by international chemical protocols developed by the ISO (International Organization for Standardization).
Here is a detailed guide to the primary ISO methods used in certified laboratories:
2ISO 660 — Free Acidity (Titrimetric Method)
Free acidity measures the percentage of free fatty acids (expressed as grams of oleic acid per 100g). It is an indicator of olive health: healthy olives pressed immediately yield low acidity. * The Principle: An acid-base neutralization titration using potassium hydroxide (KOH) and phenolphthalein. * Legal Limit for EVOO: ≤ 0.8% (high-quality oils consistently score below 0.2%).
3ISO 3960 — Peroxide Value (Iodometric Method)
This method quantifies hydroperoxides, which represent the primary products of lipid oxidation. * The Principle: Reactive peroxides oxidize potassium iodide (KI) to free iodine (I₂), which is then titrated with sodium thiosulfate (Na₂S₂O₃) using starch as an indicator. * Legal Limit for EVOO: ≤ 20 mEq O₂/kg (fresh artisanal oils typically score below 8).
4ISO 12228 / ISO 27107 — Sterol Profile (GC-FID)
Every vegetable species has a unique "sterol fingerprint." This gas chromatographic test is the ultimate check against fraud. * The Principle: Saponification of the oil, extraction of the unsaponifiable fraction, thin-layer chromatography, silylation of sterols, and gas chromatography. * Markers: A campesterol value > 4.0% indicates contamination with canola oil, while delta-7-stigmastenol > 0.5% reveals adulteration with sunflower oil.
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We analyze every lot of our Tuscan Extra Virgin Olive Oil in compliance with the highest ISO standards.
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