Overview
ISO 6571:2008 specifies a standard hydrodistillation method for determining the volatile oil (essential oil) content of spices, condiments and culinary herbs. The method reports volatile oil as millilitres per 100 g of dry product and is intended for routine laboratory analysis, quality control and specification testing across the spice and herb supply chain.
Key topics and technical requirements
- Scope: Covers determination of all substances entrained by steam under the standardised test conditions (volatile oil content expressed as ml/100 g dry product).
- Principle: A suspension of the sample is steam-distilled; the distillate is collected into a graduated tube containing a measured volume of xylene which fixes the volatile oil. After phase separation the total organic volume is read and the xylene volume deducted; results are corrected to dry-matter using moisture determined by ISO 939.
- Reagents & cleaning: Requires analytical-grade reagents (notably xylene) and specified cleaning solutions (acetone; detergent or acid/dichromate mix with safety warning).
- Apparatus: Specifies a robust glass distillation assembly (round-bottom flask, condenser system with graduated tube, steam trap), anti-bumping granules, heating device with temperature control, pipette and analytical balance.
- Procedure: Includes apparatus preparation, sample grinding (per ISO 2825), specified test portions and distilled volumes/times. Annex A lists test parameters (mass, water volume, distillation time) for common spices (e.g., clove, oregano, black pepper).
- Expression of results: Calculation uses measured xylene volume, total organic phase volume and moisture content to yield ml volatile oil per 100 g dry product.
- Precision: Annex B summarizes interlaboratory precision (repeatability and reproducibility). Example reproducibility limits: oregano ~0.536 ml/100 g, cloves ~3.662 ml/100 g, black pepper ~0.796 ml/100 g.
Applications and who uses it
- Food testing laboratories for specification testing and batch release.
- Spice processors and manufacturers for quality control and product specification.
- Exporters / importers to verify declared essential oil content for trade compliance.
- Regulatory agencies and standard bodies for surveillance and enforcement.
- R&D and formulation teams assessing aroma profile, extraction efficiency or raw-material quality.
This method is suitable wherever accurate quantification of volatile oils in culinary herbs, spices and condiments is required for product quality, labeling, or research.
Related standards
- ISO 939 - Determination of moisture content (entrainment method) - used for dry-weight correction.
- ISO 2825 - Preparation of a ground sample for analysis.
- ISO 948 - Sampling of spices and condiments.
- ISO 5725-1 / -2 - Accuracy, repeatability and reproducibility (referenced in Annex B).
Keywords: ISO 6571:2008, volatile oil content, hydrodistillation method, spices, condiments, herbs, essential oil analysis, quality control, analytical method.
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