Overview - EN ISO 6571:2009 (ISO 6571:2008)
EN ISO 6571:2009 specifies a standardized hydrodistillation method for the determination of volatile oil content in spices, condiments and culinary herbs. The method describes sample preparation, required apparatus and reagents (including xylene), the distillation and collection procedure, calculation of volatile oil expressed as millilitres per 100 g of dry product, and reporting requirements. This European adoption of ISO 6571:2008 is intended for laboratories performing quality control, regulatory testing and product specification for spice and herb raw materials and finished blends.
Key topics and technical requirements
- Principle: Steam (hydro) distillation of an aqueous suspension; volatile oil is fixed into a measured volume of xylene and the organic phase volume is read after separation.
- Apparatus: Robust glass distillation assembly with graduated collection tube, condenser, side-arm with stopper, steam trap and anti-bumping granules. Apparatus details and dimensions are specified.
- Reagents: Analytical-grade water and xylene (fixing solvent). Cleaning solutions such as acetone or detergent/acid dichromate mix are specified with safety warnings.
- Sample preparation: Grounding and mesh sizes referenced to ISO 2825; specified test portions and precautions to avoid overheating during crushing.
- Test parameters: Normative Annex A lists mass of test portion, water volume and distillation time for many spices (examples: aniseed 25 g / 500 ml / 4 h; cloves 4 g / 400 ml / 4 h; oregano 40 g / 600 ml / 4 h).
- Calculation: Volatile oil (mL/100 g dry product) = measured organic phase minus xylene, corrected for test portion mass and moisture content (moisture by ISO 939).
- Performance data: Precision from interlaboratory trials is included. Example repeatability/reproducibility limits:
- Oregano (≈1.907 mL/100 g): r = 0.176, R = 0.536
- Cloves (≈13.956 mL/100 g): r = 1.960, R = 3.662
- Black pepper (≈2.624 mL/100 g): r = 0.331, R = 0.796
- Reporting: Requires identification, method reference, distillation time, results, moisture content, and notes on deviations or incidents.
Applications - who uses it and why
- Quality control laboratories in spice processors, food ingredient suppliers and flavor houses to verify volatile oil specifications.
- Regulatory and conformity bodies for product labelling, import/export checks and consumer safety.
- R&D and formulation teams assessing oil-bearing herbs for flavor, aroma intensity and extraction studies.
- Contract testing laboratories providing certified analyses for supply chain assurance.
Benefits include consistent, comparable volatile oil results for specification, batch release, and sensory correlation.
Related standards
- ISO 2825 - Preparation of a ground sample for analysis (sample grinding/mesh).
- ISO 939 - Determination of moisture content (entrainment method), used to report results on a dry-matter basis.
Keywords: EN ISO 6571:2009, ISO 6571:2008, volatile oil content, hydrodistillation method, spices and condiments, herbs, xylene, distillation, spice analysis.
