Overview
ISO 6883:2017 specifies a laboratory method to determine the conventional mass per volume (litre weight in air) of animal and vegetable fats and oils. The standard defines how to convert between volume and mass for fats in the liquid state (excluding milk and milk‑derived fats). The value is expressed in kilograms per litre (numerically equal to grams per millilitre), and the method uses a calibrated pyknometer and controlled-temperature measurements to produce traceable results.
Key topics and requirements
- Scope and exclusions: Applies only to liquid animal and vegetable fats; milk and milk products are excluded.
- Principle: Determine the mass of a known volume of fat in a calibrated pyknometer at a specified temperature, then calculate the conventional mass per volume (litre weight).
- Apparatus:
- Water bath controllable to within ±0.1 °C and a calibrated thermometer (0.1 °C divisions).
- Jaulmes pyknometer (50 ml, side‑arm) with thermometer (preferred), or Gay‑Lussac (Type 3) pyknometer as an alternative.
- Precision balance capable of 0.1 mg resolution.
- Calibration:
- Calibrate pyknometer at least annually (or every 3 months for soda glass) using water; calibrate at 40 °C if glass expansion coefficient (γ) is known, otherwise at 20 °C and 60 °C to determine γ.
- Volume calculation uses V = (m2 − m1) / ρw, where m1/m2 are pyknometer masses and ρw is water’s litre weight at calibration temperature (table provided).
- Procedure and temperature control:
- Sample preparation per ISO 661 (do not filter or dry).
- Ensure fat is fully liquid at the test temperature (avoid crystal deposition).
- Immerse filled pyknometer in water bath until thermal equilibrium (about 2 h), record temperature to 0.1 °C, and weigh.
- Results and precision:
- Calculate pyknometer volume and then the conventional mass per volume of the fat.
- The standard includes precision data (repeatability and reproducibility) and reporting requirements.
Applications and users
ISO 6883:2017 is used where reliable conversion between mass and volume of fats is required:
- Food and oil testing laboratories performing compositional and trade analyses.
- Quality control in edible oil and fat processing (refineries, crushers, packers).
- Commodity traders and inspection bodies converting bulk volumes to mass for invoicing and transport.
- Regulatory agencies and standards organizations verifying declared densities/weights.
Key benefits: consistent, traceable litre weight/density data; reproducible volume↔mass conversions; temperature‑controlled methodology.
Related standards
- ISO 661 - Preparation of test sample (referenced for sample handling)
- ISO 5555 - Recommended sampling methods (sampling not part of ISO 6883)
- ISO 18301 - Oscillating U-tube method for determination of conventional mass per volume
Keywords: ISO 6883:2017, litre weight, conventional mass per volume, animal and vegetable fats and oils, pyknometer, Jaulmes pyknometer, Gay‑Lussac, calibration, water bath, density, laboratory method.
Open preview (PDF)Animal and vegetable fats and oils — Determination of conventional mass per volume (litre weight in air)