ISO 662:2016

Overview

ISO 662:2016 specifies standardized laboratory methods for determining the moisture and volatile matter content of animal and vegetable fats and oils by drying. The standard defines two drying procedures: Method A (sand bath or hotplate), applicable to all fats and oils, and Method B (drying oven), intended for non‑drying fats and oils with an acid value < 4. Under no circumstances are lauric oils analysed by Method B. Milk and milk products (and fats derived from them) are excluded from this ISO.

Key search terms: ISO 662:2016, moisture and volatile matter, fats and oils testing, Method A, Method B, drying oven, sand bath, hotplate.

Key topics and technical requirements

• Principle: Loss in mass on heating at 103 °C ± 2 °C until moisture and volatile substances are removed.
• Methods:
  • Method A: Sand bath or electric hotplate; typical test portion ~20 g; stirring with thermometer; repeated heating cycles until mass change ≤ 2 mg between successive weighings.
  • Method B: Drying oven at 103 °C; test portion 5 g or 10 g depending on expected moisture; successive oven periods (1 h then 30 min) until mass change criterion met (≤ 2 mg or 4 mg based on sample mass). If mass increases on reheating (autoxidation), use the smallest mass recorded or prefer Method A.
• Apparatus: Analytical balance (0.001 g resolution), suitable dishes/vessels, thermometer, desiccator, sand bath/hotplate or drying oven.
• Precision: Repeatability and reproducibility metrics are provided (example for ~0.3% moisture: repeatability limit ≈ 0.03 g/100 g; reproducibility limit ≈ 0.15 g/100 g).
• Reporting: Results expressed as percentage by mass (reported to two decimal places); test report must identify sample, sampling method, method used (ISO 662), operating details, results and repeatability check.

Applications and users

• Applications: Quality control, specification testing and regulatory compliance for edible oils, industrial fats, seed oils, tallow, fish oils, and other animal/vegetable lipids where moisture/volatile content affects stability, shelf life, frying performance and product labeling.
• Who uses it: QC laboratories, food and oil processors, analytical chemists, standards bodies, contract testing labs, and regulatory agencies assessing oil quality and conformity.

Related standards

• ISO 661 - Preparation of test sample (referenced in ISO 662)
• ISO 5555 - Sampling of animal and vegetable fats and oils (recommended)
• ISO 5725 series - Precision of measurement methods (interlaboratory precision data)

ISO 662:2016 is essential for consistent, comparable moisture and volatile matter determinations across laboratories handling fats and oils.