Overview
ISO 712-2:2024 - "Cereals and cereal products - Determination of moisture content - Part 2: Automatic drying oven method" specifies an automatic reference method for measuring moisture content in a range of cereals and cereal products. It defines the principle, apparatus, sample preparation, drying and weighing procedure, calculation and precision criteria for laboratories using an automatic drying oven with integrated balance and software control.
Key topics and technical requirements
- Scope and applicability: Applies to wheat, rice (paddy, husked, milled), barley, millet (Panicum miliaceum), rye, oats, triticale and sorghum in grain, milled grain, semolina and flour. Not applicable to maize and pulses (see ISO 6540 and ISO 24557).
- Principle: Automatic drying and re‑weighing at a controlled air/shelf temperature of 130 °C to 133 °C until constant mass is reached. Continuous chamber airflow reduces drying time vs. conventional ovens.
- Apparatus:
- Automatic drying oven with integrated analytical balance (accuracy ±0.001 g) and software for automatic reweighing and moisture calculation.
- Grinding mill that does not absorb moisture, limits temperature rise during grinding (≤ 5 °C), and produces required particle size (see ISO 3310-1 for sieves).
- Non‑corrodible or glass dishes sized so mass per unit area ≤ 0.3 g/cm².
- Sample preparation:
- Some products used without grinding if particle-size criteria (Table 1) are met.
- Grind samples rapidly when required; products with moisture outside ~9–15% require preconditioning as per ISO 712-1.
- Procedure & quantities:
- Typical test portion: 10 g ± 1 g (depending on oven manufacturer).
- Drying time can be reduced to ~60 min ± 5 min depending on oven and material; drying to constant mass.
- Weighing and moisture computation are automated; results averaged from two determinations meeting repeatability criteria.
- Precision:
- Repeatability (r) and reproducibility (R) provided for moisture range 8–14%: r ≈ 0.07%, R ≈ 0.30% (absolute differences as specified).
Applications and users
ISO 712-2:2024 is intended for:
- Laboratory analysts in cereal testing and quality control.
- Grain trading and inspection bodies requiring traceable moisture determination.
- Food processors, flour mills, rice processors and cereal research laboratories needing a standardized, fast, and reproducible moisture reference method using automatic drying ovens.
Practical benefits include faster throughput, integrated data capture, and harmonized results for contractual and regulatory testing.
Related standards
- ISO 712-1 - Reference method and principles
- ISO 24333 - Recommended sampling for cereals
- ISO 6540 - Moisture determination in maize
- ISO 24557 - Moisture determination in pulses
- ISO 3310-1 - Test sieves (particle size references)
Keywords: ISO 712-2:2024, moisture content, cereals, automatic drying oven, laboratory method, repeatability, reproducibility, wheat, rice, barley, semolina.