ISO 1446:2001

Overview

ISO 1446:2001 - "Green coffee - Determination of water content - Basic reference method" is the international reference procedure for measuring the moisture (water content) of green (unroasted) coffee. The standard defines a gravimetric “loss in mass” method under controlled low‑pressure and temperature conditions to establish a baseline for validating and checking routine moisture determination methods used in coffee quality control, trading and research.

Key topics and technical requirements

• Principle: Determination of water content by loss in mass when ground coffee reaches equilibrium with an anhydrous atmosphere, avoiding interfering reactions.
• Test conditions:
  • Temperature: 48 °C ± 2 °C
  • Pressure: 2.0 kPa ± 0.7 kPa (approx. 10–20 mmHg)
  • Drying to constant mass (difference < 0.0005 g between weighings 48 h apart); typical total oven time 150–200 h.
• Sample and sample prep:
  • Laboratory sample mixing per ISO 4072 sampling.
  • Test portion: typically 3–4 g per determination.
  • Predrying required if preliminary moisture > 11%: predry until ~8–10% before grinding.
  • Grinding requirements: >90% of particles <1 mm; >50%