Overview
EN ISO 520:2010 (Cereals and pulses - Determination of the mass of 1000 grains) specifies a standardized laboratory method to determine the mass of 1 000 grains for cereals and pulses (except seed lots for sowing). The procedure produces results expressed either as received or on a dry matter basis and is intended for routine quality control, trade inspection and research where consistent, comparable grain-size data are required.
Key topics and technical requirements
- Scope: Applicable to all cereal and pulse species except seed lots for sowing purposes.
- Principle: Select a test portion, separate whole grains, weigh the whole grains and count them; calculate the mass of 1 000 grains by proportion.
- Sampling and test portion: A test portion equivalent to about 500 grains is recommended; for straw cereals a mass of ~30 g commonly meets this instruction. Tests are carried out in duplicate.
- Apparatus:
- Sample divider (if needed)
- Grain counter (photoelectric counter recommended) or manual counting
- Balance capable of reading to 0.001 g (weighing reported to nearest 0.01 g in procedure)
- Moisture correction: To report results on a dry matter basis, determine moisture content using ISO 712 (cereals) or ISO 24557 (pulses), then correct m1 using the specified formula.
- Expression of results: Rules for decimal places depend on mass range (e.g., two decimals if <10 g; one decimal for 10–100 g; whole number if >100 g).
- Precision and uncertainty:
- Repeatability limit r ≈ 1.3 g
- Reproducibility limit R ≈ 2.3 g
(These figures apply to masses on the dry matter basis in the range ~29.8 g to 48.2 g.)
- Expanded uncertainty for that range: U ≈ ±1.6 g.
- Special cases: Separate decorticated and non‑decorticated grains; count twin oat grains as two.
Applications and users
EN ISO 520:2010 is used for:
- Grain quality laboratories and commercial testing for grading and specification compliance
- Trade and inspection bodies requiring standardized mass of 1000 grains data for contracts and tariffs
- Milling and food processing companies for process control and yield estimation
- Research institutions conducting comparative studies on varietal grain size (note: not for seed‑sowing lots)
Keywords: mass of 1000 grains, ISO 520:2010, cereals and pulses, determination of the mass of 1000 grains, moisture correction, repeatability, reproducibility, grain quality.
Related standards
- ISO 712 - Cereals and cereal products - Determination of moisture content (reference method)
- ISO 24557 - Pulses - Determination of moisture content - Air‑oven method
- ISO 5725 series - Accuracy (trueness and precision) of measurement methods (used for interlaboratory precision analysis)
This standard ensures consistent, repeatable measurement of grain size for quality control, trade and research across laboratories.