Overview
EN ISO 7973:2015 (ISO 7973:1992 adopted by CEN) specifies a standardized amylograph method for the determination of the viscosity of flour. The procedure measures the gelatinization behavior of starch in a flour–water suspension by heating it at a controlled rate and recording viscosity changes with an amylograph. The method applies to wheat and rye flour and to wheat and rye grain (after milling).
Key topics and technical requirements
- Principle: prepare a suspension of flour in water, heat from 30 °C while stirring and record viscosity until the curve reaches a maximum and begins to fall (approx. 95 °C).
- Instrument: Brabender-type amylograph with specific configuration (heating coils around bowl; torque measurement head changeable).
- Operating settings:
- spindle speed: 75 ± 1 rev/min
- temperature rise: 1.50 ± 0.03 °C/min
- recorder linear speed: 0.50 ± 0.01 cm/min
- Sample preparation:
- determine sample moisture (ISO 712 referenced) and adjust test portion mass according to moisture content (table in the standard).
- final suspension mass in bowl: approx. 530.0 g ± 0.5 g (example: 90 g flour + 450 g water for grain-derived meal).
- Results and calculation:
- maximum viscosity reported as amylograph units (AU), to the nearest 5 AU.
- temperature at maximum viscosity is calculated from recorder distances and reported to 0.5 °C.
- if viscosity exceeds instrument range (> 1 000 AU), a supplementary weight or smaller test portion is used to extend range.
- Calibration and references: Annex A addresses amylograph calibration. Normative references include ISO 712 (moisture) and ISO 3093 (milling for grain samples).
Practical applications and users
- Quality control in milling and baking: predict dough behavior and processability by assessing starch gelatinization and residual alpha‑amylase activity.
- Flour and grain laboratories: routine testing for specification compliance and batch comparisons.
- Millers, bakers and food processors: formulation and process adjustments based on flour viscosity properties.
- Research and breeding programs: study functional properties of wheat and rye varieties.
- Grain trade and specification: provide reproducible viscosity data for contractual and quality purposes.
Related standards and keywords
- Related ISO standards: ISO 712 (moisture determination), ISO 3093 (milling for grains).
- SEO keywords: EN ISO 7973:2015, ISO 7973 amylograph, flour viscosity test, cereal standards, wheat flour viscosity, rye flour viscosity, amylograph viscosity, flour testing, CEN standard.
This standard delivers a repeatable, instrument‑based method to evaluate starch gelatinization and viscosity in cereals - essential data for quality control, process optimization and research in the cereal and baking industries.
