Grades are assigned based on a sample’s ability to meet tolerances for various grading factors. A grading factor is a physical condition or feature that is evaluated to determine the quality of the grain. This condition can be a result of growing conditions, handling procedures or storage practices.
All grain grade standards and tolerances are listed by crop in the Official Grade Grading Guide.
The Grain Research Laboratory has extensively studied the impact of grading factors on the overall quality of grain. We used this research to establish acceptable tolerances for various grading factors to ensure the safety and end-use qualities of grain. We work to make sure grain grades are evaluated using effective, precise and user-friendly tools. New technology considered for use in grain grading must be
- able to work as well in an elevator environment as it does in a laboratory
- must be time sensitive
Objective grading factors
Objective grading factors have numerical tolerances or minimums and maximums per grade.
A maximum of 0.1% severely sprouted, by weight, in a sample of Wheat, No. 1 Canada Western Red Spring (CWRS)
Sprout damage is an objective grading factor in wheat. To evaluate sprout damage in a sample, inspectors divide out a sub-sample, separate out kernels from the sub-sample showing any evidence of sprouting. They may use a 10-power magnifying lens to confirm sprouting activity. The inspector will weigh the sprouted kernels and record the total as a percentage of the weight of the entire sample. In a 1 kg sample of Wheat, No. 1 Canada Western Red Spring, the maximum tolerance of severely sprouted of 0.1% is equal to 1 gram.
Visual grading factors
For visual grading factors, there are no percentages set as tolerances for each grade. Samples affected by a visual grading factor are graded using the Degree of Soundness (definition of the grade) and standard samples or prints prepared by the Canadian Grain Commission. The standards demonstrate the physical interpretation of the Degree of Soundness defined in the Canada Grain Regulations.
Example: Degree of Soundness
The Degree of Soundness for a Wheat, No. 1 Canada Western Red Spring reads: Reasonably well matured; reasonably free from damaged kernels.
Inspectors compare samples to this definition and to the standards that represent, as close as possible, the minimum level of quality expected for a particular grade. The sample in review must be better than or equal these resources; otherwise, it is assigned to the next lower grade.
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