Official Grain Grading Guide

Mixed grain: Grading

Important definitions

Net weight of sample
The sample after cleaning and removal of dockage is referred to as the cleaned sample. Its weight is the net weight of the sample. For grading, percentages by weight refer to percentages of the net weight.
Hazardous substances in samples
Wear gloves and a mask to handle any samples that you suspect may contain hazardous substances. Hazardous substances are defined in section 1 of the Canada Grain Regulations as “any pesticide, desiccant or inoculant”.
Processed sample
An unofficial sample of grain declared to be conditioned or cleaned to meet end user specifications, and whereas, the determination of dockage and/or determination of commercially clean are not performed or reported.
Rounding rules
Rounding rules are outlined in schedule 3 of the Canada Grain Regulations. When official inspection results are expressed numerically, they should be expressed to the same decimal precision as the applicable tolerance in the primary and export grade determination tables.

Representative portion for grading

All grading is done on representative portions divided down from the clean sample, using a Boerner-type divider.

The optimum representative portion is the representative sample size within the minimum and maximum range used to obtain the most accurate result when assessing an objective factor. It is determined by taking into consideration the tolerance and concentration of the objective factor being assessed

Representative portion of mixed grain for grading (in grams)
Grading factorSample portion size range
MinimumMaximum
Broken25 g50 g
Ergot500 gworking sample
Excretaworking sampleworking sample
Fertilizer pelletsworking sampleworking sample
Fireburntworking sampleworking sample
Fusarium damage25 g100 g
Heated25 g100 g
Large seeds100 g250 g
Odourworking sampleworking sample
Sclerotinia sclerotiorum500 gworking sample
Soft earth pelletsworking sampleworking sample
Stonesworking sampleworking sample
Treated seedworking sampleworking sample

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2026-08-01