Beans: 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. Percentages by weight for grading 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.”
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 determinants table.
Non-registered varieties
Where grain of any kind is not a registered variety under the Seeds Act, no person shall, except with the permission of the Canadian Grain Commission, assign a statutory grade to that grain which is higher than the lowest grade established by regulation for that kind of grain. An order is issued annually to allow non-registered varieties of beans to be graded higher than the lowest statutory grade.

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 beans for grading, grams
Grading factor Sample portion size range
Minimum Maximum
Contrasting classes 250 working sample
Damage 100 500
Ergot 500 working sample
Excreta working sample working sample
Fertilizer pellets working sample working sample
Fireburnt working sample working sample
Foreign material 250 working sample
Heated, rotted, mouldy 250 working sample
Insect parts working sample working sample
Odour working sample working sample
Other classes of beans that blend 100 250
Sclerotinia sclerotiorum 500 working sample
Splits 100 working sample
Stones working sample working sample
Treated seed working sample working sample
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