Buckwheat: 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”.
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.
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.

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 buckwheat for grading (in grams)
Grading factor Sample portion size range
Minimum Maximum
Cereal grains 50 g 250 g
Damage 10 g 50 g
Dehulled 10 g 50 g
Ergot 500 g working sample
Excreta working sample working sample
Fertilizer pellets working sample working sample
Fireburnt working sample working sample
Immature 10 g 50 g
Matter other than cereal grains 50 g 250 g
Odour working sample working sample
Sclerotinia sclerotiorum 500 g working sample
Size 250 g 250 g
Soft earth pellets working sample working sample
Stones working sample working sample
Treated seed working sample working sample