Wheat - Chapter 4 | Official Grain Grading Guide

Determination of commercially clean

Dockage is not assessed on wheat samples that meet the commercially clean specifications defined in the wheat commercially clean determinant table. All samples must be analyzed to determine if they meet commercial cleanliness standards prior to dockage assessment. The analysis of samples which are clearly not commercially clean may consist of a visual assessment. For example, if there is no doubt that a sample contains more than 0.05% of small seeds without hand sieving and weighing the seeds then dockage will be assessed using procedures defined under Determination of dockage. Where there is any doubt regarding whether the sample is commercially clean, the sample must be analyzed using the procedures outlined below in steps 1 through 14 to confirm that the sample is not commercially clean prior to assessing dockage.

  1. Using a Boerner-type divider, divide the sample to obtain a representative portion.
    • Official samples shall be at least 1 kg.
    • Unofficial samples shall be at least 1 kg.
  2. Place approximately 250 grams of the sample at a time on the No. 5 buckwheat sieve nested over the No. 4.5 round-hole sieve.
  3. Move the sieves from left to right 30 times using a sifting motion. One complete motion is approximately 10 cm from the center to one side, back to the center, approximately 10 cm to the other side and back to the center.
  4. All broken wheat passing through the No. 5 buckwheat hand sieve or the No. 4.5 round hole hand sieve is weighed and the percentage calculated to determine if it meets the commercially clean specification of the grade for broken through a No. 5 buckwheat sieve. (Column #1 in the wheat commercially clean determinant table)
  5. Small seeds passing through the No. 4.5 round hole sieve are weighed and the percentage calculated to determine if they meet the commercially clean specification of the grade for small seeds. (Column #2 in the wheat commercially clean determinant table)
  6. Material other than broken grain and small seeds passing through the 4.5 round hole sieve is weighed and the percentage calculated to determine if it meets the commercially clean specification of the grade for attrition. (Column #3 in the wheat commercially clean determinant table)
  7. The sample portions remaining on top of the No. 5 buckwheat sieve and the 4.5 round hole sieve are recombined and divided using a Boerner-type divider to a representative portion of not less than 250 grams.
  8. The portion divided from step 7 is handpicked to remove large seeds (as defined in the Glossary), roughage and wild oats.
  9. The roughage material is weighed and the percentage calculated to determine if it meets the commercially clean specification of the grade for roughage. (Column #4 in the wheat commercially clean determinant table)
    • Note: If the roughage material contains unthreshed wheat heads, the heads are squeezed to remove the kernels of wheat prior to weighing. The wheat kernel is not included when assessing the concentration of roughage for commercial cleanliness. However, care should be taken to keep these wheat kernels separate. If it is determined that the sample is “NCC”, kernels squeezed from the unthreshed heads will be included in the dockage.
  10. The percentages of small seeds, attrition and roughage are added together to determine if the total meets the commercially clean specification of the grade for total small seeds, attrition and roughage. (Column #5 in the wheat commercially clean determinant table)
  11. The large seeds are weighed and the percentage calculated to determine if they meet the commercially clean specification of the grade for large seeds. (Column #6 in the wheat commercially clean determinant table)
  12. The wild oats are weighed and the percentage concentration calculated to determine if they meet the commercially clean specification of the grade for wild oats. (Column #7 in the wheat commercially clean determinant table)
  13. The percentages of small seeds, large seeds, and wild oats are added together to determine if the total meets the commercially clean specification of the grade for total small seeds, large seeds and wild oats. (Column #8 in the wheat commercially clean determinant table)
  14. The percentages of small seeds, large seeds, wild oats, roughage and broken grain through the No. 5 buckwheat sieve are added together to determine if the total meets the commercially clean specification of the grade (Column #9 in the wheat commercially clean determinant table)

Should the percentage concentration of any of the factors determined in steps 1 through 14 exceed the specifications set out in columns #1 through #9 of the wheat commercially clean determinant tables the sample will be considered to be not commercial clean.

Dockage will be assessed on samples determined to be not commercially clean using the procedures defined in Determination of dockage with the following exception. The exception relates to those samples which are determined, by hand sieving, to be NCC because of the concentration of attritional material either alone (Column #3 in the wheat commercially clean determinant table) or as a component of Total Small Seeds, Attrition and Roughage (Column #5 in the wheat commercially clean determinant table).

The attritional material from these samples will not be reconstituted back into the sample but will be added to the dockage removed by the Carter dockage tester. This procedure will ensure that attritional material that causes a sample to be designated NCC is not expelled by the fan of the Carter dockage tester and is retained in the sample in the event of a reinspection request.

Note:

Large seeds, small seeds, roughage and attrition are defined in the Glossary.

Export ready (ER)

Export ready refers to carlots which meet the following criteria:

  1. The lot must meet the commercially clean specifications for the grade
  2. Wheat of other classes and contrasting classes must meet the export specifications for the grade
  3. Total foreign material must meet the export specification for the grade.

Not ready for export (NRE)

Not export ready refers to carlots which are commercially clean but do not meet the export specifications for either wheats of other classes, contrasting classes or foreign material