Rye: Determination of dockage


Dockage is assessed and recorded to the nearest 0.1%.

Dockage is defined under the Canada Grain Act as “any material intermixed with a parcel of grain, other than kernels of grain of a standard of quality fixed by or under this Act for a grade of that grain, that must and can be separated from the parcel of grain before that grade can be assigned to the grain.” Dockage is removed by following the cleaning procedures described in this chapter.

The sample as it arrives is referred to as the uncleaned or dirty sample. Its weight is the gross weight of the sample. Dockage is assessed on the gross weight of the sample.

Dockage is assessed in two stages.

  1. Follow Normal cleaning procedures, using the Carter dockage tester.
  2. Follow procedures for Cleaning for grade improvement. This cleaning can be done at any time after the cleaning assessment has been completed.

Dockage not reported

Important: Dockage is not reported for samples grading

  • Rye, Sample CW/CE Account Fireburnt
  • Rye, Sample Salvage
  • Rye, Sample Condemned

Normal cleaning procedures

Important: Wear gloves and a mask to handle any samples that you suspect may contain hazardous substances.

  1. Set up the Carter dockage tester as follows:

    Specifications for the Carter dockage tester
    Feed control # 5
    Air control Minimum # 4
    Riddle Number 25 or number 1
    Top sieve Number 6 buckwheat
    Centre sieve Number 5 buckwheat
    Bottom sieve Number 5 buckwheat
    Sieve cleaner control Off
  2. Using a Boerner-type divider, divide the uncleaned sample to obtain a representative portion.
    • Official samples shall be at least 1 kg.
    • Unofficial samples shall be at least 1 kg.
  3. Turn on the Carter dockage tester.
  4. Pour the sample into the hopper.
  5. After the sample has passed through the machine, turn on the sieve cleaner control for 2 to 3 seconds to remove kernels lodged in the sieve.
  6. Turn off the dockage tester.
  7. Lightly snap the retainer rod of the aspiration pan to loosen material gathered on the air screen.
  8. Remove the aspiration pan.
  9. Handpick large whole kernels of rye from the portion passing over the riddle and return them to the cleaned sample.
  10. Determine dockage. Use the list under Composition of dockage.

Composition of dockage

Dockage includes:

  • Rye with long rootlets removed by the riddle
  • For samples of rye which are graded Rye Sample CW/CE Account Sprouted any rye with long rootlets that was removed by the riddle will be returned to the sample and not assessed as dockage (See Sprouted)
  • Material other than rye removed by the riddle
  • Material removed by aspiration
  • Material that passes through the bottom number 5 buckwheat Carter sieve
  • Soft earth pellets, up to a maximum of 10% of the gross weight of the sample, handpicked from the clean sample.
  • Material removed by Cleaning for grade improvement

Cleaning for grade improvement

If the grade of a sample can be improved by additional cleaning, perform the cleaning and add the additional material to dockage. Cleaning for grade improvement can be done at any time after the cleaning assessment has been completed, including on export.

Procedures are summarized in the table which follows.

  1. After the cleaning assessment has been completed, sieve the sample using the number 6 buckwheat hand sieve.

    Important: When you use a hand sieve, move the sieve from left to right 30 times, using a sifting motion. One time is one complete motion from the centre, to one side, to the other side, and back to the centre. The total distance from left to right is 20 cm, about 8 inches.

  2. Weigh the additional dockage and add it to the original dockage.
Cleaning for grade improvement, Rye
Material to be removed Equipment Effect on composition of dockage
Broken kernels Number 6 buckwheat hand sieve

If the weight of broken kernels is over the grade tolerance but is

  • less than 5% of the gross weight, add to dockage
  • 5% or more of the gross weight, broken kernels become a grading factor; return them to the cleaned sample. Refer to Broken kernels.

Optional analysis

Where a shipper requests special cleaning of a carlot of grain at a terminal elevator, and the elevator manager agrees, dockage material will be analyzed for the presence of grain. The percentage and grade of any grain contained in the dockage will be reported.


  1. Analyze the official sample.
  2. Record the following on inspection records:
    • The percentage by gross weight to the nearest 0.1% and the grade of rye.
    • The percentage by gross weight to the nearest 0.1% and the grade of grain separable from dockage.
    • The percentage of dockage.


    • 95.0% Rye, number 1 CW
    • 4.0% Domestic Mustard Seed, number 1 CAN Oriental
    • 1.0% dockage
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