Soybeans: 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 section of the guide.

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 not reported

Important: Dockage is not reported for samples graded as

  • Soybeans, Sample Canada (colour) Account Fireburnt
  • Soybeans, Sample Salvage
  • Soybeans, Sample Condemned

Normal cleaning procedures

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

Samples that are commercially clean do not go through the Carter dockage tester.

  1. Using a Boerner-type divider, divide the uncleaned sample to obtain a representative portion.
    • Official samples shall be at least 1kg.
    • Unofficial samples shall be at least 1kg.
  2. Sieve the samples over the number 8 round-hole hand sieve, using approximately 250 g at a time, to remove all readily removable material.
  3. Set up the Carter dockage tester as follows:
    Set up the Carter dockage tester as follows:
    Feed control # 10
    Air control # 7
    Riddle none
    Top sieve blank tray
    Centre sieve none
    Bottom sieve none
    Sieve cleaner control off
  4. Turn on the Carter dockage tester.
  5. Pour the sample into the hopper.
  6. After the sample has passed through the machine, turn off the machine.
  7. Lightly snap the retainer rod of the aspiration pan to loosen material gathered on the air screen.
  8. Determine dockage, using the list under Composition of dockage.

Composition of dockage

  • Material passing through the number 8 round-hole sieve
  • Up to 10% by weight of soft earth pellets handpicked from the sample
  • Stems, pods, hulls, loose soybean seed coats, and coarse vegetable matter removed through aspiration with the Carter dockage tester, or handpicked from the sample

Important: Return all pieces of soybeans or whole soybeans, sclerotinia, ergot, weed seeds or other grains removed by aspiration to the sample where they are assessed as grading factors.

Aspiration is used only as an aid to help speed up the removal of lightweight dockage material from the sample.

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 soybeans.
    • The percentage by gross weight to the nearest 0.1% and the grade of grain separable from dockage.
    • The percentage of dockage.


    • 95.0% Soybeans, number 1 CAN, Yellow
    • 4.0% Domestic Mustard Seed, number 1 CAN Oriental
    • 1.0% dockage
Date modified: