Canola and rapeseed – Chapter 10 | Official Grain Grading Guide

Determination of dockage

Definitions

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 manual.

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

  • Canola, Sample Canada Account Fireburnt
  • Canola, Sample Salvage
  • Canola, Sample Condemned

Normal cleaning procedures

Important:

Wear gloves and a mask to handle any sample which you suspect may contain hazardous substances.

1. Set up the Carter dockage tester as follows:
Feed control # 3
Air control # 5
Riddle No. 000
Top sieve Blank tray
Centre sieve None
Bottom sieve None
Sieve cleaner Off
2. You also need the following hand sieves:
Round-hole sieves Slotted sieves
No. 5 No. .028
No. 5.5 No. .032
No. 6 No. .035
No. 6.5 No. .038
No. 7 No. .040
No. 7.5  

3. 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.

4. For hand sieving use approximately 250 g per sieving

Important:

  • Select the appropriate sized sieves.
  • When you use a slotted 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, or about eight inches.
  1. Use the round-hole sieve that will allow reasonably sound canola to pass thru the sieve while removing large material.
  2. Use the slotted sieve that will reduce the admixture of conspicuous inseparable material to within the grade tolerance with a minimum loss of reasonably sound canola.

5. Combine the separated, cleaned 250-g portions.

6. Turn on the Carter dockage tester.

7. Run the entire working sample through the Carter dockage tester for aspiration only.

8. Using a Boerner-type divider, divide the sample to a portion of not less than 10 g.

9. Analyze the 10-g portion to determine the percentage by weight of conspicuous admixture and soft earth pellets.

10. Determine the dockage, using the list under Composition of dockage.

Composition of dockage

Dockage includes

  • Material that remains on top of the round-hole sieve
  • Material that passes through the slotted sieve
  • Material removed by aspiration
  • Material that passes over the No. 000 riddle
  • Conspicuous admixture, up to established grade tolerances, handpicked from the cleaned sample
    • In Canola, Rejected (grade) Account Stones, dockage includes Conspicuous admixture handpicked from the cleaned sample up to the tolerance for the grade of the sample.
    • In Sample grades, Conspicuous admixture is not included as dockage. When the weight of the Conspicuous admixture exceeds 2.0% of the net weight, the Conspicuous admixture becomes a second reason for the sample grade. This is recorded in Remarks.
  • Soft earth pellets handpicked from the cleaned sample
  • Material removed by Cleaning for grade improvement

Primary samples, commercially clean

Commercially clean primary samples, other than submitted samples, can have up to 0.5% for broken and reasonably sound canola or rapeseed deducted from the gross weight of the dockage. Primary samples are considered commercially clean when meeting the requirements set out in the table below after following Normal Cleaning Procedures.

Definition of commercial cleanliness, canola
Grade name Material other than canola
remaining on top of the round-hole sieve and over No. 000 riddle %
Total net dockage %
Roughage material
such as wild oats, seed pods, knuckles
Total
No. 1 Canada 0.3 0.5 2.5
No. 2 Canada 0.3 0.5 2.5
No. 3 Canada 0.3 0.5 2.5

Primary samples, not commercially clean

In not commercially clean primary samples, there is no allowance for broken and reasonably sound canola or rapeseed. All the material removed by the slotted sieve is assessed as dockage.

Cleaning for grade improvement

If the grade of a delivery 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.

  1. After the cleaning assessment has been completed, examine the material to be removed and select your equipment according to the material you want to remove. See the table Cleaning for grade improvement — Canola for the list of equipment.
  2. Sieve the sample by hand or pass it through the Carter dockage tester, depending on the material.
  3. Weigh the additional dockage and add it to the original dockage.

Important:

When you use a slotted 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, or about eight inches.

Cleaning for grade improvement - Canola
Material to be removed Equipment Effect oncomposition of dockage
Weed seeds, broken grain or like material Carter dockage tester with air setting at #7, or approved round-hole or slotted sieves. Weed seeds and other material removed including canola, are added to dockage. Not more than 5.0% of sound canola may be removed for each single grade improvement achieved.
Damaged seeds Carter dockage tester with air setting at #7, or approved sieves.
Note: The material originally removed by aspiration is to be reconstituted back into the sample prior to cleaning for improvement.
Damaged seeds and other material including canola are added to dockage. Not more than 5.0% of sound canola may be removed for each single grade improvement achieved.

Cleaning sample grade canola

For canola that qualifies only for Sample Canada, Account Admixture after cleaning for grade improvement, dockage is assessed using the No. .035 slotted sieve, the round-hole sieve appropriate for the admixture, and the Carter dockage tester with air control set at #5.

For canola that qualifies only for Sample Canada, Account Damaged after cleaning for grade improvement, dockage is assessed using the appropriate round-hole and slotted sieves and the Carter dockage tester with air control set at #5. Use the slotted sieve appropriate for removing material consisting mainly of weed seeds and small broken grain. Also consider the maximum tolerance for inseparable admixture for these samples.

Important:

Variations from the above settings require authority from the Chief Grain Inspector.

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.

Procedures

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

Example:

95.0% Canola, No. 1 CAN

4.0% Barley, No. 1 CW

1.0% dockage