Wheat: 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 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

For Wheat, Sample Canada Western/Canada Eastern/Canada Account Admixture, dockage is not reported for removable material similar in nature to the admixture.

Normal cleaning procedures

1. Set up the Carter dockage tester with the following specifications

   Feed control	#6
   Air control	Minimum #4 (increase according to the nature of the material)
   Riddle	NumberNo. 25
   Top sieve	NumberNo. 6 buckwheat
   Centre sieve	NumberNo. 5 buckwheat
   Bottom sieve	NumberNo. 5 buckwheat
   Sieve cleaner	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 whole sound threshed kernels of wheat from the portion passing over the riddle and return them to the cleaned sample.

Composition of dockage

Dockage includes:

• Wheat with long rootlets, unthreshed wheat heads, and material other than wheat removed by the numberNo. 25 riddle
• Material removed by numberNo. 5 buckwheat sieve in the lower position
• Material removed by aspiration
• 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.

The purpose of this cleaning is not to remove all foreign material, but rather to reduce the admixture of conspicuous separable material to within the grade tolerance.

1. After the cleaning assessment has been completed, examine the material to be removed and select your equipment according to that material. See the table, Cleaning for grade improvement for wheat, for the list of equipment.
2. Pass the sample through the Carter dockage tester, or sieve the sample by hand, depending on the material.

   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, or about 8 inches.

3. Weigh the additional dockage and add it to the original dockage

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.