Dockage in Canola Page ContentWhen you deliver your canola to a primary elevator, you can ask to watch the dockage assessment process. Dockage directly impacts your bottom line, so being involved ensures the proper process is followed and the correct equipment is used. Canola Dockage Basics for Farmers (5:49) — what is dockage and how it affects the value of your delivery. 5 STEPS TO ASSESSING DOCKAGE 1. COLLECTING The operator takes a representative sample of canola from the truck and divides it into a smaller working sample using a Boerner Divider. The working sample is weighed before it is cleaned. 2. SIFTING The working sample is passed over two sieves – one with round holes and one with slots. When the sample is sifted over the round-hole sieve, the canola drops through the holes and the large dockage material stays on top. When the sample is sifted over the slotted sieve, the canola stays on top and the smaller dockage drops through to the pan. Choosing the correct sieve sizes is a key part of the dockage assessment process. When selecting sieves, the goal is to remove enough conspicuous admixture so that the grade tolerance can be met, while also minimizing the loss of reasonably sound canola. Conspicuous admixture is material that stays in the sample after cleaning and is easily distinguished from canola such as flaxseed, mustard, weed seeds… etc. Choosing sieve sizes that will produce this result requires care and attention by the person doing the assessment.Important Update: The Official Grain Grading Guide was revised on August 1, 2023, to provide important clarification of the dockage process. The Guide indicates the smallest slotted sieve (0.028) should be used first, and the larger sizes only to clean for grade improvement. Now, the 1.0% tolerance for conspicuous admixture must be exceeded to justify moving to a larger sieve. The change clarifies the dockage assessment process, eliminates a degree of subjectivity, and allows for clearer understanding by farmers. Pay close attention to what is considered dockage. A range of sieve sizes can be used and operators use their discretion in choosing the most appropriate. If you observe many sound, smaller seeds being included as dockage, request a smaller sieve be used to minimize the loss of sound canola. 3. ASPIRATING Once the sample has been sieved, more dockage is removed through aspiration using the Carter Day Dockage Tester. 4. ASSESSING The aspirated sample is then assessed for conspicuous admixture – the material that can’t be easily cleaned from canola because it’s roughly the same size and shape as the seed. A small portion is divided from the cleaned sample from which the conspicuous material is hand-picked out, weighed and a percentage calculated. 5. CALCULATING The dockage removed by sieving, aspiration and hand picking is weighed and compared to the pre-cleaning weight of the working sample. This ultimately determines the total percentage of dockage and the final net weight of the canola delivery.