Transcript: Taking a representative sample
Video length: 3 minutes, 56 seconds
(Introduction: Canadian Grain Commission logo)
(Title: Taking a representative sample)
The grade, dockage and general quality of your grain can vary within a field, bin and from truckload to truckload.
(Montage: Showcases a wheat field, a primary elevator and a truck driving in)
Proper sampling procedures will help ensure your sample accurately represents your grain’s quality.
(Montage: Grain being poured into an open pit)
In this video, we will review best practices for two common methods of sampling: manual stream sampling and pneumatic truck probe sampling.
(Montage: Person taking a sample from a falling stream of grain using grain scoop and a pneumatic probe taking samples from a truck.)
(Title: Manual stream sampling)
(Montage: Trucks filled with grain lining up to be unloaded)
Manual stream sampling can be performed while loading or unloading a truckload of grain.
(Montage: Example of proper grain scoop and pail)
To collect your representative sample, you will need a grain scoop and a 20-litre pail. Your grain scoop should have a rigid handle and a sample collector with a capacity between 50 and 200 grams.
(Montage: Grain falling into an open pit)
When sampling grain over an open pit, grain auger or conveyer hopper, be careful to ensure a buildup of grain does not choke the pit or hopper and block the grain flow.
This can limit the grain’s ability to free fall and prevent you from accessing the entire flow of grain.
(Montage: Person using grain scoop to take multiple samples and emptying contents in a pail)
Start loading or unloading the grain truck and insert the scoop into the grain stream with the cup of the scoop facing down.
Rotate the scoop 180 degrees to fill it, pull the scoop out of the grain flow, and empty the scoop into your pail.
It is important to alternate between taking samples from the left, middle and right of the grain stream.
Continue to draw samples at regularly timed intervals until the truck is finished loading or unloading.
Using short, consistent intervals and taking many individual scoop samples will make the final composite sample more accurate.
(Montage: Truck driving up to the pneumatic truck probe)
(Title: Pneumatic truck probe sampling)
(Montage: Close up of pneumatic truck probe taking a sample from the truck)
Some grain elevators use pneumatic truck probes to build composite samples that represent a truckload of grain.
Compartment type and core type probes with controlled air pressures are the recommended probe types for use by the industry.
(Montage: Animation of how a compartment type probe operates)
A compartment type probe operates on the principle that only grain that flows via gravity into the first chamber compartments are taken as the sample.
(Montage: Animation of how a core type probe operates)
A core type probe operates on the principle that only grain that is forced into the inner chamber is taken as the sample.
(Montage: Inspector controlling the pneumatic truck probe while sample collection unit is filling up with grain)
When the probe reaches the maximum depth of the truck, a pneumatic recovery system transports the sample from the probe and delivers to a sample collection unit in the inspection office.
(Montage: Animation of where the samples should be taken from the truck)
A recommended minimum of 8 samples should be taken from a single truck. This includes: one sample in each corner, one near the wall at the middle of each side of the truck and two samples from the middle area of the truck.
For a partitioned truck or truck and trailer, a recommended minimum of 10 samples should be taken.
(Montage: Truck filled with grain sits beside a pneumatic truck probe)
Sampling to the maximum depth and following the recommended sampling patterns helps ensure the final composite sample will accurately represent the lot of grain.
(Montage: primary elevator)
Accurate grading starts with an accurate sample!
(Montage: Website appears on screen)
For more information about representative sampling on the farm and at the elevator, visit grainscanada.gc.ca/sampling
(Canadian Grain Commission logo)