Green kernels in bin present moisture, spoilage threat

Even though large bins are equipped with temperature probes, growers should collect numerous samples regularly

Tough grain and harvested cereal crops that contain an unusually high number of green kernels have the potential to cause costly headaches for prairie growers this year.

However, proper monitoring and management during storage can help farmers safely bin cereal crops that come off in less-than-perfect condition.

Cereal crops got off to a bad start this year across much of Saskatchewan and Alberta.

Mitchell Japp, provincial cereal crops specialist with Saskatchewan Agriculture, said poor moisture conditions early in the season hampered germination and produced thin plant stands in some regions.

Significant rain in late July produced a second flush of late germinating plants that resulted in fields with multiple growth stages and uneven plant maturity.

“Green kernels are going to be common in areas that had uneven emergence this year,” Japp said.

Japp said it’s hard to determine how much of this year’s cereal grain crop will contain immature kernels. However, he said many growers are facing unique harvest and grain storage challenges.

John Ippolito, a regional crop specialist in Kindersley, Sask., said the presence of green or immature kernels in harvested grain doesn’t necessarily mean growers will encounter storage problems.

However, it does mean they should use extra care when monitoring, sampling and conditioning grain.

“With immature kernels, the assumption is that those kernels will give up some of their moisture in the bin to the drier kernels around them,” Ippolito said.

“They’ll lose some moisture and the (kernels) … adjacent to them will actually take on some of that moisture, so unless there’s huge amounts (of green) in the bin, it really is not detrimental to the safe storage of the grain.”

Ippolito said the key to managing cereals with immature kernels is to sample accurately, test for moisture, monitor binned grain closely and keep grain cool using aeration.

“Bins with immature grain are … the ones where we would encourage guys to do more monitoring, run aeration and … pay close attention to the relation between higher moisture content and grain temperatures.”

Ippolito encouraged growers to reduce the temperature of the entire binned grain mass at the earliest opportunity.

Ideally, aeration can be used during harvest to reduce the temperature of binned grain to 5 C or 10 C.

Testing for moisture can also be a challenge on uneven samples.

Green kernels can often contain 30 percent or more moisture, so it is critical that growers take accurate representative samples.

Moisture test results are likely to be skewed unless a true representative sample is taken, which could result in a costly mistake.

Anecdotal reports suggest that moisture testers are less accurate when green kernels are present in a sample, but Ippolito said he hasn’t seen research to support those claims.

Large bins that hold tens of thousands of bushels can also present unique challenges, he added.

Some of these large bins are equipped with built-in moisture and temperature probes, which allow growers to monitor grain conditions quickly and easily from outside the bin.

However, those that don’t should be probed manually.

Regardless of bin size, growers should always probe suspect grain frequently and thoroughly so that hot spots can be located and managed before spoilage occurs.

“With the volume of grain that is in those bins, the centre of the bin often doesn’t get monitored properly or doesn’t get cooled off at the same rate as the outside does.”

Daryl Beswitherick, manager of quality assurance standards at the Canadian Grain Commission, said growers should take extra care this year when sampling.

Ideally, every load should be sampled thoroughly as it is being binned. Growers should use a dedicated sampling device or sampling ladle when drawing grain.

A ladle with reasonable holding capacity should be used to collect numerous sub-samples at regular and consistent intervals during the unload.

Each sub-sample should then be transferred into a larger holding container, such as a five gallon pail.

The entire contents of the pail should be mixed thoroughly once the entire load has been binned.

This procedure should be repeated for every load that is binned.

Growers can also prepare a composite sample that represents the entire contents of the bin.

For more information on how to do this, visit or the grain commission website at

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