Up to two million tonnes of canola worth about $460 million are sitting in bins across the Prairies, in danger of spoiling.
Even in the busy summer season, it is worthwhile to monitor that investment and take actions to protect it against overheating, says Jim Bessel, senior agronomist with the Canola Council of Canada.
He recently examined a canola sample that looked fine.
“But when you put it up to your nose, it had a burnt caramel smell and when we rolled it out in a strip, it was all ash. It blew my socks off,” he said.
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“It had basically cooked and was worth just nothing. And that is such a shame because the producer has gone through a lot of work and expense to get it to that point.”
Bessel said a canola seed’s small size means there is little room for air to circulate. Also, it compacts under its own weight in large bins.
Moisture and heat increase the respiration of the seed and microorganisms in the grain, boosting the temperature and leading to mould growth.
The cycle builds on itself and if unstopped, temperature can build to the point of oxidation, or burning without flame.
Above 50 C, oxidation increases the temperature rapidly. If left alone, spontaneous combustion could occur within a few days.
Many modern bins have built-in probes and automatic sensors that work well, he said.
“But just because there is a sensor in there or you probe in a certain area and things look fine doesn’t mean that there isn’t a hot spot in there somewhere and you could miss it.”
Aeration should be used to keep the bin temperature below 20 C. Even then, hot spots can develop.
As outdoor temperatures rise, moisture inside the bin can migrate. It tends to accumulate at the bottom centre of the bin in hot weather and can cause heating that damages seed viability and lowers oil and protein quality.
Bessel said it is cheap insurance to remove canola from the centre of a bin and move it to another bin to interrupt moisture migration.
The amount to move depends on the size of the bin.
“If you have a large bin and you take out only a couple of hundred bushels, that might not do much for you.”
