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Stored canola with moisture content higher than 8% will be at higher risk of spoilage as temperatures warm up this spring. Farmers with high-moisture canola will need a plan to protect that canola – and turning on the fans without adding heat to the air might not be the best approach. This time of year, most days are poor drying days. When air is not warm enough to actually do any drying, then you’re just warming up the bulk enough to give a head start to the microbial processes that lead to spoilage. Read the full article. The Canola Encyclopedia also has a section on the limitations of natural air drying.
Reader question on storage of high-green canola
The question: “I have canola set to go out April and July. Some is in 36-foot 7-ring bins (25,000 bushel), some is in 10,000-bu and 5,000-bu hoppers. All bins have air. Grain is dried to 7.5% to 9% moisture, so I’m not concerned about that, but I have green counts anywhere from 2% to 22%. How would you recommend storing it? Canola is cold now, but I have options to move it around to hoppers or flat-bottom bins. Since my bins will get hot in the summer and create sweating on outsides of the bin, there could be a big difference in temperature from the outside edge (40°C) to the inside of the bin (-10°C).
The response (from CCC agronomy specialist Angela Brackenreed): Unfortunately, there is no literature available on large scale storage of green seed, but we of course know from smaller scale work that green seeds are typically higher moisture are more biologically active, therefore creating more volatility within the bulk. However, after time, respiration of these green seeds will diminish, and they can be stabilized at cold temperatures.
Based on observation from storage researchers at the University of Manitoba, they recommend assuming for every point of green seed, the “safe storage time” be reduced by approximately 5%.
If there were no green seed in the bulk’s you’ve described, it could be cautiously assumed that your bulk should be stable for well over 20 weeks, likely upwards of 40+ weeks. The higher green count bulks would be considered very unstable, particularly right after harvest, but the lowest counts could be managed for approximately 18 to 38 weeks. I realize this is a massive range, but it will be so dependent on things like distribution of green seed throughout the bin (ex. pockets or evenly mixed), degree of immaturity of the seed, as well as other conditions of the canola like any mold growth, degree of dockage/ fines, etc.
Larger bin storage can certainly be more risky with much greater insulative capacity if temperatures do start to rise. Splitting up loads into smaller quantities could certainly be helpful, particularly if it means you’re allowing more ventilation room inside the bin.
Even with high temperature differentials from the outside of the bin to the inside central core, the bins monitored during summer storage showed more stable conditions when they were not warmed up or turned. These bins had no green seed, so we cannot assume your situation to be the same. With limited moisture to actually migrate in your situation, the risk should be lower with regards to temperature differentials in the bin.
I’d be most cautious with the highest moisture and highest green count bins- turning and reducing the overall volume per bin. If there is no instability in the bin, turning may not actually promote longer safe storage days, but it is still the best way to break up any hot spot formations (that can easily go undetected by cables). I would not recommend warming the grain up.