It can seem nice and warm outside, but it can still be cold inside a grain bin.
That means farmers have to be careful now if they’re trying to dry last fall’s damp grain that sat all winter. Adding heated air before all the grain is above the freezing point could create more problems than it fixes.
“Warm the grain first,” said Digvir Jayas, an internationally acknowledged grain storage expert and the vice-president for research at the University of Manitoba.
“If you try to force too much (heated) air too quickly you can force… moisture to, rather than leaving the grain, to condense at the top.”
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Cooler air won’t absorb much moisture, so it can travel through the grain and out the top, avoiding the risk of condensation.
A cap of frozen grain at the top of the bin can freeze moisture rising from the lower parts, creating a risk for spoilage.
Instead of immediately heating binned grain, farmers should run air at a low rate, allowing the temperature inside to gradually rise and equalize. That can be achieved in about 24 hours, which can be broken into different sessions if the overnight temperature is falling beneath 10-12 C.
Different bins can experience different conditions, Jayas said. Big bins might not have that frozen grain at the top because a warm core of grain might have lasted through winter.
Many farmers are now drying grain as they deal with a damp crop left by last fall’s appalling harvest weather. Farmers who couldn’t dry grain in the fall often cooled the grain to protect it from heating during the winter.
Now that the weather has risen well above freezing most days, they’re trying to finally get it dry.
That’s where Jayas’ warning comes from: even after weeks of warm weather outside, the temperature of the grain can still be below freezing and no farmer wants to cause crop downgrading by being too hasty when trying to dry it.
Farmers deserve independent testing of bin aeration fans, says Jayas.
Farmers now rely on information provided by manufacturers and that creates risks.
“Farmers should be setting up an independent testing ability,” he said.
“For any new fan, farmers should say ‘We need an independent comparison of the curves.’”
When a farmer buys a bin fan, he receives the manufacturer’s data on its specifications, including graphs of how well it operates at certain rates and with certain amounts of resistance.
That data is not checked by third parties today, although a couple of decades ago it was.
Jayas said most manufacturers provide reliable data about their fans, but there’s always a chance that somebody hasn’t.
Inaccurate information could lead to a chronically malfunctioning system.
Jayas said farmers need to carefully manage their aeration systems even if they have good data and recommendations from manufacturers.
The way the system operates depends much upon how the fan interacts with the rest of the bin. What kind of a floor does it have? How big is the bin? How is the air vented out? All those factors can have major impacts on how the fan and aeration works in real-world conditions.
One factor many farmers can forget is the major impact upon fan performance that different grains can produce. For example, if a fan is installed in a bin so that it can supply enough power to dry and condition wheat, it might be inadequate to dry canola.
“They need to understand what their system is designed for,” said Jayas.
