Warm harvest weather doesn’t mean grain spoilage issues disappear

Prairie farmers hoping for a dry, warm harvest will still need to pay close attention to grain condition when it comes off the field.

Even dry grain can be prone to spoilage if harvest temperatures are too high and hot grain is not cooled down quickly after it has been binned.

“Minimizing the risk of spoilage during storage depends on both temperature and moisture,” says Joy Agnew, a grain storage expert and project manager with the Prairie Agricultural Machinery Institute (PAMI).

“Even if grain is dry, it needs to be cooled to 15 degrees (15C) or lower. That’s the magic number that the Canadian Grain Commission has posted for all grain types.”

With an early harvest anticipated in many parts of Western Canada, daytime temperatures during harvest could reach the high 20s or low 30s.

Grain temperatures could also exceed recommended levels, placing more emphasis on the need to aerate binned grain.

Producers should monitor the temperature of grain and should turn on fans as soon as possible after the grain is binned.

“It it’s coming off the field in the 30C range, which is pretty common when it’s a warm harvest, it needs air on it pretty much immediately,” Agnew says.

“The other thing to keep in mind when cooling grain from really warm to ambient temperatures, is that you may get some drying as well.”

“The act of cooling (warm or hot grain) also removes a little bit of moisture so you can be losing a half to one percent of moisture content just by cooling it 10 or 15 or 20 degrees.”

Bins that are equipped with temperature cables take the guess work out of monitoring grain temperatures.

For bins that don’t have cables or other types of monitors, grain temperatures should be tracked as its being binned.

Fill a five-gallon pail during each unload and place a thermometer in the pail immediately, before the sampled grain has a chance to cool.

Managing aeration for optimal effect also requires care and attention.

Ideally, fans should be turned on when the outside temperature is cooler than the temperature of stored grain, Agnew says

However, any aeration is usually better than none at all when it comes managing hot grain, regardless of outside air temperatures.

“If the grain is hot, then run the fans continuously,” Agnew says.

“But if the grain is sort of cool, then consider running the fans only at night. But … any air flow at all on the grain is a good thing.”

Spoilage can occur quickly in grain that is binned warm and is not being aerated.

Risk of spoilage increases if outside air temperatures drop quickly and stored grain begins to respire.

“Aerate as soon as you can because depending on the moisture content of the grain, you have a limited window of time — like eight to 20 days or something like that — before spoilage or insect activity starts,” she says.

“So do it as soon as you can.”

Agnew said growers who anticipate storing grain through winter and into the following summer should also consider aerating during the coldest part of the year to push grain temperatures below 15C.

“The colder it (the grain) is going into the spring months, the longer the average temperature of the bin will stay below that magic number of 15C.”

Depending on moisture content, aerating during the cold winter months can cause grain to freeze or set up in the bin, Agnew warned.

Frozen grain that exceeds the recommended moisture content will not flow properly and could be prone to spoilage when thawing occurs.

Contact brian.cross@producer.com

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