grain handling

With a growing acreage of pulses, dry edible beans and food-grade soybeans, the gentle handling of those crops is a growing concern for the farmers who raise them and the businesses that handle them. This is different from the way grain handling has traditionally been viewed – get the job done as soon as possible and don’t give a lot of thought to how the grain or seeds are handled. However, this can prove to be a costly error.

“The commodity we started to look at as far as gentle handling was dry edible beans,” said Ken Hellevang, Extension ag engineer specializing in grain handling. “We did some research looking at handling beans and a lot of the things we found there would apply to other situations as well.

“Wheat has been pretty tolerant of whatever we did. Corn is a little more fragile, but still pretty durable. When we look at soybeans, though, that is more of a balancing act and for anything food-grade, we are wanting to drastically reduce the amount of breakage,” he added.

Moisture content

All grains become more fragile to handle at lower moisture contents, including cereals, Hellevang noted.

“It has always been a trade-off, even with corn, that when you look at multiple handlings of the crop, as the moisture decreases you get more breakage.”

For instance, he said once the moisture level of soybeans drops below 11 percent, the breakage increases significantly. Beans, such as pintos, can safely be stored over winter at a 16 percent moisture level, but if that storage period gets extended into the summer months, it’s necessary to bring that moisture level down to a 10 percent level.

“What I typically recommend is once temperatures in the spring warm to 40 degrees, which means around 55 degrees during the day and dropping down to freezing at night, we use the aeration fans to dry down the grain further,” he said. “Usually the relative humidity in May is fairly dry and just running the aeration fan is all that will be required.”

Those lower moisture levels require care in transporting the commodities.


Seed damage based on temperature was also studied in detail with dry edible beans, according to Hellevang. When the beans got below freezing, processors were reporting huge losses from increased damage to the beans.

“We found that when the temperature dropped from 75 degrees to 55 degrees, we saw an increase in the breakage potential – so the colder the grain is, the more likely we are going to have breakage,” he said. “The years when we are out there handling frozen grain, we are likely to see increased damage as opposed to if that crop was 50 or 60 degrees.

“Ideally, if we were planning to handle that grain, it might be better to warm the grain a little bit, bring it back to 40 or so degrees, rather than leaving it at 20 degrees to minimize the potential for breakage during handling,” he added.

Hellevang explained two different ways this could be accomplished. First is turning on the heat in the bin for a day or two to bring the temperature up, while the other is not cooling the grain so much to start with.

“We used to recommend bringing the grain temperature to just below freezing if it was going to be held over the winter months, but there are some now advocating for the temperature to not be brought below freezing, but rather only in that 35 to 40 degree range,” he said. “If there is an expectation we are going to market that grain during the winter, we might leave the grain temperature in that 35-40 degree range would be the best goal, rather than bringing it down below freezing.”

Moving grain

Most of the grain conveyor manufactures now have tube or belt conveyor systems that don’t have the abrasiveness of augers.

“The primary point where we see damage occurring is on augers that are running partially full and at full speed, or where the flighting is worn and you have a lot of pinch points,” Hellevang explained. “If you have a new auger and you are running it full, probably the amount of damage you experience is acceptable.

Falling grain

Seed damage can also occur if you are dropping beans 40 or 50 feet onto a concrete bin floor. That damage will continue to occur as a cushion of grain develops, although to a lesser degree, Hellevang said.

To minimize this damage, a piece of equipment called a “bean ladder” is used. This zig-zags the flow of grain and slows it down to lessen the impact of the fall.

Finally, Hellevang stressed grain storage time is based on whole, sound kernels, and if the kernel breaks, that exposes the carbohydrates and starch inside the kernel and makes it more susceptible to spoilage. The more broken kernels and cracked kernels the more potential there will be for mold growth and spoilage of grain in the storage facility.

“The less mechanical damage we can do the better it is going to be,” he said.


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