According to Benson protecting the commodity should be a higher priority than creating a quick-fix storage solution. “Recently we’re seeing more people store grain in a bin rather than using temporary storage spaces so they can monitor it better year-round,” Benson says. “Long-term storage is advantageous because we’re dealing with $5/bushel for certain grains, so it’s more important to protect it now than it has been in the past,” he adds.
Chant recommends regular cleaning of grain storage bins to ensure the grain remains in the best possible condition. “You shouldn’t go more than three years without completely emptying and cleaning the bins. We’ve seen elevators hold grain for up to five years and suffer serious consequences,” he says.
But using a properly cleaned storage vessel is only a part of keeping grain high quality. Using effective aeration techniques elongates the time grain can be stored before spoilage occurs.
Keeping dry and even wet grain for a long period of time is relatively easy, if correctly aerating the product. Aeration aids in maintaining a consistent relationship between the grain temperature and the outside air temperature. Maintaining this equilibrium will minimize moisture migration and deterioration rates. An aeration system allows the operator to bring the grain to the desired temperature using either outside or ambient air.
Although finding the perfect grain temperature for the job can be exacted to a science, a general rule of thumb is the cooler the grain, the better. Bill Sturtz of Boone Aeration outlines the advantages of keeping grain at a low temperature. “Cool grain is not subject to damage by insect and mold activity. Those quality barriers become more active once the commodity hits 85 F. Ideally, the grain should be kept above freezing, but as cool as possible,” says Sturtz.
Chant says the target temperature guidelines for corn and beans is below 48 F and wheat is below 56 F.
Factors like seasons, type of grain, duration of time storing and geographical location all determine how to achieve the prescribed temperature. “Twenty-five percent moisture corn arriving at an elevator in Georgia in August poses different issues than 25% moisture corn arriving at an elevator in Minnesota in November,” Chant says. “The corn arriving in Georgia will undoubtedly require the use of fans to safely hold the corn prior to grain drying and long-term storage.”
However, cooling is easier in some regions because of the climate. For example, “typically in the Upper Midwest the crop is harvested in the fall and the temperature must be brought down, which is done naturally at that time of year as the outside temperature declines to 35 or 40 F,” Sturtz says.
Long-term storage that crosses seasonal boundaries requires extensive planning. Charts, such as the one Chant uses (on pg. 26), can help grain storage facilities determine how long they may safely store corn at various temperatures and moisture contents.
Avoiding unstable grain conditions is the prime objective of a successful aeration system. Grain stored above 75 F and 30% moisture content is extremely unstable, and will spoil rapidly.
Benson warns that effective management is half the battle in ensuring an aeration system will do its job. “You can design the best products and possess all the knowledge in the world, but without diligent management, it won’t make a difference,” Benson says.
An automatic aeration program, which uses fans that are programmed to keep the grain at a certain temperature, can be an effective way of managing bin aeration. “Recent dramatic increases in commodity pricing has made the customer more willing to spend money on a better aeration system because the cost of the update is more than offset by the added protection from better aeration,” Chant says.
After taking all the proper measures to ensure proper grain drying, storage and aeration, the last thing an elevator wants to encounter is a pest control problem. It’s nearly impossible to altogether eliminate the presence of insects since they easily enter the bin through natural building openings, shipments and ventilation ports, but it’s in the elevator’s best interest to try and minimize the situation.