Iowa farmers are now well into harvest, corn before beans in many cases. This is yet another unusual situation. A lot of corn has been harvested early this fall with high outside temperatures, in the over 80 and 90 degree ranges, and it was dried in the same conditions. This means corn is now in bins at much higher temperatures than normal.
"Early harvested corn will require at least two additional cooling cycles to reach the desired eventual grain temperature of 40F or below," says Charlie Hurburgh, an Iowa State University grain quality expert and professor of ag and biosystems engineering. "The weather forecasts indicate we will have chances to run the fans and cool the corn in the bins next week."
COOL IT: Early harvest of corn this fall will require additional cooling cycles to reach desired temperatures in your bin. Weather forecasts predict cooler weather this coming week, providing opportunities to run the fan and cool your corn.
You need to cool down this warmer than normal grain the right way
Follow the proper procedure to cool this warmer-than-normal stored corn down the right way this fall, advises Hurburgh. It starts with making sure you understand what a cooling cycle is and what you need to do. What is a cooling cycle? "A cooling cycle is moving a cooling front completely through a bin of grain and it is done when the average outside temperatures are 10 to 15 degrees F below the grain temperature," he says. How long will that take? It depends on the size of the fan you are using. With 0.1 cubic foot per minute per bushel of aeration, this takes about 150 hours; with 1 cfm/bu, about 15 hours is required.
Safe fall storage means you need to be progressively lowering the grain temperature in cycles, he explains. Because the shelf life of the grain in a bin is temperature dependent, it is important to begin these cycles as soon as a 10 to 15 degree temperature drop can be achieved. With higher initial temperatures, at least two additional (beyond normal) cycles will be needed. If the grain has to wait in the bin for a month to be cooled, the shelf life will be reduced and future spoilage is much more likely to occur.
Update on 2012 grain drying, handling and storage management issues
Quality of grain harvested is going to vary widely this fall, even in the same field. You can expect high and low moisture blends to be going into the combine's grain tank in the same pass through the field, says Hurburgh. Dryers will not equalize variability. Even after cooling and aeration of the dried corn, there can be four percentage points or more in moisture variation among kernels. Moisture variation means shorter shelf life and more storage risk.