Did it snow last night? If it did, is there snow on the roof of your grain bins, with grain inside? If all bins are covered with snow but one, that bin could be in trouble. The grain is likely warmer than normal because it’s out of condition.
Dan Arnholt, Columbus, spent years working with farmers on the principles of grain drying during his previous career with an electricity provider. Today, he farms with his wife and son.
“Since it was a warm fall, grain inside bins may have stayed warmer than normal,” Arnholt says. “If you haven’t paid attention to the temperature inside your bins, you should now. It’s important that grain is cooled properly for winter storage.”
Indiana Prairie Farmer asked Arnholt to explain the cooling process. Here are questions and answers related to cooling grain down properly. This is Part 1 of a two-part article.
IPF: Why is it important to pay attention to corn in the bin over the next few weeks?
Arnholt: The fall of 2016 was extremely warm. As grain entered the bin for storage, the average daily temperatures were in the 60 to 70 degrees F range. Even though the grain was cooled for storage, it would have been no cooler than the outside temperature at that time. Grain is a good insulator. It will not change temperature in the middle of the bin unless air is moved over it.
IPF: What happens if you ignore the temperature difference that now exists?
Arnholt: As the outside temperature drops, the outside of the bin cools down while the inside of the bin stays at the same temperature as it was at the end of the cooling period. This temperature difference causes an air current to flow inside the grain [mass]. The cold air drops along the outside of the bin, then warms up and travels up to the top center of the bin. This causes moisture to collect at the top center of the bin. The grain there will start to go out of condition unless it’s cooled down by aerating the grain.
IPF: What is the procedure for cooling down corn?
Arnholt: The purpose of aeration is to cool the entire grain mass to the same temperature to prevent air currents from developing. Cooling down a bin of corn takes long hours of fan operation or large amounts of airflow. A typical bin dryer fan has 0.5- to 1-cubic-foot-per-minute-per-bushel capacity. To lower the temperature 10 degrees F if the bin fan has 1 CFM, you would have to run the fan for 20 hours.
The typical storage bin fan has 0.1- to 0.25-CFM-per-bushel capacity. To lower the temperature the same 10 degrees with a fan size of 0.25 CFM would mean running the fan for 150 to 200 hours. That’s roughly seven or more days, running the fan 24 hours per day.
IPF: How long do you keep cooling the grain?
Arnholt: Step down grain temperature in 10-degree increments until grain is at an average temperature of 35 to 40 degrees F. If you maintain that temperature uniformly throughout the grain mass, it will keep through spring.