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OSU Extension

College of Food, Agricultural, and Environmental Sciences

November 12, 2019 - 8:22am --

The typical market standard for corn is 15% moisture.   A moisture content of 15 to 15.5% is recommended for corn that will be stored over winter. There was a lot of June planted corn in Wayne County and even some July planted corn.  Grain moisture contents on these fields are in the upper teens to mid-twenties.  Typical November weather conditions are dismal for in-field drying.  Reaching a storage moisture of 15.5% will require propane and a grain dryer.  a common estimate is that is takes 0.02 gallons of propane to remove 1% point from a bushel of grain. If your corn is averaging 25% at harvest, you will need to remove 9.5% to dry it to 15.5%, using 0.19 gallons of propane per bushel or 190 gallons per 1000 bushels.     

This week, I am excerpting some text from a recent OSU Extension CORN newsletter by Elizabeth Hawkins, Extension Field Agronomist specialist, and Jason Hartschuh, Extension Educator in Crawford County on some of the challenges of drying higher moisture corn grain.  The entire article is available on-line at

“Now comes the challenges of drying high moisture corn in high temperature dryers. The high moisture corn will spend more time in the dryer, increasing its chances of browning. The high temperature air over a longer period during fast drying and cooling often creates stress cracks and broken kernels leading to a lower test weight and issues with storage. Most high temperature dryers are run at about 210 F. One way to reduce kernel damage in wet grain is to decrease the temperature below 200 F even though it will take longer to dry. Unfortunately, lower temperatures are not as efficient at drying. It takes 4,000 BTU to remove a pound of water at 150 F but only 2800 BTU at 200 F. Keeping dryer plenum temperatures as high as possible without damaging grain is ideal.

Monitor the grain coming from the dryer for cracks and decrease temperatures until quality is maintained. As temperatures decrease below 40 F, the chances of condensation forming when hot grain is put into storage bins increases. Grain coming out of a high temperature dryer should be at 90-100 F to reduce the condensation potential. If your bins have large enough aeration fans, cooling the rest of the way in bin can also help improve grain quality. When hot grain is fully cooled to 30 or 40 F, the amount of stress cracks increases. During cooler temperatures it is even more important that the corn is cooled at its fill rate or faster. It takes an air flow rate of 12 cfm per bushel coming into the bin in an hour to keep up with cooling.

Increased dryer condensation can also cause issues. As the condensation cools during freezing night-time temperatures, vents may become iced over decreasing efficacy and causing damage. If you are using a dryer bin, these vents freezing over could cause roof damage. To avoid this, leave all access doors open or close with an elastic strap that can act as a pressure relief.   

If your corn crop was frost killed, another layer of challenges has been added. When corn is frost injured, a moisture tester will often read lower than actual grain moisture. The outer portion of the kernel dries faster than the interior. This grain is usually 1-2% wetter, even after drying than your moisture tester reads. In order to handle this, grain needs dried to 12-13% and fully cooled. It also takes more energy per percent moisture to dry this grain. Frost killed corn will have a lower test weight decreasing storage life.  

Even after drying, high moisture corn often has more fines due to more aggressive shelling and drying. These fines increase storage issues leading to corn going out of condition sooner. The fines can fill in voids deceasing airflow, causing hot spots and increased potential for insect damage. These fines can cause issues in the dryer leading to a greater potential for dryer fires. This can be managed in a couple ways. Fines produced in the combine can be removed using a drum grain cleaner before the grain enters the dryer. The high moisture corn is often much more fragile after drying so even if combine fines are removed, there is still a major concern for in bin fines.

The first step to protect grain from most insect damage is to cool it below 20-25 F. Make sure the grain is cooled throughout by taking temperatures 12 inches into the grain at the top from multiple areas of the bin. After cooling bins, they should be cored to remove fines that accumulated in the center of the bin. During coring, about half of the peak in the bin should be removed creating a cone. If a cone is not created, the grain is bridging, and you should NOT ENTER the bin. If you have multiple bins, it is recommended that you sell the corn that was dried from the highest moisture first.


Rory Lewandowski is an OSU Extension Agriculture & Natural Resources Educator and may be reached at 330-264-8722.

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