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Extension > Local Extension Offices > Benton > County Agriculture Educator > Articles > Cold weather raises grain storage drying questions

Cold weather raises grain storage drying questions

University of Minnesota Extension, Stearns County News
November 26, 2014        
           
Source:  Dan Martens, Extension Educator-Crops
University of Minnesota Extension
Stearns, Benton & Morrison Counties

 

Cold weather raises grain storage drying questions
By Dan Martens, University of Minnesota Extension

FOLEY, Minn. (11/21/14) — Some corn was combined late in the fall and some corn in fields may still be combined. Some may be left in fields until spring. One option is dry wet corn before putting in storage. There can be problems with driers freezing up with condensation from moisture from the corn. Equipment needs to be monitored closely for potential problems.

Some people ask about putting cold wet corn in storage and keeping it cold through the winter and drying it in the spring; or perhaps finding ways to feed wet corn. Putting wet corn on top of dry corn in a bin, or putting cold corn on top of warmer corn that was harvested earlier can make things more complicated. Grinding wet corn and storing in bulk bins could lead to frozen ground feed problems. 

NDSU Grain Storage Specialist Ken Hellevang shared some information related to questions asked about handling wet corn that has been harvested and put in storage at cold temperatures. You can find Ken’s information by doing an Internet Search for “NDSU Grain Drying.” You’re also welcome to give me a call for more of this information at the Stearns, Benton and Morrison County Extension Offices. Here’s a portion of Ken’s discussion.

QUESTION: What is the best management strategy for running aeration fans on bins to cool grain without freezing the bin?

The kernels will not freeze together if the corn moisture content is below 24%; and should flow normally. The acceptable moisture content decreases with more foreign material in the corn. I recommend that corn moisture be less than 24% to hold it until outdoor temperatures are above freezing and at or below 21% to hold corn until spring.

Some people are recommending that wet corn be not be cooled below freezing because ice crystals will form in the void spaces between the corn with the moisture coming from the corn. I am not aware of this being a problem again based on extensive experience.

Frosting will occur when moist air comes in contact with a surface that is below 32 degrees. It typically occurs when air from warm corn comes in contact with a cold bin roof and roof vent during aeration. It can occur with corn at temperatures below freezing when warmer air comes through the cold corn. This could occur if the corn at the top of the bin was cold and warm air from corn below is moved through the cold corn as the bin is cooled using aeration. Normally this will occur only in a shallow layer of corn at the top of the bin and only for a period of time until that corn has been warmed by the warm aeration air coming from the warm corn. The amount of frost accumulation expected in the corn increases as the corn gets colder and layer of corn gets thicker. Since corn is a good insulator, the cold layer is normally expected to be fairly thin and the warm aeration air removes the frost.

If the corn is warmer than the bin steel, condensation in the form of frost will occur on the bin roof and bin vents. The rapid drop in outdoor temperature makes this very likely. Running fans with frost-plugged or iced-over roof vents can result in serious bin damage.

Cooling the corn in small steps reduces this potential. The general goal is to cool the corn to just below freezing, so operate the fans only when outdoor air temperature is above 20 degrees. Corn at 22 percent moisture has an estimated allowable storage life of about 60 days at 40 degrees and 30 days at 50 degrees. (We’re not likely to see those temperatures for a while, but we may have some warmer corn deeper in bins.) Cool corn at recommended moisture contents can wait for cooling until appropriate temperatures exist. Ideally the aeration air temperature would be 10 to 15 degrees cooler than the corn. If it is extremely cold, it is best to not run the fan and wait for an appropriate air temperature.

Thanks, Ken.

NOTE: I wish for you a meaningful Thanksgiving observance. It may be especially good to give thanks for family and friends and people we work with who help us keep some heathy perspectives on the circumstances we deal with.  

Contacts

Daniel Martens
Extension Educator, Ag Production Systems
(320) 968-5077
marte011@umn.edu
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