Extension and Ag Research News


Check Stored Grain Moisture Content

Stored wet grain will deteriorate rapidly at warmer temperatures.

Moisture measurements at harvest may have been in error due to moisture gradients in the kernel, grain temperature and other factors. In addition, the moisture may have changed while in storage due to moisture migration or moisture entering the bin.

“Collect and place a sample in a sealed container, such as a zip-lock plastic bag, warm the sample to room temperature and then check the moisture content,” says Ken Hellevang, North Dakota State University Extension Service agricultural engineer. “If the sample is not warmed to room temperature in a sealed container, remember that the grain temperature needs to be above about 40 degrees and a temperature adjustment must be made either automatically or manually to obtain an accurate measurement.”

Stored wet grain will deteriorate rapidly at warmer temperatures. At 22 percent moisture, corn has an allowable storage time (AST) of about 30 days at 50 degrees, 15 days at 60 degrees and only about eight days at 70 degrees. Therefore, corn at moisture contents up to about 22 percent moisture needs to be kept cool using aeration until it can be dried. Run the fans at night when outside temperatures are the lowest. Cover aeration fans when not operating to limit warm air blowing into the open fan and warming the grain.

“Natural air-drying with an airflow rate of at least 1 cubic foot per minute (cfm) per bushel can be used to dry corn at moisture contents up to 21 percent moisture during the spring,” Hellevang says. “Start the fans when the average air temperature is about 40 degrees, which is occurring now. Drying time will be about 45 days with an airflow rate of 1 cfm per bushel. The final corn moisture content will be about 13 percent to 14 percent.”

At moisture contents up to 17 percent, wheat can be natural air-dried with an airflow rate of at least 0.75 cfm per bushel. Start drying when air temperatures average about 40 degrees.

Immature and lower-quality grain is more prone to deterioration than good-quality grain, so it should be dried to a moisture content about one percentage point lower than good-quality grain. It also needs to be monitored more closely than good-quality grain.

Additional information is available on the NDSU Extension Service grain drying and storage Web site at http://www.ag.ndsu.nodak.edu/abeng/postharvest.htm.

NDSU Agriculture Communication

Source:Ken Hellevang, (701) 231-7243, kenneth.hellevang@ndsu.edu
Editor:Rich Mattern, (701) 231-6136, richard.mattern@ndsu.edu
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