The storability of grain depends on the grain's quality, moisture content and temperature, according to Ken Hellevang, agricultural engineer with the North Dakota State University Extension Service.

Grain moisture content must decrease as grain temperature increases to store grain properly. For example, the allowable storage time (AST) of 15% moisture corn is about nine months at 60° F, five months at 70° and only three months at 80°. The AST is reduced by approximately one-half for each 10° increase in grain temperature. If grain can be kept cooler, then it can be stored at higher moisture contents.

The recommended long-term grain storage moisture content normally is associated with the equilibrium moisture content (EMC) for the grain at a relative humidity of about 65% to limit mold growth at summer storage temperatures. The EMC at 80° and 65% relative humidity is about 13.5% for wheat, 12.2% for barley, 13.1% for corn, 11.2% for soybeans, 7.6% for oil sunflowers and 9.9% for confectionary (non-oil) sunflowers. These EMCs correspond to the general recommended long-term storage moisture contents of 13.5% for wheat and corn, 12% for barley, 11% for soybeans, 8% for oil sunflowers and 10% for confectionary sunflowers.

"Grain with mechanical damage is more susceptible to mold growth and has a shorter allowable storage life than undamaged grain," Hellevang says. "Corn harvested at moisture contents of 25% and higher likely has a higher-than-normal amount of mechanical damage and will have a shorter allowable storage life than corn with limited mechanical damage."




"Temperature sensors are an excellent tool, but remember that they only measure the temperature of the grain next to the sensor," Hellevang says. "Since grain is an excellent insulator, the grain temperature may be much different just a few feet from the sensor and not affect the measured temperature."


"The goal for summer storage should be to keep the grain as cool as possible to limit insect activity and reduce the potential for mold growth," Hellevang says. "Insect reproduction is reduced at temperatures below about 65-70°."






For more information about storing grain, visit