The weather is changing, those winter temperatures are leaving and summer temperatures are coming. It’s time to think about the corn that is stored in bins, that is being held into the summer in hopes of taking advantage of a market rally. If the corn is going to be held past the end of May, it’s time to think about warming the grain for summer storage. The temperature of the corn should be raised to 60-70° F. One very important factor to consider before doing this is the moisture content of the corn. Keeping corn into the next summer is something that should be considered and planned for when the corn is dried and put into the storage bin. Corn that is held into the summer should be dried to 14% or below moisture content. If you did not dry the corn to 14% or below moisture content and have not sold the corn because the market has not rallied as you had anticipated, you may want to rethink keeping the corn into the summer.
Corn like any other product has a shelf life, if the corn was dried to 15% moisture and cooled to 50° in September by the end of April 2/3 of its shelf life is used up. Then if the temperature is raised to 60° then the 1/3 shelf life that life that is left equates to approximately 70 days before one  grade is lost. If the corn temperature is raised to 70° then the 1/3 shelf life becomes 40 days. All of a sudden #2 corn becomes #3 corn. That doesn’t help the bottom line, in this time of lower market prices that can mean the difference between profit and loss. [All of this information is based on assuming that the moisture of the grain was tested accurately and that the grain was cooled to 50° immediately.] If the corn had been dried to 14% and handled in the same manner and the temperature raised to 60° there would still be almost a one year shelf life left at the end of May.
I would recommend not raising the corn temperature above 65° if possible. Insect and mold activity seem to start at around 70°. It is also a good idea to seal off the fans at the bottom to stop the natural chimney effect, which, as the air moves up through the corn will warm the corn in the bottom of the bin. Pay attention to what’s going on in your bins, it’s your livelihood.