Cooling Stored Grain

Cooling Stored Grain

October 23, 2009

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“These are the worst harvest and grain drying conditions I’ve seen in over a decade,” said Tom Dorn, a UNL extension educator who focuses on grain storage issues. While it won't solve everything, keeping the grain cool may help you avoid a runaway bin full of quickly deteriorating grain.

“Half of the equation in preventing spoilage in stored grain is getting the grain cool and keeping it cool. If you can’t get it as dry as you’d like, at least keep it cool,” Dorn said.

Microbes in the bin generate heat so you need to carry away that heat so it doesn’t build up. The hotter the grain, the greater the respiration by the microbes, and the faster the deterioration of the grain.

Dorn offers some recommendations, in addition to those in previous CropWatch stories (see box), for grain storage under these conditions.

  • This year growers may want to add a small fan to storage bins. For cooling grain above 18% moisture, a minimum of 0.2 cfm per bushel is recommended. This won’t dry the grain, but it can help preserve its quality for the short-term.
  • With conditions as wet and cool as they are this week, you could add some heat to the air flow, but be conservative — no more than 20 degrees for soybeans or 40 degrees for corn. This will cost you more for point of moisture reduced, but will reduce the drying time.
  • Adding too much heat, especially when drying soybeans in the bin, can be costly. Beans give up their moisture more readily than corn and beans on the bottom of the bin can drop to 5% moisture. You’ll be paying for energy you didn’t need to use and, with less water in the grain, you’ll be getting a smaller check at the elevator. (See Harvest Soybeans at 13% Moisture on the Surviving High Input Costs page of the CropWatch Web site.)
  • If you can get corn down to under 17% moisture and 30°F and if temperatures stay cold, you can stop running the fan as long as you monitor the grain at least twice a week and operate the fan intermittently as needed. Open and lean into the access hatch at the top of the ladder, check the air for a moldy odor and for any signs the exhaust air leaving the grain  is hotter than the external air. If you find signs of trouble, run the fan until conditions improve.