A calculator that helps peanut handlers and processors determine the right amount of ventilation for their storage warehouses is available on the Agricultural Research Service (ARS) Web site.

Agricultural Engineers Chris Butts and John Smith (retired) at the ARS National Peanut Research Laboratory in Dawson, Ga., and colleagues conducted research to determine proper storage conditions. The result is an online tool to help peanut growers, shellers and others calculate warehouse capacity, dimensions, and headspace ventilation requirements for safe storage of peanuts.

The warehouse ventilation calculator can be accessed at: http://www.ars.usda.gov/Services/docs.htm?docid=7338

When peanuts are harvested, the moisture content is too high for safe storage and they must be cured until the moisture content is below 10 percent. Curing normally occurs at a centralized facility capable of curing between 50 and 200 individual loads at the same time. After curing, the peanuts are graded, unloaded and stored —still in the shell — in a large warehouse until they are needed at the shelling plant for further processing and sale to a peanut product manufacturer.

A typical bulk storage facility will hold between 2,000 and 10,000 tons of in-shell peanuts with a value of $800,000 to $4 million. Under ideal storage conditions, the peanut value will decrease 2-3 percent, but under poor storage conditions, losses can be as high as 10 percent. Good storage practices include adequate ventilation of the space above the peanuts to remove moisture-laden air and prevent condensation.

The calculator gives the recommended airflow rate based on changing the volume of air in the space above the peanuts once every 2 or 3 minutes. The calculator also provides the proper amount of inlet area. By selecting the peanut market type that will be stored in the warehouse, the tool adjusts its calculations to account for the differences among the types of peanuts.

ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.