How should flour be stored?

The primary change which can occur in flour during storage is oxidation of fat, primarily in the germ, when flour is exposed to the air.  This can result in a rancid odor and flavor, especially in whole wheat flour.   Flour should be stored in airtight containers to prevent it from absorbing moisture.   It should be stored at temperatures no higher than room temperature in a dry well-ventilated place for no more than 6-8 months.  It can be refrigerated for up to 1 year.  It can be frozen indefinitely. During hot weather, store it in the refrigerator if not kept in the freezer.   After it has been frozen, flour should be brought to room temperature before using it to make yeast breads as yeast is very temperature-sensitive. Whole wheat flour should be stored in a moisture-proof, vapor-proof plastic bag or tightly sealed container in the refrigerator or freezer  because the germ contains polyunsaturated fat making it susceptible to rancidity.
 
Source(s):  
extension.missouri.edu. “Using and Storing All-Purpose Flour.”