Because whole grains retain their healthful oils, they are more susceptible to oxidation and need to be stored to prevent deterioration. Heat, light, and air can trigger oxidation of the oil in the germ of whole grains.
If you’re shopping in the bulk section, don’t be afraid to sniff the grains, which should have a light sweet scent or no scent at all. If the bin smells oily or moldy, the grains may be rancid.
Once you bring your whole grain home, store it directly in the refrigerator or freezer. You can either keep it in its unopened package or transfer it into an airtight container or plastic zip-top bag.
Since different grains vary in fat content (from about 1.7% for wheat to about 6.9% for oats), the shelf life of the flours made from them varies. In general, most whole grain flours keep well in the refrigerator for 2-3 months, and in the freezer for 6-8 months. It is recommended to keep flour in a sealed container to prevent picking up stray odors and tastes from the refrigerator or freezer.
Grains, because their oil is sealed in the original grain kernel and cannot easily oxidize, can keep much longer than flour. Most will keep for several months in a room- temperature cupboard, and for a year in the freezer. Commercially processed whole grain products such as breads, crackers, and pasta are commercially processed to be shelf stable and can be stored in the same manner as those that are not whole grain. General advice on grains and flour: try to buy what you’ll use in 2-3 months.
Safe Storage, Grain by Grain
Whole Wheat Flour – airtight seal, freezer, 6 months
Oats – airtight seal, freezer, 3 months
Oat Flour – airtight seal, freezer, 2 months Cornmeal – airtight seal, freezer 4-6 months Kernels or Popcorn – airtight seal, freezer, 1 year Rye Flour – airtight seal, freezer, 6 months
Spelt Flour – airtight seal, freezer, 6 months Buckwheat Flour – airtight seal, freezer, 2 months Barley Flour – airtight seal, freezer, 4 months
Brown Rice – airtight seal, cupboard, 5-6 months; freezer, up to a year
Brown Rice Flour – airtight seal, refrigerator, 4-5 months; freezer, up to a year