Part of what makes whole wheat flour nutritious also makes it difficult to store. Within this whole grain product is wheat germ, which contains a healthy but perishable oil that time, temperature and exposure to air will eventually cause to become rancid. If you store wheat flour in an airtight container in your freezer you can generally expect it to keep well for about six to 12 months. If you store it at room temperature, however, you should use your eyes, nose, mouth and hands to check for signs of spoilage after only about two months of storage.
Inspect a handful of wheat flour for a change in color and texture. Fresh wheat flour has a light tan color and smooth texture. Wheat flour that is going or is already bad will start to darken and become crumbly as the oil in the flour breaks down.
Smell the flour. Fresh wheat flour has almost no odor, while flour that is going bad or is already bad will have a mild to sharp sour smell.
Taste the flour. Fresh wheat flour has a nutty taste while flour that is going or is already bad has a sharp, moldy taste you will not soon forget.