Flour can go bad after six to eight months, if stored in the pantry. Flour can be kept for years in an air-tight container in the freezer at 0 degrees Fahrenheit.
The enemies of flour are heat, light, moisture and pests. Keep flour sealed in a plastic bag with the air squeezed out, or keep it in a sealed glass jar. Store flour in a cool, dark place such as a cupboard. If the kitchen is too warm, store the flour in the refrigerator or freezer. Do not store flour near strong-smelling foods, such as onions or garlic, as it can absorb the odors.