The shelf life of flour depends on the type of flour, how it was processed, how long it was stored before you purchased it, and the conditions under which it was stored. In general, the cooler and drier the storage conditions, both before and after purchase, the longer it will retain its optimum flavor and performance.
How To Properly Store Flour
Keep flour in moisture-proof packaging.
Transferring it to an airtight plastic or glass container is a good idea, both for prolonging shelf life and for deterring weevils and mealy moths. Whole grain flours should be stored at cool temperatures: below 70°F, and preferably between 40°F and 60°F, to prevent the natural oils in the bran and germ from going rancid.
You can store them in your refrigerator, or even your freezer, if you have space available.
Although at its peak when used within six weeks of being ground, whole grain flour that has been kept cool will perform well for up to three months.
Refined flour has a longer shelf life since most of the oils in the grain are removed during refinement. It can be stored in an airtight container at temperatures up to 75°F (no hotter!) for a couple months; refrigerating or freezing will extend its shelf life for up to a year. For better results when baking, warm any flour stored in a refrigerator or freezer to room temperature before using it.
Regardless of whether it’s refined, the sooner flour is used, the better. Old flour just can’t perform at the same level. Off odors, dampness, or excessive dryness indicate that flour is far beyond its prime, as do off flavors or poor volume in baked goods.
But don’t wait for these obvious clues that it is time to toss out old flour. Rather, buy only the amount of flour you think you’ll use within a couple of months. Many brands print expiration dates on the package, so consult these to ensure you’re buying the freshest possible flour, and use the flour by that date.
Reprinted with permission from The Essential Good Food Guide by Margaret Wittenberg, copyright (c) 2013. Published by Ten Speed Press, a division of Random House, Inc.