With so many different flours and sugars, storage guidelines vary slightly. Basic flours, such as all-purpose, cake, bread and pastry, have a longer shelf life and are not as likely to go rancid as whole-wheat flours and other heavier flours such as oat, rye and barley. Heavier flours require much cooler temperatures for storage. White and brown sugar last indefinitely, but only when stored properly, making adequate storage conditions just as important as with flour.
Basic Flours
Place the flour in an airtight container.
Mark the purchase date on the outside of the container with a permanent marker.
Store the container or bag in a dark, dry area that maintains temperatures below 75 degrees Fahrenheit. A pantry or basement space works well. The flour should keep for several months; freeze the flour for longer storage.
Heavy Flours
Place the flour in an airtight container.
Mark the processing date -- usually printed on the packaging -- on the outside of the container with a permanent marker.
Place the container in the freezer. Since these flours go rancid quickly, do not store them at room temperature.
White Sugar
Place the white sugar in an airtight container.
Mark the purchase date on the outside of the container with a permanent marker. While sugar has an indefinite shelf life, the longer it is stored, the more change you may notice in its flavor and freshness.
Place the container in a cool, dry, dark area, but not in the refrigerator. Keep the sugar away from areas of strong odors, such as around other strong smelling foods.
Brown Sugar
Place the bulk brown sugar in an airtight container in which it fits well. A lot of air space in the container may allow the sugar to harden.
Mark the purchase date on the outside of the container with a permanent marker. While brown sugar also has an indefinite shelf life, it's best to use it within six months for the best flavor.
Store the container in a cool, dark area.