Storing: Store all-purpose flour in an airtight container in a cool, dry place for 10 to 15 months; store whole grain flours for up to 5 months. For longer storage, refrigerate or freeze the flour in a moisture- and vaporproof container. Before using a refrigerated flour in yeast breads, bring it to room temperature so it does not slow the rising of the bread.
To Sift or Not to Sift: You usually can skip the sifting of all-purpose flour. Even though most all-purpose flour is presifted, the flour settles in the bag during shipping. So, it's a good idea to stir through the flour in the bag or canister before measuring to make it lighter. Then gently spoon the flour into a dry measuring cup and level it off with a spatula.
You will need to sift cake flour before measuring it.