What is unbleached all-purpose flour, and what’s it used for?

Fresh-milled flour does not make good baked products; it needs to age.  Unbleached flour bleaches naturally as it ages.  It becomes whiter when it’s stored for several months, allowing natural oxidation to occur. The flour then has a finer texture, and its baking quality is better.    It is best for cookies, thickening gravies, and coating meat or vegetables prior to frying. Flour is a very low moisture product (less than 15%).  In order to maintain its quality, it needs to be stored in an airtight container in a cool (less than70°F) place.   It loses quality, but is not unsafe, beyond the “use by” date. Flour will retain its original powdery form, even when frozen, because there is so little water present in it. 
 
Source(s):
wheatfoods.org.  “Difference in Wheat Flours.”