How Long Does All-Purpose Flour Last?

All-purpose flour rarely goes 'bad' in the sense of becoming unsafe, since its low oil and moisture content gives mold and bacteria very little to work with — what actually ends its useful life is usually a musty, slightly sour smell (a sign of oxidation or, less often, mold from moisture getting in), or visible pantry pests like small moths or larvae, either of which means the whole bag should be discarded rather than sifted through and salvaged.

A bag stored in a humid kitchen, or one that's been left open to the air for a long stretch, declines faster than one kept in a sealed, airtight container — moisture is the real enemy here, since it can eventually let mold take hold in flour that would otherwise sit safely on a shelf for the better part of a year. Buying flour in a quantity that'll actually be used within that window, rather than a huge bag that sits half-full for over a year, is a simple way to stay ahead of that slow decline. A quick sniff test is genuinely useful here since flour's decline is mostly about smell rather than visible change — flour that still looks perfectly white and normal can already have developed a faint sourness that's easier to catch by nose than by sight. Transferring flour out of its paper bag into a rigid airtight container as soon as it's opened, rather than leaving it in the original packaging, is one of the more effective single steps for stretching that shelf life toward its longer end.

See All-Purpose Flour's full storage & shelf-life guide (with spoilage signs) →