Can I still use expired flour?

Don't use flour that shows mold or pests - that's definitely a no-go. But otherwise: old flour is usually not a problem as long as the storage conditions were right. The expiration date on flour is really more of a recommendation than a hard rule. If it was stored dry and cool, doesn't smell rancid, and has no discoloration, you can bake and cook with it like normal.

Here's a trick a lot of people don't know: if your flour is older and you notice that baked goods aren't rising as well as usual, just increase the amount of leavening agent (baking powder, baking soda, or yeast) by about 10-15 percent. Older flour loses some of its leavening power over time, and that makes up for it. With pasta, bread, or cake you often won't notice any difference at all - it only becomes a problem if your baked goods consistently don't rise.

Now store your flour better in an airtight container (glass or sealed boxes) and keep it cool - then it'll last much longer without oxidizing or absorbing moisture.

I always store flour in airtight containers and haven't had any problems with it even after half a year, as long as it was really dry. What the others didn't mention: even if the flour is still okay, its leavening power can decrease - you'll especially notice this with flour varieties that have baking powder or with wheat flour type 405 when you're baking, because the dough won't rise as nicely anymore. So check the expiration date, but what's even more important is how it was stored and whether it simply still smells good.

You have to throw out flour with mold, pests, or a musty smell - there's no discussion about that. Otherwise, expired flour really isn't a problem if it's been stored cool and dry. One extra thing worth mentioning: even as flour gets older, it mainly loses its leavening power, not its safety - your bread just won't rise as well, but it won't make you sick.

One thing nobody mentioned: flour loses its baking power over time, especially the protein in it breaks down slowly. So your dough might not rise as nicely as it would with fresh flour. If you're baking a cake where a light, fluffy texture matters, you'll probably notice the difference. With bread or pancakes it's less of an issue.

But the expiration date on flour is really more of a guideline than a hard rule - the others are right that keeping it dry and cool is what matters most. My tip: if the flour is older, just use a bit more baking powder or yeast, depending on what you're making. That way you'll compensate for the lost leavening power. And of course check it first by smelling it and making sure everything really looks clean.