Does Flour Expire, And Can It Be Used Past The Best-By Date?

A good pantry cleanout often leads to a wide range of unused items, everything from pumpkin pie filling from Thanksgiving to the healthy version of crackers you promised yourself you were going to eat. Most of the time, tossing away food that's gone past its best-by date is ideal since you don't want to risk becoming ill or ruining a fabulous recipe with ingredients that are just no longer tasty.

Yet, there are some items, like flour, when you don't know if they are okay to use just by glancing at them. However, even if it doesn't look like it, small changes in the texture and quality of flour can change. It's also possible to mold or become a haven for insects if it's sitting too long, especially exposed. Should you use it, assuming you don't see anything in it? This depends on various factors, including the type of flour and how you've stored it. That big bag of flour you meant to use during the holidays could be okay in some situations, but there are some risks to keep in mind.

Your first step is to determine the wording on the actual flour container. If it says "best by," that typically means the quality of the product will deteriorate beyond that timeframe. If it says "sell by," the store should remove it from its shelves and not sell it to consumers as the quality is likely impacted. A use-by date tends to be more stringent, meaning you really should toss it after that point. Flour exposed to air long, moisture, or pests could be at high risk and shouldn't be kept (via CNET).

The type of flour matters. Self-rising, cake, pastry, and all-purpose flours, called refined white flours, should not be used if they are gray or yellow in color or if you notice any moist lumps. Don't use it if it smells sour, either. Whole grain flours are those that maintain the germ and bran when milled and include buckwheat, white whole wheat, and whole wheat flours. These tend to need better air-tight storage to last, per King Arthur Baking. Since it's more challenging to decipher if they can be eaten simply by looking at them, a good rule of thumb is to get rid of whole grain flours if there's any unpleasant odor or they taste off. As expected, don't use these past the use-by date, as they could have spoiled.

The bottom line is you can use older flour if it doesn't look or smell strange, but it's probably best not to make a habit of it as this may sacrifice the flavor and performance of the ingredient.