How to Store Flour Properly

Keeping Your Flour Fresh and Bug-Free

Stacks of flour bags
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How many times have you reached into your cupboard only to discover that the flour you bought last month is crawling with bugs? Or smells rancid? In these cases, you need to throw it out. But there are ways to prevent bug infestation and flour going bad from happening.

The bugs we find in flour and other grains are called weevils. The female weevils actually lay eggs inside the grain kernel, and between one and five months later the egg hatches. So if you find these bugs in your flour, chances are the eggs were there before you purchased it. Thankfully, a few simple steps will help prevent bug infestations, as well as keep the flour fresh, lasting for to seven months.

How to Prevent

By using the right container and putting the flour in the right place, you can avoid that nasty discovery of creepy crawlers in the bag of flour, as well as that foul odor (moisture causes the flour to turn rancid). All you need are sturdy, food-grade plastic bags and food-grade containers with lids found online or in stores, the freezer, and a cool, dark spot. Follow these steps for fresh flour every time:

  1. Put the container of flour in strong, food-grade plastic bag. If the flour bag is packaged in paper, put the whole bag inside a food-grade plastic bag.
  2. Remove excess air from the bag and seal tightly.
  3. Freeze the flour for two days—48 hours—to kill off weevils or insect eggs in the flour.
  4. Pour the flour into a food-grade plastic container with a tight-fitting lid. Keep in cool, dark place to prevent insects from getting at the flour and to prevent sunlight from spoiling the flour.

Do You Have Bugs?

If you aren't sure if your flour is infested with weevils and want to know before following any of the steps above, there is an easy to way to detect if you have flour mites. First, look for a sand-like substance on the top of the flour. If you see a brown dust on the surface, this means that the flour has mites. Although the weevils are so small and light-colored they can go undetected, they do have brown legs. So what you are seeing is the collection of dead and alive bugs along with their waste. If you still aren't sure, rub a pinch of the flour between your fingers—if there are weevils it will give off a minty odor.


  • Keep the flour in the refrigerator to prevent spoiling.
  • Keep your storage area clean to prevent insect infestation.
  • Freeze multiple 5-pound bags of flour individually and store in food-grade plastic tubs with tight-fitting lids.