Flour is one of those kitchen staples that you seldom ever run out off. Depending on how often you bake, a 5-pound bag from Walmart can last you anywhere from 3 weeks to forever.
Furthermore, flour is a versatile all-purpose ingredient that features in almost every meal. You can find some form of flour in bread, pizza, pasta, pastry, pancakes, dumplings, and even a cauliflower gratin. As a result, it is a typical grocery shopping behavior to opt for bigger bags of flour in a bid to reduce refill trips.
Hence, every time you reach for that half-empty bag of flour, it is not uncommon to find yourself asking questions like: Is this flour safe to use? How long does flour last in storage? Does flour even go bad?
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Does flour go bad?
Short answer? Yes, especially if not stored properly. Like other cooking ingredients, flour can spoil over time.
One primary reason why flour goes bad is fungal growth. Over an extended period, flour in storage can get affected by microscopic fungus. This fungus then produces mycotoxin—a toxic secondary metabolite that gives bad flour a stale smell. Exposing flour to moisture can further facilitate this process.
Another common reason for the spoilage of flour is weevils—tiny, almost microscopic bugs that infest and lay eggs inside the bag of flour. Weevil-infested flour many also signify that it’s time for a pantry cleanout, as these bugs are notorious for overrunning everything they can find.
However, the use of flour date back to at least 6000 BC, and one reason for its sustained dominance over the century is its considerable resistance to spoilage.
Hence, you can often use flour for extended periods. Flour, especially when stored properly, can last much longer than the Best Before date on the package.
How to Tell if Your Batch of Flour Has Gone Bad
The fastest way to tell if a batch of flour is spoilt is from its smell or taste.
Most good flours typically have little to no smell, while some nut-based variants and other alternative flour can have a slight, sweet odor. Spoilt flour, on the other hand, has a distinctive rotten, artificial smell that is sometimes musty or sour.
Alternatively, if you are still unsure, you can confirm the suitability of a batch of flour by dabbing a pinch onto your tongue. Bad flour has a characteristic unpleasant taste that is hard to miss. Furthermore, any discoloration of the flour is a clear indicator that it is unsafe for use.
To check for weevil infestation, follow this simple test:
- Fill a small clear glass container with a portion of the particular flour batch
- Press the flour down until you get an even, flat surface near the top of the glass
- Leave the container in a warm, bright area for a few hours
- Check back for any breakage in the smooth surface as this confirms the presence of weevils
Bugs aren’t necessarily a sign of flour going bad. However, if you do discover them in your batch, you may want to consider getting a new bag of flour to avoid further pantry infestation.
What Happens if You Use Bad Flour?
The first sign that you use spoiled flour in your recipe is if your baked goodies exhibit an unusual texture.
When flour goes bad, the first component that degrades is the gluten and other organic oils that gives flour it’s stretchy and sticky texture. Consequently, baking with bad flour produces results that are flat and coarse.
Furthermore, foods containing bad flour often reveals a strange rancid taste thanks to the presence of mycotoxins. Excessive consumption of mycotoxins can cause adverse short and long term health issues in both humans and pets.
However, consuming flour that contains weevils is typically not dangerous to human health safe for the yuck factor.
How Long does flour Last?/ Flour expiration table
Knowing the right time to throw food out can be tricky, especially when it comes to dry goods like flour. Many packaged food items come with labels that show a recommended use-by or best-by date. However, when it comes to flour there are other irregularities to consider.
Flour is produced by grinding cereal grains, seeds, or roots to a fine powder. Hence, many different types of flour exist on the market, including wheat, corn, rice, and self-rising flours.
Different flour types degrade at different rates, so the makeup of the flour will be a significant determining factor in how long it lasts. The rule of thumb is that flours with higher oil or fat content like almond flour degrade faster than others like white flour.
Furthermore, when it comes to flour, the best-by date is usually an extremely conservative figure. When a batch is stored correctly, most flours will last significantly longer than that date.
Here is a rough estimate of how much longer than the best-by date some flour types can last:
| Flour Type | Stored in a Pantry | Stored in a Fridge/Freezer |
| Whole-Wheat Flour | 1 – 3 months | 6 months – 1 year |
| White flour | 1 year | 2 years |
| Self-Rising Flour | 4 – 6 months | 1 year |
| Bread Flour | 6 months | 1 year |
| All-Purpose Flour | 1 year | 2 years |
| Oat Flour | 3 months | 6 months |
| Alternative Flours like Banana Flour, Coconut Flour, and Gluten-Free Flour | 3 months | 6 months – 1 year |
How to Store Flour to Extend Shelf Life
The most critical factor necessary to properly store flour is to keep it away from moisture at all costs. Most flours can sit in the pantry or kitchen cabinet without problems. However, ensure that each batch is in a cool and dry area away from any moisture.
Furthermore, after opening a new batch of flour, it is best to transfer the remainder into an airtight container for future use. Vacuum seals help to block out water vapor as well as protect the powder from nearby odors and chemicals that are easily absorbed by flour.
If you have a considerable stash of flour, or you don’t bake that often, consider refrigeration. A fridge or freezer offers significantly more dependable storage. Cooling substantially extends the life of all flour types.
However, remember to use heavy-duty freezer bags to prevent any moisture seepage.