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How to Tell If Flour Has Gone Bad (And How to Make It Last Longer)

How to Tell If Flour Has Gone Bad (And How to Make It Last Longer)

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Do you even believe us when we say that flour can go bad? I mean, after all, it’s dry and is made up of only a few ingredients—what on earth could spoil?

Here’s a new flash for you: flour, though seemingly immortal, doesn’t last forever! It can still go bad; and even if its shelf life is long, you may need to toss away that five-year-old bag.

But don’t take it from us, let’s see together how long flour lasts, how you can tell if it’s gone bad, and how to store it properly. Ready?

How To Tell If Flour Has Gone Bad (And How To Make It Last Longer)

How to Know if Your Flour Has Gone Bad

There are 4 sure-and-fire ways to know if your flour is no longer usable. Take a look:

1. A Hard-to-Miss Odor

All-Purpose Flour In A Measuring Cup

Smell is what you want to be on the lookout for. A rancid, sour, or musty smell is your go-to tell that your flour has gone bad. 

Normally, flour has no odor at all or just a slight nutty smell. So when the bag smells all of a sudden, time to throw it out! 

And don’t worry: the smell won’t be too faint or anything. You see, rancid flour is often described as having a rubber scent or one that’s similar to play-dough.

You can bet that that smell will hit you as soon as you open your flour jar or bag.

2. Passed the Expiration Date

We know this one’s a no-brainer, but you’ll be surprised how many people don’t keep a close eye on the date. So, check your expiration dates and see if the flour is still okay.

These expiration dates are typically estimated based on the flour being stored in a dry, cool place. This doesn’t necessarily have to be a fridge but it should be somewhere that isn’t that hot or humid.

Pro tip: Expiration dates and ‘best-by’s are simply estimates. A bag of flour may still be good for a few months after the printed date. So long as it doesn’t show any of the signs I cover here, you’re golden!

Another pro tip: If you like to keep your flour in jars rather than hold on to the bag – stick a label on the jar and write down the dates before you throw away the bag.

3. Color Has Changed

Various Flours In White Bowls On Counter

The color of flour should never change—that’s a golden rule. 

If you have white all-purpose flour, it should always be white and fluffy. Whole wheat flour should always be a tannish brown. An almond flour should always be the off-white color of almonds.

If your flour changes color to anything other than its original state, it’s safe to say that it’s gone bad!

Wheat flour with a yellowish tinge, for example, may have bad oil seeping out of the grains. If your corn flour has a bluish hue, it may be starting to grow mold.

4. Is Home to Flour Beetles

Red Weevil Crawling In Flour

In addition to the oils in the flour itself going bad, you also need to watch out for flour beetles, also called weevils.

These are tiny bugs that live inside flour, laying eggs inside the grain. The gees then open up and the small weevils will happily eat the flour until they are fully grown—this cycle will then keep repeating.

If you have weevils in your flour, chances are you’ll see them moving the moment you scoop into the flour. 

They may not be immediately visible on the flour’s surface as they tend to burrow inside the grains, so you’ll need to push the flour around in order to see them.

Interestingly, weevils are completely harmless if accidentally consumed. Other than being unappetizing, these bugs are nontoxic and won’t have any health effects at all. They’ll die instantly in the oven and you may not even notice that they are there. 

That’s why some people recommend just sifting the bugs out in order to keep the flour. I think that’s gross – but hey, do you!

Why Does Flour Go Bad?

Now, that’s the million-dollar question – why, indeed?

Flour isn’t just salt and baking powder—though, those two are long-lasting ingredients! Flour also contains fats and oils that give it flavor and make the dough turn soft.

Those fats and oils are the culprits behind flour spoiling. And naturally: the higher the content of fat in your flour, the faster it’ll expire.

PSA: When flour goes bad, that means those fats and oils have become old and rancid—and as such, are no longer edible. So, do yourself and your family a favor, and stay away.

How Long Does Flour Last?

Glass Jars With Baking Ingredients In Pantry

Different kinds of flour have different shelf lives. Let’s go through them one by one:

1. White Flour

White, all-purpose flour will be able to last longer than any other flour as it’s a highly processed, very refined grain. Let’s break it down:

A grain of wheat consists of three main parts: the germ, the bran, and the endosperm. When making white flour, the germ and bran are removed from the grain, leaving behind only the endosperm. This part of the wheat is quite dry and contains few nutrients.

Fewer nutrients and minerals mean fewer aspects of the flour to spoil. That’s why white flour will last the longest on the shelf (and also why it’s considered to be one of the least beneficial flours health-wise).

2. All Purpose Flour

All-purpose flour has a general shelf life of 1 year when stored in a pantry – or up to two years when kept in the refrigerator. Let me tell you why:

This flour type is less processed. Once the germ and bran are left on the wheat, the shelf life decreases tremendously. The fat and fiber, along with many of the other vitamins and minerals, will spoil when kept on a shelf for too long.

3. Whole Wheat Flour

Whole wheat flour only has a shelf life of one to three months—a significant drop in time when compared to white flour.

Why? Because whole wheat, and also whole grain, flour contain bran and germ; both of which are highly susceptible to spoilage within a short period. The oils in this flour degrade at a faster rate, resulting in quite a short shelf life.

4. Alternative Flour Types

All alternative flours have a reduced shelf life. Again, that’s due to the vitamins and minerals in the flour components that have the potential to go bad.

Oat flour, for instance, will last about three months when stored in a pantry; as will coconut flour, buckwheat flour, and other nut flours. 

Want to double the shelf life on any of the flours above? Stick with me and we’ll get into that in a second!

How to Store Flour: All Types

While it’s easy to just keep flour in the bag that it came in, rolling the top over and putting it in the pantry, this method really only works if you use your flour frequently.

If you tend to have a bag of flour hanging around for several months, you may want to consider a better method of storage. Here’s what I recommend:

First, put the flour in an airtight container. A plastic or glass container with a tight-fitting lid is the best option. Next, place the flour container in the fridge.

Keeping it in a cold, dark place will actually double the shelf life of the flour, preventing any oils from going bad.

In addition, weevils cannot survive in a fridge, so there’ll be no bugs in your flour either! A much better storage idea to increase the life of your flour.

What Happens if You Consume Bad Flour?

If you suspected your flour was bad but used it anyway, what could really happen? What exactly are the side effects of consuming bad flour?

Sorry to say, my friend, but consuming rancid flour can actually be harmful. 

When flour goes bad, it starts to contain mycotoxins. While fine in the short-term, consuming too many mycotoxins can cause long term health issues like cancer, kidney damage, and reproductive disorders.

While you would need to consume a large amount of bad flour for these side effects to really take place, it’s better to be safe than sorry! 

Simply avoid using rancid flour and buy fresh new flour instead.

How to Bake with Bad Flour

Rolling Pin On Top Of Pizza Dough With Flour

If you happen to bake once or twice with rancid flour, you probably won’t notice any harmful health side effects – but your food will definitely suffer. 

After all, flour that has gone bad will give your food a sour or musty taste.

So, even though the food you made is fresh, it won’t smell or taste fresh. The bad flour will transfer its taste directly to whatever you’re cooking.

In addition, if you’re using a self-leavening flour, the leavener in the mix may have also gone bad—or at the very least, lost its effectiveness. 

Whatever dessert or baked goodie you’re trying to leaven will fall flat as the flour is too old for it to function properly. 


Still got flour-related questions on your mind? Let’s answer them!

Can I use expired cake flour?

That depends on what you just learned from me. If the cake flour shows none of the signs of spoilage we covered, then it should be more than safe to bake with and consume.

We can’t say the same for the taste, texture, and how it’ll work with you in the oven, though.

Is 2-year-old flour still good?

Not exactly. Flour is still good for up to four to six months after its expiration date has passed—a year, maybe, but that’s pushing it.

These numbers are provided, of course, that you stored the flour properly and kept it in a dark, dry, cold place. If not, your odds of the flour still being usable after 2 years decrease.

Bottom line is: if it isn’t showing signs of mold and bad odor after 2 years, it could be usable. Although I say that’s highly unlikely.

Can you eat expired plain flour?

As agreed, expired flour is still safe to consume, given that it hasn’t spoiled, changed color and smell, or become infested with weevils. Expired flour will only compromise the taste of what you’re making – nothing more. 

Final Thoughts

Sarah says: Bake more!

Seriously; everyone could use some more baked goods in their lives. And if you’re baking more, you don’t have to worry about your flour going bad any time soon!

That said, you now know how to tell if flour has gone bad, and how to store it so that you don’t have to face such a pesky issue. 

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Sunday 4th of February 2024

I store my flour in a Tupperware container. Should I store that in the refrigerator?

Sarah Bridenstine

Monday 5th of February 2024

If you go through flour pretty quickly (within a few months), you can store it at room temperature with no problem. If you need it to last longer (like six months to a year), the fridge is the way to go!