If you’ve just fished a half-finished bag of cake mix out of the kitchen cabinet and you are now wondering:
Has this gone bad? How long is this stuff meant to last?
Then you’ve come to the right place.
In this guide, we’re talking about cake mix: how to store it, how long it lasts, and how to tell if it’s gone bad.
TLDR: Cake mix will last a few months after its best-by date as long as you’ve stored it in a cool, dry place. Plus, opening your bag won’t really change how fast it degrades.
How To Tell If Your Cake Mix Has Gone Bad

As for unopened cake mix, the packaging acts as a seal against moisture, bacteria, and air. Therefore, you should check for any problems, like tears or holes.
If you find any problems with the seal around your cake mix, proceed with caution.
With opened cake mix – or cake mix that has broken packaging – check for mold and insects. You also want to look for clumps, a sign that moisture has got into your cake mix. A weird, sour, or musty odor is a bad sign, too.
If your cake mix exhibits any of these signs, you should bin it.
However, the above signs are for cake mix that has gone bad. It’s more likely that your cake mix isn’t actually bad, just old and deteriorating in quality. More on that later.
The key takeaway is that you should use your cake mix before the best-before date, if at all possible. That’s because baking mix includes leavening agents, like baking soda, which lose strength over time, meaning you’ll come out with a flat cake!
It’s basically impossible to tell if the leavening agents in your cake mix are old, so you’re better off buying yourself a new pack of cake mix.
How To Store Cake Mix

As soon as you’re home from the grocery store, you should put your cake mix in a cool, dry, dark place. Think cupboard or pantry.
The key thing is to keep your cake mix away from light and heat sources, which could cause your cake mix to go off prematurely.
Moisture is also an enemy of cake mix. It harbors bacteria and causes clumping – either way, your cake mix will have to be chucked. Therefore, consider storing your open cake mix in an airtight container in the pantry to keep it sealed.
How Long Does Cake Mix Last?

Technically, your cake mix will still be good for 4-5 months past its expiration date.
However, you really shouldn’t use cake mix beyond three months after the recommended date because it gradually loses its effectiveness. A 6-month-old cake mix may look fine, but your cake will turn out flat and stodgy.
The Key Takeaways On Cake Mix
As you have discovered, storing cake mix is easy.
All you need to do is chuck your cake mix in the cupboard, transfer it to an airtight container once opened, and finish it before the expiration date.