Per USDA FoodKeeper
On the counterCounter
18 months
cool, dry place
In the fridgeFridge
Not needed
shelf-stable
In the freezerFreezer
Not needed
keeps without freezing
On the counterCounter
18–24 months
cool, dry place
In the fridgeFridge
Not needed
shelf-stable
In the freezerFreezer
Not needed
keeps without freezing
Quick answer
Yes. Cornstarch lasts 18 months in the pantry. After that, or sooner if stored badly, it spoils: watch for the signs below.
How to tell if cornstarch is bad
Smell
Musty, sour or rancid odour.
Texture
Clumping from moisture, or a damp feel.
Pests
Webbing, holes, or tiny insects in the bag.
Flavour
Flat, stale or bitter taste — quality is gone even if it is safe.
Cornstarch past the expiration date
Unopened
FoodKeeper gives unopened cornstarch 18–24 months in the pantry, counted from the day you buy it. "Best-by" and "sell-by" describe quality and stock rotation, not safety; only infant formula carries a federally required use-by date.
Opened
Once opened, the printed date no longer applies. Count 18 months in the pantry from the day you open it.
How to keep cornstarch fresh longer
- Store in an airtight container in a cool, dark, dry place.
- Keep away from the stove and dishwasher, where heat and humidity speed spoilage.
- Write the opening date on the pack.
More about cornstarch
FAQ
How long does it take for cornstarch to go bad?
18 months in the pantry, per USDA FoodKeeper.
Can cornstarch expire?
FoodKeeper gives unopened cornstarch 18–24 months in the pantry, counted from the day you buy it. "Best-by" and "sell-by" describe quality and stock rotation, not safety; only infant formula carries a federally required use-by date.
What happens if you eat bad cornstarch?
Usually an unpleasant taste rather than illness, but discard anything mouldy, rancid or smelling off.
How do you keep cornstarch from going bad?
Store in an airtight container in a cool, dark, dry place.
Numbers on this page come from USDA FoodKeeper and FSIS guidance. Last verified November 2026. How we verify our data · Report a wrong number