How long does cornstarch last?
In the pantry, cornstarch keeps for 18 to 24 months from the package date. Once opened, use it within 18 months.
18 to 24 months
from the package date
No guideline
18 months
in the fridge unless noted
Does cornstarch go bad?
Cornstarch is shelf stable, so the pantry time is about quality rather than safety: past it, flavour and texture fade before anything becomes unsafe. The date on the package is the maker's quality promise; the times here count from purchase unless marked "from the package date".
Two numbers to keep in mind: a fridge at 40 F (4 C) or below, and no more than 2 hours at room temperature (1 hour above 90 F / 32 C) for anything perishable.
How to tell cornstarch has gone bad
General signs for baked goods: baking and cooking, the group USDA lists cornstarch under.
- Small moths, beetles or larvae in the flour or grains
- Clumping or hardening from moisture getting into the bag
- Sharp, crayon-like or paint-like smell from oil
- Baking powder that no longer fizzes when mixed with water
- Chocolate chips with a dull grey bloom or waxy smell
More on baked goods: baking and cooking. The times above are quality guidelines, not safety limits; food that shows these signs goes out regardless of the date.
How long do other baked goods: baking and cooking last?
Source: USDA FSIS FoodKeeper dataset (public domain). How we decode the data.