How long does yeast last?
In the fridge, yeast keeps for 4 months after opening. In the pantry, it keeps for 2 years from the package date. Once opened, use it within 4 months.
2 years
from the package date
4 months
after opening
4 months
in the fridge unless noted
Does yeast go bad?
Yes. The fridge time above is the window USDA gives for good quality; after it, yeast may still be safe for a short while but quality drops and spoilage signs start. 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 yeast has gone bad
General signs for baked goods: baking and cooking, the group USDA lists yeast 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.