Once opened, Baking powder keeps about 3–6 months in the pantry. Unopened, it keeps about 6–18 months.
| Situation | Keeps for |
|---|---|
| Unopened · pantry | 6–18 months |
| Opened · pantry | 3–6 months |
About 3–6 months in the pantry, according to USDA FoodKeeper v128.
Baking powder is shelf-stable at room temperature: cool, dry pantry, sealed — refrigerating after opening is optional and mainly preserves quality. Refrigerating it mainly preserves quality rather than safety.
Look for: A rancid, paint-like, or musty smell; Clumping, or moisture in something that should be dry; Insects, webbing, or larvae in the package; Faded colour or a lost aroma. Never taste something to test it — when in doubt, throw it out.