Once opened, Baking powder keeps about 3–6 months in the pantry. Unopened, it keeps about 6–18 months.
3–6 months opened in the pantry, against 6–18 months sealed in the pantry. Green is what this situation leaves you; husk is what it spends.
| Situation | Keeps for |
|---|---|
| Unopened · pantry | 6–18 months |
| Opened · pantry | 3–6 months |
Air and warmth are what shorten an opened item's life — the right container buys back the days the packaging gives up once the seal's broken.
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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. Those are the general signs for baking & cooking — USDA FoodKeeper v128 publishes no spoilage note for Baking powder specifically. Never taste something to test it — when in doubt, throw it out.