Once opened, Baking soda keeps about 6 months in the pantry. Unopened, it keeps about 2–3 years.
6 months opened in the pantry, against 2–3 years sealed in the pantry. Green is what this situation leaves you; husk is what it spends.
| Situation | Keeps for |
|---|---|
| Unopened · pantry | 2–3 years |
| Opened · pantry | 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 6 months in the pantry, according to USDA FoodKeeper v128.
Baking soda 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 soda specifically. Never taste something to test it — when in doubt, throw it out.