- The precise answer to the question ? How long does baking soda last once opened? depends to a large extent on storage conditions; store in cool, dry area and keep package tightly closed.
- Time shown is for best quality only - in most cases, opened baking soda will not spoil, but it will lose its potency over time and not perform as intended.
- To test whether opened baking soda is still potent enough to be effective: add one teaspoon of baking soda to 3 tablespoons of vinegar - if mixture bubbles, the baking soda is still potent enough to use.
- ? Best By, ? Best if Used By, and ? Use By dates on commercially packaged foods sold in the United States represent the manufacturer's estimate of how long the product will remain at peak quality - in most cases, the baking soda will still be safe to consume after that date, although it will lose potency over time.
Sources: For details about data sources used for food storage information, please click here