How long does opened baking soda last?

Once opened, baking soda (sodium bicarbonate) has an indefinite shelf life. However, it may lose some of its potency over time, especially if it is exposed to moisture or air. To maintain its freshness and effectiveness, store baking soda in a cool, dry place in an airtight container. Keeping it in the refrigerator or freezer can also help prolong its shelf life.

While opened baking soda doesn't truly go "bad" in the sense that it becomes unsafe to consume, its leavening power (ability to cause baked goods to rise) may diminish gradually over time. If you notice that your baking soda has lost its potency, you can use a bit more of it in recipes or consider replacing it with a fresh box.