Q: What's the shelf life of baking soda and baking powder?

A: For most purposes other than baking, baking soda has an unlimited shelf life. To test if it's still at its maximum effectiveness for baking, put a few drops of an acid, such as vinegar or lemon juice, in a small bowl and add 1 tablespoon of baking soda. If the soda fizzes immediately, it's still effective. If the fizzing is delayed, keep the soda for cleaning purposes and buy a new box to use for baking.

Baking powder is more likely to lose its potency over time. Check it by stirring 1 teaspoon of baking powder into 1/4 cup of warm water. If it doesn't readily bubble, discard the baking powder and buy a fresh can.

Containers of baking soda and baking powder carry expiration dates. Store them in their original containers in a cool, dry place; be sure to keep the baking powder container tightly closed.