Plus, some helpful substitutions.

While staying at my grandparents’ house last weekend, I was craving pancakes—until I opened the baking cupboard and found a jar of baking soda with a label from the early 2000s. Could it still work?

Baking soda loses potency for baking after 6 months, but it's safe and useful for other purposes. Test baking soda with vinegar to check effectiveness; fizz means it's fresh. Use expired baking soda ...