Years ago, I was at a friend’s house and I wanted to make some chocolate chip cookies. When I went digging in her pantry, I found baking powder that had expired many, many years earlier. I tossed it, ...

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?