does baking powder go bad
Baking powder does expire or become un-effective after a period of time. To test if your baking powder is still useable, place a quarter teaspoon of powder into a cup of very hot water and wait for a reaction. If no reaction occurs, toss it out.
Baking powder needs to be fresh in order to work correctly. It will not ruin, but there should be a use by date on the container that will insure that it has not lost its ability to leaven the food.