Answers (1)
"Expired" doesn't mean anything. The date is required by US law, but there is no definition of the meaning. Food does not go bad just because it is past the date printed on the label. Baking powder is a mixture of chemicals, and the only way it goes bad is if it is exposed to high humidity. It has a dry acid and a dry base, so when it gets wet they neutralize each other and produce CO2 which raises your bread. If the package has not been opened, it stays good forever. After the package has been opened, you put a small amount into water and watch for it to fizz. Then you can use it. If it does not fizz, you have to throw it out.