Answer:
Does Baking Soda Go Bad?
Baking soda is good indefinitely past its best by date, although it can lose potency over time. You can use a rule of thumb—two years for an unopened package and six months for an opened package. While old baking soda may not produce as much leavening action, it is still safe to eat. Your recipes may not turn out as well, but you can still eat the results.
