For flakier pie crusts, moister cakes, and chewier cookies, apply this one rule. Toss out your leavening agents after six months, even if they’re not expired yet. Ingredients like baking powder, baking soda, and yeast may have long expiry dates on the packaging; however, they have very short shelf lives, meaning they will expire pretty quickly and won’t give your baked goods the lift they deserve. You can also buy them in small quantities, so they don’t sit in your cupboard quietly going rancid,