The Simple Baking Powder Cake Mistake You're Probably Making

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On the long list of mistakes you can make when baking a cake, not checking the freshness of your ingredients is high on the list. Oh, sure, you know that you shouldn't use expired eggs or milk in your batter, but spare a thought for the baking powder you're about to mix into your dry ingredients. If you're furrowing your forehead right now because you have no idea what we're talking about, take heart — plenty of folks don't realize that baking powder has a shelf life. And, yet, baking powder (and its simpler sibling, baking soda) is at its best for only around six months after opening, and definitely no more than a year. Many folks aren't baking daily unless they have a home cake-decorating hustle, so it's reasonable to expect that your supplies may be a bit, well, outdated.

Regardless of your personal disposition towards the alleged expiration of baking powder — which may just sound like over-cautious horse-pucky to many — your baked goods will tell on you if you use old baking powder. Baking powder is a leavener, which means that it helps your baked goods to rise. Using out-of-date baking powder can make your cakes flat as can be, and dense to boot. Old baking soda will have a similar effect, leaving you with a "dead" product that's not even fit to deodorize your fridge.

You should really be dating boxes of baking powder with a Sharpie when you first open them. If you didn't do it, however, take heart, as there is an easy hack to determine whether your baking powder is still fit to bake with. Simply fill a bowl with hot water and stir in a heaping spoonful of the suspect baking powder. Does the liquid fizzle energetically as carbon dioxide bubbles are rapidly released in a reaction with the water? Congratulations, your baking powder is good to go. If the water is lifeless and nothing really happens, it's time to toss that container of leavener.

Luckily, there are plenty of options, from grocery stores to online. A hearty supply of Amazon Fresh Baking Powder is only a few bucks and a Prime shipping window away. In a pinch, you can even make homemade baking powder with just three ingredients: baking soda, cream of tartar, and cornstarch. Considering how inexpensive baking powder is and how easy it is to replicate, there's really no excuse to sacrifice the downy lightness of your cakes to old, expired products. Some virtuous folks say "waste not, want not," but we're officially giving you permission to ditch your mystery box of opened baking powder and start again fresh. Your cakes — and the people eating them! — will thank you.