Is One Expired Ingredient The Cause Of Your Sinking Cake?

When it comes to baking, the ingredients in your cake batter do much more than just add flavor. They're necessary for the chemical reactions that transform those simple ingredients into a moist, fluffy cake. If you find your cakes never quite turn out the way you want them to, then before you start blaming the recipe or your oven, consider another likely culprit — that container of baking powder that has been hanging out in your pantry for longer than you can remember.

Since most recipes only call for 1 to 2 teaspoons of baking powder, if you're not someone who bakes regularly, it can take quite a while to use up an entire container. That means there's a good chance your baking powder has expired. And, since it doesn't really develop any kind of smell or visual indication it's gone off, it can be impossible to tell when you're just glancing at the jar of white powder as you toss a spoonful into your cake batter.

Even though baking powder is a dry ingredient and seems like it'd be fine in your pantry for ages, it's actually only at its best for about three to six months, depending on whether the container is opened or not. Since baking powder's primary role is as a leavening agent, if it's not working properly, then your cake will sink and have a much denser texture.

How to tell if your baking powder is expired

The first rule of using baking powder is to always check the expiration date, but what if it's still wreaking havoc on your cakes despite not being technically expired? There's a very simple way to test the freshness of your baking powder. The substance doesn't kick off those leavening chemical reactions until it comes into contact with water or heat, depending on the type of baking powder you're using.

So, to tell if baking powder is expired, complete a quick and easy test that introduces both of those elements. Place a small spoonful of baking powder in a bowl, top it with a splash of boiling water, and observe the reaction that takes place. If your baking powder is still working properly, it should bubble up in response to that liquid and heat. If nothing occurs, you need to grab a new jar of baking powder before attempting another cake. And this isn't just an issue for cakes — expired baking powder will give other baked goods, including cookies, a denser texture. 

How you should use baking powder depends on the recipe, but don't be tempted to double the quantity in an attempt to increase the efficacy — adding too much can change the cake's texture by incorporating too many bubbles and holes, and it could make your baked good taste bitter. Instead, to keep baking powder fresh for as long as possible, store it properly in an airtight container away from sunlight and heat.