Are you getting ready to do some baking, but you're unsure if your baking powder is still good? To find out, drop a teaspoon of the baking powder into a cup of hot water. If it bubbles heavily, the baking powder is still good. If it doesn't, it's time to buy another can.
Why This Works
Most store-bought baking powder products are double-acting, meaning that they cause the ingredients in your recipe to rise twice. The first rise happens when the baking powder comes into contact with the wet ingredients in the recipe. The second rise occurs when the baking powder is subjected to the heat of your oven. By dropping a teaspoon of baking powder into hot water, you're testing both of those reactions.
Make Your Own Baking Powder
If your baking powder didn't pass the test, and you don't feel like running to the store for more, you can make your own. As long as you have baking soda and cream of tartar in the pantry, you're all set. You can make your own baking powder in less than a minute. Unlike baking powder, baking soda needs an acid to activate it, which the cream of tartar (an acid) will do nicely.
Just know that this will give you single-acting baking powder, not double-acting. It will cause your recipe to rise when it comes into contact with the wet ingredients, but it won't rise a second time in the oven. Be sure to get your baked goods into the oven quickly, and don't stir more than you have to so that you get the maximum rise possible out of your homemade baking powder.
Using homemade baking powder could affect the height and density of your finished product, but sometimes slightly shorter, denser baked goods beat a trip to the store.
Other Substitutes for Baking Powder
If you don't have any cream of tartar on hand, you can also use baking soda in combination with another acid, like buttermilk, lemon juice, vinegar, or yogurt to create a baking powder substitute. Just use 1 teaspoon of baking soda and 2 tablespoons of one of these acids in place of each tablespoon of baking powder called for in your recipe.
If one of these acids is already included in your recipe, there's no need to add more. The acid will activate the baking soda.
More Things You Can Do With Baking Powder
Once you've determined that your baking powder is still fresh, or you've replaced it with a new can, use it to make your own self-rising flour and self-rising cornmeal. They only take a couple minutes to make and are quite a bit cheaper than store-bought versions. Finding more uses for your baking powder will also ensure that you use up your next can long before you have to worry about whether it's gone stale.
Also, store your baking powder away from heat and moisture to maximize its shelf life.