Out Of Baking Powder? This Easy Substitute Will Work In A Pinch

Baking powder is a staple in most pantries (even if you only use it in your trusty banana bread), but you may be surprised to know that once opened, baking powder has a shelf life of just 6 to 10 months before it starts to lose its leavening ability. Even frequent home bakers can find it challenging to use a whole container in that time frame. If you suspect your baking powder has expired, you can give it a quick test: simply drop a teaspoon into half a cup of boiling or hot tap water. If it doesn't bubble actively, it's time to add a fresh jar to the shopping list.

Here's a simple baking soda substitution. But first, it's worth understanding how baking powder works to give your baked goods a boost.

What is baking powder?

What's the difference between baking soda and baking powder? Baking powder is a combination of bicarbonate (baking soda) and a weak acid that, when activated with the addition of heat or liquid, reacts to form carbon dioxide gas. This adds lift to baked goods, such as muffins, quick breads and cakes.

Commercial baking powder is double-acting, meaning the baking soda and acid react twice: once when mixed with liquid (like in a batter), and a then a second time when heated in the oven. This two-step process acts as a baking insurance policy, making the time between mixing and baking less critical to determine how much baked goods will rise.

Baking powder is typically used in recipes that don’t contain an existing acid (such as yogurt, buttermilk, molasses or cocoa) that baking soda can react with (the baking powder provides the acid). You'll also see baking powder used in combination with baking soda to ensure batters and doughs rise sufficiently in the oven.

How to make a baking powder substitute

When a baking mood strikes, but there’s no baking powder on hand (or yours is well past its best-by date), use these two ingredients to make a quick DIY substitute, and save yourself a trip to the store.

For one teaspoon of baking powder:

Combine 1/4 teaspoon of baking soda and 3/4 teaspoon of cream of tartar.

This substitute is single-acting, so it will not react in the oven to create additional leavening as a store-bought double-acting baking powder would. For best results, simply minimize the time your doughs and batters sit around before baking by placing them in the oven immediately following mixing. Keep in mind that the equation doesn't quite work in the reverse: you can't substitute baking powder for baking soda.