The power of baking powder

Baking powder is a staple in most pantries, but you may be surprised to know that once opened, baking powder has a shelf life of just six 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. 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, it should bubble actively, otherwise it’s time to add a fresh batch to the shopping list.

HOW IT WORKS

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, adding 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 second time when heated in the oven. This two-step process makes 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. You’ll also see baking powder used in combination with baking soda to ensure batters and doughs rise sufficiently in the oven.

For one teaspoon of baking powder, combine 1/4 teaspoon of baking soda and 3/4 teaspoon of cream of tartar.

Hot tip: This substitute is single-acting, so it will not react in the oven to create additional leavening as a storebought 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.