Baking powder combines an acid (most commonly monocalcium phosphate, sodium aluminum sulfate, or cream of tartar) and sodium bicarbonate, an alkali more commonly known as baking soda. Water (or other liquid) causes a chemical reaction that produces carbon dioxide, which gets trapped in tiny air pockets in a dough or batter. Heat releases additional carbon monoxide and expands the trapped carbon dioxide gas and air to create steam. The resulting pressure expands the trapped air pockets, causing the dough or batter to rise.
Use: Leavening agent to add rise to batters and doughs
Availability: Common grocery store staple
Shelf Life: A few months
Baking Soda vs. Baking Powder
Baking soda, or sodium bicarbonate, and baking powder both work as chemical leaveners; they create gases that cause the rise that gives unyeasted baked goods an airy texture and light crumb. But although they produce the same result, the two ingredients are not interchangeable. Many recipes call for both.
Baking soda, an alkaline powder, is pure sodium bicarbonate; it requires the addition of an acid to create the desired reaction. Often, recipes pair baking soda with buttermilk, lemon juice, or vinegar. The reaction starts the second the acidic liquid hits it, and it fizzles quickly. If you've ever cleaned with baking soda and white vinegar, you know what this looks like. It can also be matched with a non-liquid acid ingredient, such as brown sugar, honey, or natural cocoa powder, plus a non-acidic liquid.
Baking powder contains both sodium bicarbonate and a built-in acid such as cream of tartar, so it can be activated with a non-acid liquid such as plain water. It may also contain cornstarch to absorb moisture. Double-acting baking powder produces a chemical reaction when it's first mixed with a liquid and then again when it reaches 140 degrees Fahrenheit.
Double-acting baking powder, the kind most commonly found in American kitchens, contains two acid components, one activated by moisture and the other activated by heat. This prolonged reaction produces a greater rise and thus, fluffier muffins, cakes, and bread. It also requires less precision of timing, so if you forget to preheat the oven before you mix your batter or dough, it can sit on the counter as the oven heats without falling flat because the carbon dioxide dissipated before you started cooking it. It's a useful ingredient in batters or doughs that must be chilled before they go into the oven as well.
Tartrate and phosphate single-acting powders release gas the instant moisture touches them. So doughs and batters leavened with tartrate or phosphate alone must go into the oven immediately, before all of the carbon dioxide bubbles escape, to achieve the desired rise.
Baking Powder Uses
This pantry staple adds lift to all sorts of baked goods, from cakes to quick bread to pancakes and more. But beyond the kitchen, it can be used similarly to baking soda in other household applications, such as cleaning and deodorizing, or as a water softener. It does cost more than baking soda, so you may want to limit household use to expired containers.
How To Cook With Baking Powder
High altitudes affect the amount of baking powder needed in a recipe because atmospheric pressure changes the reaction of carbon dioxide. The lower air pressure at higher altitudes causes the carbon dioxide to expand more, so you need less baking powder above 3,000 feet to achieve the same result. If you don't reduce the baking powder by 20 to 50 percent, depending on your location, you may end up with a coarsely textured cake or unpleasantly dense muffins.
You must also take care when substituting buttermilk for regular milk when using baking powder, as it upsets the balance of alkali to acid. Buttermilk has more acid than regular milk, which will reduce the carbon dioxide released and thwart the leavening process. To achieve the desired result when using buttermilk instead of milk, substitute baking soda for some or all of the baking powder. For each cup of buttermilk used in place of sweet milk, reduce the amount of baking powder by 2 teaspoons, and replace it with 1/2 teaspoon of baking soda.
What Does It Taste Like?
Baking powder does not add flavor to foods. It simply triggers the chemical reaction that causes your cookies, cakes, and quick bread to rise.
Baking Powder Substitute
If you find yourself without baking powder, you can make your own. For 1 teaspoon of baking powder, mix 1/2 teaspoon of cream of tartar with 1/4 teaspoon baking soda. If you plan to mix your own to store, you must also add 1/4 teaspoon of cornstarch to that ratio, as the cornstarch will absorb any excess moisture in the storage container and avoid a potential premature reaction. Also keep in mind that homemade baking powder is a single-acting version that works faster and at a lower temperature than the double-acting you buy at the store, so put your recipe together quickly.
Recipes With Baking Powder
Baking powder adds leavening power to baked goods that go quickly from the mixing bowl to the oven.
Where to Buy Baking Powder
Double-acting baking powder can be readily found in any U.S. grocery store. Single-acting varieties are increasingly difficult to find in the States, however. If an older recipe specifies tartrate or phosphate baking powder with no directions for substitution, check an imported foods purveyor or order from abroad.
Baking powder loses its potency over time. Once opened, it should be used within a few months. Chefs often recommend proofing your baking powder before you add it to a recipe by measuring 1/2 teaspoon into a cup and pouring 1/3 cup hot tap water over it. The mixture should bubble enthusiastically. If it does not, toss it out or use it for cleaning and deodorizing.
Sealed packages of commercial baking powder have a one-year shelf life if stored in a cool, dry place.