Understanding Leaveners
A leavener adds gas to a dough or batter creating lift and a more open crumb. Without leaveners, baked goods would be dense and squat. Read on to learn about the two leaveners we typically use in cookie recipes.
Why do so many cookies call for a combination of leaveners? The two work in tandem to create cookies that rise—and spread—to the right degree. Baking powder is responsible for lift since it’s engineered to produce most of its gas after the cookies go into the oven, where the dough sets before the bubbles can burst. But too much lift can mean cookies turn out domed and cakey. Here’s where baking soda comes in: As long as there’s an acidic ingredient in the dough for it to react with, a small amount of baking soda can even things out. Baking soda raises the pH of the dough (baking powder does too, but to a lesser degree), weakening gluten. Weaker gluten means less structure and cookies with crackly tops and the ideal spread.
Baking Soda
Baking soda, or sodium bicarbonate, is an alkali that releases carbon dioxide upon contact with an acidic ingredient such as citrus juice or sour cream. It also improves browning.
Baking Powder
This chemical leavener blends baking soda (an alkali) with a powdered acid and some cornstarch, which keep the first two ingredients dry so that they don’t react. The alkali and acid react to create carbon dioxide when the baking powder becomes wet (say, in a batter) and again when heated, hence the “double action” you’ll see on the label.
Substitution: For every 1 teaspoon of baking powder, substitute a mixture of ¼ teaspoon of baking soda and ½ teaspoon of cream of tartar. Use immediately.
