Since baking soda is a primary ingredient in a variety of cookies, it can be tough to replace in recipes. According to the University of Nebraska Cooperative Extension Service, there is no substitute for baking soda that will work as its precise equivalent. To use a different leavening agent in cookie dough you may need to tinker with the recipe's ingredients to ensure the cookies still look and taste right. However, with a little work using a substitute for baking soda can be a success.
Baking Soda's Purpose
Baking soda acts as a leavening agent by working with acidic ingredients to help cookies rise as they bake. It's often used in cookies because they contain acidic ingredients such as buttermilk, molasses, citrus juice, cocoa or brown sugar. Because of this, using a baking soda substitute will not work on cookies that rely heavily on acidic ingredients for flavor or texture development, such as ginger snaps or lemon cookies. However, baking soda substitutes are likely work better in sugar cookies, chocolate-chip cookies or any other cookie that has a soft, sugar-based dough.
People who need to limit their sodium intake often use potassium bicarbonate as a baking soda substitute in baked goods. It contains the same leavening properties as baking soda, but none of the sodium. Although potassium bicarbonate isn't usually available in grocery stores, you can find containers of powdered potassium bicarbonate in the supplement section of most drugstores since it is sometimes used as a dietary supplement for those with high blood pressure and acid reflux issues. You don't need to adjust the ingredient amounts when substituting potassium bicarbonate for baking soda in cookie recipes. If the recipe calls for 1 teaspoon of baking soda, for instance, add 1 teaspoon of potassium bicarbonate instead.
You can use baking powder in place of baking soda, but this will generally yield a puffier, less crisp cookie. Use double-acting baking powder as your baking soda substitute for the best cookie results, since the single-acting variety may not have enough power to help the cookies rise properly. Replace baking soda with double-acting baking powder at a rate of 2 teaspoons of baking powder for every 1/2 teaspoon of baking soda.
If you're using potassium bicarbonate in place of baking soda, you don't really need to adjust the recipe, but the cookies may taste a bit bland because of the reduction in sodium. If this is the case, add up to 1 teaspoon of salt per 2 to 3 teaspoons of potassium bicarbonate to enhance the flavor. When using baking powder as a substitute, it's best to replace the acidic liquid in the recipe with non-acidic liquid. Double-acting baking powder has its first leavening reaction when it's exposed to liquids, and the acid in liquids such as buttermilk can stunt or halt that reaction and cause the cookies to fail to rise. Use a 1 to 1 ratio when replacing liquids, and try to substitute non-acidic liquids that have similar properties to the acidic liquids. For example, a good substitution for buttermilk would be regular whole milk. You also could replace citrus juice with water or milk, but make sure to add 1 to 2 teaspoons of grated citrus zest to the recipe to keep the flavor consistent.