"Each thing you bake is a mini science experiment," explained Kathy Walsten, nutrition educator with Kansas State University Research and Extension.
Often, it's the same experiment that students see when a teacher mixes baking soda with vinegar or lemon juice. The outcome is a fizzing chemical reaction - the release of carbon dioxide (CO2) bubbles.
When used in recipes, baking soda and baking powder both fizz when mixed with liquid and an acid, Walsten said. That's why they're called leavening agents. Their CO2 bubbles are what make cakes, muffins and quick breads rise.
Baking soda is the leavening agent in recipes that have an acid-containing liquid ingredient, such as buttermilk or yogurt. Baking power is soda that comes with its own dry acid, so, it's the leavening agent when a recipe's other ingredients just offer moisture.
That's why cooks shouldn't ignore the part where recipe instructions call for mixing all the dry and liquid ingredients separately, Walsten said. The approach means two bowls to wash. But, it also ensures the leavening reaction won't start until the very end of the mixing process.
Recipes also are controlling the reaction when they instruct cooks to mix the ingredients until barely moistened. This approach creates a lumpy batter that concerns some cooks, Walsten said. It also minimizes the amount of CO2 gas that can escape from batter.