Here's how it works:
1. Reaction with acid: Baking soda is a base. When mixed with an acidic ingredient like buttermilk, lemon juice, or even cocoa powder, it undergoes a chemical reaction.
2. Carbon dioxide production: This reaction produces carbon dioxide gas. The tiny bubbles of carbon dioxide gas become trapped in the batter.
3. Rising batter: As the batter heats up during baking, the trapped gas expands, causing the batter to rise.
Why baking powder is better than just baking soda:
While baking soda alone can work as a leavening agent, it needs an acidic ingredient to activate. Baking powder contains baking soda, an acid (like cream of tartar), and a drying agent (like cornstarch). This means that baking powder is a self-acting leavening agent, requiring no additional acidic ingredient.
In summary: Sodium bicarbonate (baking soda) is used in baking powder because it reacts with acids to produce carbon dioxide gas, which causes the batter to rise and create a light texture. Baking powder is a more convenient option than baking soda alone as it contains both the base and the acid required for this reaction.
