Baking soda in cookies serves several important functions:
- Leavening agent: Baking soda reacts with acidic ingredients (like brown sugar, buttermilk, or cocoa powder) to produce carbon dioxide gas, which helps the cookie dough rise and become lighter and softer. This reaction creates air bubbles that lighten the dough and contribute to a soft, chewy texture
- Encourages spreading: Baking soda raises the pH of the dough, which slows down protein coagulation. This delay means the dough takes longer to set in the oven, allowing melted butter and dissolved sugar more time to spread the cookie evenly before it firms up
- Enhances browning: By increasing alkalinity, baking soda speeds up the Maillard reaction-a chemical process between amino acids and sugars that causes browning and develops richer flavors. This results in cookies with a darker, golden-brown color and deeper taste
- Improves texture: Neutralizing charges on proteins in the dough means proteins require more energy and time to bond, leading to a slightly tighter protein network. This contributes to cookies that are chewier and firmer
- Flavor enhancement: Because baking soda contains sodium (salt), it subtly enhances the overall flavor of the cookies
In summary, baking soda is used in cookie recipes to create a chewy, dense, and thin cookie with good spread, a rich brown color, and enhanced flavor. It is especially important in recipes with acidic ingredients to achieve the desired texture and appearance
. Be cautious with the amount used, as too much baking soda can cause an off taste
