Baking soda, scientifically known as sodium bicarbonate, primarily acts as a leavening agent in baking. When combined with an acidic ingredient and a liquid, it produces carbon dioxide gas, which forms bubbles that cause the dough or batter to rise and become light and fluffy

. This chemical reaction is immediate upon contact with acid, so recipes using baking soda require an acidic component such as buttermilk, lemon juice, yogurt, vinegar, brown sugar, or natural cocoa powder to activate it

. Besides leavening, baking soda also affects the texture and color of baked goods. It raises the pH of the batter, creating a more alkaline environment that speeds up browning through the Maillard reaction between sugars and amino acids, resulting in a desirable golden-brown color and enhanced flavor

. This is why baking soda is often used in recipes like cookies, banana bread, and soft pretzels to improve browning and develop a tender crumb

. However, the amount of baking soda must be carefully balanced with the acid in the recipe. Too much baking soda without enough acid can leave a metallic or soapy aftertaste

. Additionally, baking soda can contribute a slight salty flavor and improve the crumb texture by tenderizing the baked goods

. In summary, baking soda in baking:

• Acts as a leavening agent by producing carbon dioxide when reacting with acid, causing rise and lightness.
• Raises pH to promote browning and flavor development.
• Improves texture by tenderizing and creating a finer crumb.
• Adds a slight salty flavor in some recipes.
• Requires an acidic ingredient to activate properly and avoid off-flavors.

This makes baking soda essential for "quick" breads, cookies, cakes, and other baked goods that rely on chemical leavening rather than yeast