What is the purpose of baking soda in a cake?

Baking soda plays a crucial role in cakes, acting as a chemical leavening agent. Here's how it works:

* Reaction with Acid: Baking soda (sodium bicarbonate) is alkaline. When combined with an acidic ingredient (like buttermilk, lemon juice, or brown sugar), it undergoes a chemical reaction that releases carbon dioxide gas.

* Expansion & Lightness: This carbon dioxide gas gets trapped within the batter, creating tiny bubbles that cause the cake to rise and become light and airy.

* Tenderness: The bubbles also create a more tender crumb structure, preventing the cake from becoming dense and chewy.

Important Note: Baking soda requires an acidic ingredient to activate its leavening properties. If your recipe doesn't contain an acid, baking soda alone won't work.

In summary, baking soda is essential for:

* Rising and lightness: The carbon dioxide gas creates bubbles for volume.

* Tenderness: The bubbles create a delicate crumb.

Without baking soda, your cake would be flat, dense, and likely tough.