What is the difference between Baking Soda and Baking Powder?
Baking Powder and Baking Soda are both used to leaven dough. The difference between the two is simple, one has an acid and the other does not.
Baking soda is just Sodium and Bicarbonate, and best produces gas when combined with an acidic food, such as buttermilk. This is because the acid in the food separates the two molecules and allows carbon dioxide gas to be released (this comes form the bicarbonate).
Baking powder already has acid incorporated into the product, and is essentially ½ acid, ¼ baking soda, and ¼ cornstarch. Therefore, use baking powder in recipes not involving acidic ingredients because baking powder already has the acid.
The acid in baking powder helps to lessen the alkaline taste left behind from cooking with baking soda.