Baking Soda vs. Baking Powder: What's the Difference?

Baking soda is made of sodium bicarbonate. 

When an acid is combined with sodium bicarbonate, it reacts and results in the formation of CO2 bubbles that resemble liquid foam. This process is called chemical leavening, allowing baked goods to rise. 

Most recipes that call for the use of baking soda will also list an ingredient that contains acid, such as buttermilk, yogurt, or vinegar.

Baking powder, on the other hand, contains both sodium bicarbonate and acids.

One of the acids is monocalcium phosphate. As soon as baking powder is added to a wet batter or dough, the monocalcium phosphate reacts with the sodium bicarbonate, producing CO2 bubbles and resulting in chemical leavening.

To prolong the chemical leavening process, baking powder includes a second acid, either sodium acid pyrophosphate or sodium aluminum sulfate. Both acids must be wet (mixed into the batter) and heated before they begin to react with sodium bicarbonate. This makes the batter rise for a longer period, resulting in more bubbles and therefore a fluffier result.

Baking soda and baking powder can be interchanged in recipes, but it may affect the texture and flavor of the final product.

Baking soda requires an acidic substance in order to activate, whereas baking powder requires a watery liquid.

Substituting baking powder for baking soda

While baking powder can be used in place of baking soda, you cannot use the same quantity. Because baking powder is not made entirely of sodium bicarbonate, you may need to use 3-4 times as much baking powder to achieve the desired rising.

Because you will have to use much more baking powder in place of baking soda, it can cause your final product to have a slightly bitter or chemical taste.

Substituting baking soda for baking powder

Because baking soda is stronger than baking powder, you only need a small amount—about 3-4 times less—if you are replacing baking powder in a recipe.

Baking soda also requires an acidic component, which the original recipe may not have included. One approach is to add yogurt, lemon juice, or vinegar to activate the baking soda.