Reader Question: Hi H! Technical question: how come some of your recent cookies don’t have baking powder or baking soda? These are ingredients I almost always find in cookies. Cookies don’t really “rise”, but what do these ingredients do? Or, written another way, what would happen if I made this recipe and added one or the other one in?
Baking soda is sodium bicarbonate. It is a base. When added together with an acid, it creates a reaction and the byproduct is carbon dioxide. Maybe you remember from when you were a kid and mixed baking soda and vinegar together to make volcanos. Same idea. Consequently, you want to add baking soda to baked goods where there in another acidic ingredient. Buttermilk, lemon juice, and some cocoa powders are all examples of acidic ingredients.
One of the reasons that baking soda is regularly used in cookies is that it makes your baked goods spread so you get a flatter, crispier cookie.
Sodium bicarbonate plus cream of tarter. What is cream of tarter? It is potassium bitartrate and is an acidic byproduct of winemaking. It is added to the sodium bicarbonate (aka baking soda) in order to activate it. That way you do not have to have any acidic ingredients in the recipe, you can use regular milk and flour, etc. Baking powder makes your baked goods puff up, which is once of the reasons it is used in many cake recipes.
Can you swap one for the other?
Not really. Even though baking powder is comprised to baking soda, you would have to add in a lot more baking powder to get the same effect. I mixed the two up when baking stout cake once and had a big flat mess on my hands.
The other part of the question was why have some of my cookie recipes not called for either one? Well, in the case of the caramel apple cookies-butter makes the cookies spread quite a bit already and the eggs in the batter provide enough puff. Also any of the cake mix cookies will already have one or the other in the mix so no additional is needed.
Personally, I have always wondered why some recipes, like butternut squash bread, required both. Looks like the answer to that is you may may have a bit of acid in the recipe but not enough to make the product raise on just baking soda alone. So you use baking soda to neutralize the acid and baking powder to puff up the baked good.