(image courtesy of google images)
Sugar. Check. Flour. Check. Eggs. Check. Baking Soda – We have a problem.
I can’t tell you how many times I have underestimated my pantry stock (also reason #287 why you should have all your ingredients prepared before starting to cook or bake), and thus, have come to a fork in the road when I am missing a key ingredient. This is most especially crucial when it comes to baking, which comes down to basic chemistry in order to produce a successful result. But once question I have asked myself numerous times, and have been asked in return, is what is the difference between baking soda and baking powder, and can I substitute one for the other? The answer lies in science.
Baking soda is pure sodium bicarbonate. When baking soda is mixed with something acidic (such as buttermilk or yogurt) and moisture, a chemical reaction occurs in which bubbles of carbon dioxide form. Under the hot oven temperature, heat expands this process and this is what makes baked goods rise. Because this reaction occurs as soon as the ingredients are combined, recipes that call for baking soda must be baked immediately or they will fall flat.
Baking powder also contains sodium bicarbonate, but the acidifying agent, cream of tartar is already present. Two types of baking powder are available for baking use – single-acting baking powder and double-acting baking powder. Single-acting baking powder is activated by moisture, and therefore must be baked immediately after combining. Double-acting baking powder releases the carbon dioxide in two stages. The first, when the ingredients are combined at room temperature; and the second, when it reacts to the hot heat of the oven. Essentially, mixtures with double-acting baking powder can stand out longer before baking.
So when do you use baking powder or baking soda?
It all comes down to taste and ingredients. Baking soda has a bitter taste, and needs to counteract with an acidic ingredient like buttermilk or yogurt – this is especially found in cookie recipes. Baking powder on the other hand has both a base AND an acid, and in effect has a neutral taste – this works best with ingredients with neutral-taste (like milk) in recipes such as cake and biscuits. Because the ingredients directly affect the chemical reaction, it is possible to use baking powder when the recipe calls for baking soda, but it is not beneficial to use baking soda when it calls for baking powder because the recipe most likely lacks the acidifying ingredient. It is possible to make your own baking powder with baking soda by adding cream and tartar.