Baking is very much a science and these ingredients are both chemical leaveners. Below is a summary of their main characteristics so that you will get to know them better.
Baking Soda- sodium bicarbonate
- when combined with an acidic ingredient (such as buttermilk, vinegar, lemon juice, chocolate that is not dutch-processed, sour cream, honey, molasses including brown sugar, yogurt etc), bubbles of carbon dioxide are formed that expand under heat, thus leavening the baked goods
- Reaction begins immediately when mixed, so the batter to be baked immediately, otherwise end product will be flat.
- Too much baking soda adds a "soapy" taste and it also causes cocoa to redden.
Baking soda can be kept almost indefinitely. They do not go bad but will lose their effectiveness. To test their effectiveness, mix 1/4 teaspoon of baking soda with 2 teaspoons of vinegar. The mixture should bubble immediately.
Baking Powder- contains sodium bicarbonate, and cream of tartar and starch
- comes in single-acting or double-acting
- single acting baking powder is activated immediately by moisture
- double acting baking powder is first activated by moisture, then by heat.
- due to its 2-stage leavening power, the batter or mixture can be delayed for about 15-20 minutes before the leavening power is lost.
TestTo test the effectiveness of baking powder, mix 1 teaspoon of baking powder with 1/2 cup (120ml) of hot water. The mixture should bubble immediately. Stick to the the expiry date on the label of the container. But if you have not used it for quite some time, even if it has not expired, do the simple test before you use it.
Baking soda can be substituted for baking powder in these proportions: 1 part baking soda, 1 part cornstarch, 2 parts cream of tartar. E.g. to substitute 1 tsp of baking powder, you can use 1/4 teaspoon of baking soda + 1/4 teaspoon cornstarch + 1/2 teaspoon cream of tartar.
But baking soda cannot be used to substitute baking powder.
NoteWhen adding either baking soda or baking powder, sift them and then whisk them with other dry ingredients so that they will be uniformly mixed in the mixture. Too much of them in one area will cause your baked good to have large holes.