I’ve been baking since I was a kid and until today I never understood the difference between the two. In our house we have about a kg of Baking Soda, it is just so versatile we use it for cooking, cleaning, you can even make allergy free washing soda from it and mixed with vinegar in a drain works just as well as any chemical drain cleaner. In contrast we have a very very small container of baking powder that I have probably had for about five years now (I may need to replace it) but I just don’t use it very often.
Today/tonight has been stressful (unsettled, unhappy, unwell baby) and so once I had finally managed to get him to go to sleep in his own bed I decided I’d make myself a mug brownie except I noticed my normal recipe kinda falls a little flat so I decided to add a little baking powder which made me think is it baking powder or baking soda that makes stuff rise. Once again GOOGLE came in handy and I finally learnt something I probably should have known a long time ago and will prevent me from wasting my money buying Baking powder from now on.
Essentially Baking Powder and Baking Soda do the same thing, they make things rise by producing carbon dioxide gas. Here comes the chemistry (being a lab tech never stops). So from a chemistry point of view you are taking an Alkaline substance (baking soda) and mixing it into a mixture that is in some way acidic (probably something you added like sugar) when it is heated it speeds up the reaction and carbon dioxide is produced expanding the mixture and making your cake lovely and light and fluffy. The acid also neutralizes the by-product sodium carbonate which has a yuck metallic taste (hint: if you cake tastes metallic you have added too much baking soda for the amount of acid present).
Ok so Baking powder does exactly the same thing except you don’t need to have anything acidic in your mix because it is already built into the powder. That is right the powder is mixed so the right ratios of acid/alkaline are present and your cake will rise to perfection without the metallic taste. Baking powder is weaker than Baking soda, for 1sp of baking powder there is 1/4tsp of Baking soda. So don’t just go ahead and substitute because it won’t taste very good if you do.
You can make your own Baking Powder;
Mix 1 part baking soda to 2 parts cream of tartar, if you are wanting to store it mix in 1 part cornstarch and place in a dry jar or container.
Seems pretty easy right and most bakers/homesteaders/chefs would have these ingredients sitting in the back of their pantry. No more mad dash to buy Baking Powder or cakes tasting like metal. One thing to be careful of is that natural cocoa is acidic so will take a little more to rise then processed alkalized cocoa, so if you cakes are falling flat maybe take a look at your cocoa it could be the cause.
If you want to learn more just google or follow the links I found: