I did a search and found lots of info, but I have a specific, kinda scientific, question regarding doing this that I could not find.

All of the chocolate cakes I've found have baking powder AND baking soda in them, while yellow cakes just have baking powder. When I looked up making marble, lots of people said to just either add cocoa powder or melted chocolate chips to some yellow batter and swirl it in. What about the baking soda? It must have something to do with the chocolate, no?

Can anyone explain the reasoning for baking soda in chocolate cakes? I'm really nervous about giving this a try (probably adding melted chocolate chips to yellow batter). Thanks!

Baking soda reacts with the oaxalic acid in the chocolate to increase leavening.

I was just searching some sites online. Here is some more information for you.

http://chowhound.chow.com/topics/387924


Just to expand on my earlier response, when recipes are formulated it's usually done in such a way that there isn't an excess of acid in the baked cake or bread. (Basic equilibrium reactions). So baking soda is used when a leavening agent such as baking powder or another acidic ingredient is used. Having said that if you use a cocoa powder that's dutched processed you will find you do not need to use the baking soda. The reason being is the cocoa has already been processed in such a way to raise the pH making it less acidic.

I hope this answers your question.

Yes, you guys did help, but I'm still not sure what to do because I was either going to use chocolate chips or cocoa powder that is not dutch processed, so I would still need to use baking soda according to the reasons above, but I haven't read that people are doing that when they add chocolate of this kind to their yellow cake batter. Argh. LOL! I'm going to have to just do it and hope for the best.

I made a marble cake with my scratch vanilla cake recipe. I took out about 1/3 of the batter and mixed in melted semi sweet chocolate and it turned out great.

I agree with Cake_Princess. I have had success just stirring in cocoa powder to a small amount of my yellow and white batters and then swirling it in to accomplish the marbled look. It is such a small percentage of your batter, that in the scheme of things, I don't think you need to get too hung up on the baking powder/baking soda issue.

Well even though at midnight when I was finishing baking I thought it was a total disaster (it appeared that the chocolate didn't rise as much as the yellow and that all of the chocolate got sucked into the middle of the pan somehow), but when I leveled off the cakes the next morning they were perfect! I even had enough batter to make some cupcakes. Would have had more, but I overfilled my pans to begin with.

You are right, it's probably such a small amount of batter that it doesn't matter. Thanks everyone! Oh, and I think I have a favorite cake flavor, marble!