KyleW is right. Natural cocoa treated with an alkali, usually potassium carbonate, is called Dutched cocoa. Natural cocoa has a sharp acidic fruitiness which, when treated, has a smoother milder flavor and it dissolves more easily. It also has a darker redder flavor. I use Dutched whenever possible, but I think if you only had natural, you could sneak a little baking soda into a formula and it will darken the cocoa.
So if making a chocolate cake with dutched cocoa, would you say less baking soda is used since the cocoa is already neutralized? How would you make the chocolate cake darker(blacker)when using dutch cocoa? I've always been confused by this issue.
I would think about scaling back, or even eliminating the baking powder, and maybe bumping up the baking soda a little. It may be heresy, at least Marcy Goldman says it is, but I find myself taking out the baking powder when a cake has a lot of honey, brown sugar, coffee, cocoa, or any other acidic ingredient. I was making honey cakes that absolutely frothed until I removed the baking powder. And the same with multiple sheet pans of devils food cake. The baking soda alone is enough to leaven. And it will turn the cocoa darker. It's not the same chemical normally used to dutch cocoa.
yes, it would be a very interesting experiment! I remember making a beet cake a couple months back and remember when the cake had baking powder and baking soda it was a deep brown color(sort of muddy color) and when I used all soda the cake came out more chocolatey dark, it really deepened in darkness, which was exactly what I was looking for. But the recipe used unsweetened chocolate and beets, both the acidic ingredients neutralizing the soda.