What's the difference between cocoa powder and Dutch processed cocoa?
Regular or nonalkalized cocoa is lighter in colour and sharper in flavour. It is acidic, so when added to recipes with an alkaline ingredient like baking soda, the two react and leaven a product.
Dutch processed cocoa is alkalized and is less acidic, darker and more mellow in flavour. It won't react properly in recipes calling for baking soda and if used, the product may taste soapy. I prefer it in recipes that don't call for baking soda for the main leavening agent.