I'm experimenting with brownie recipes, and I wanted to consult a canonical one to see what people generally prefer. Reading the ingredients, they use natural cocoa, dutch-processed cocoa, and baking soda:
sugar, enriched bleached flour (wheat flour, niacin, reduced iron, thiamin mononitrate, riboflavin, folic acid), semi-sweet chocolate chips (sugar, unsweetened chocolate, cocoa butter, whole milk powder, soy lecithin [emulsifier], vanilla extract), cocoa, soybean oil, cocoa (processed with alkali), bittersweet chocolate chips (unsweetened chocolate, sugar, cocoa butter, soy lecithin [emulsifier], vanilla extract), salt, artificial flavor, baking soda
Why would you use both natural and dutch? Is the baking soda to neutralize the acidity in the natural cocoa, is it a leavening agent, or both? I know some brownies are slightly leavened. If it's just to neutralize the acidity, why use natural cocoa at all, or could it still act to balance the dutch processed cocoa flavor?