Two types of cocoa powder are available to the home baker—Dutch-processed and natural—and I have long wondered if it really mattered which I used for what.
The first thing I learned in trying to answer this question is that natural cocoa tends to be a rather inconsistent commodity, varying in flavor, color, and intensity. In the mid-nineteenth century, a Dutch chocolate manufacturer came up with a process by which he could better control and standardize the color and flavor of cocoa. The process, which involves washing the cocoa (before or after grinding) in an alkaline solution, became known as Dutch-processing. The resulting cocoa is consistently darker in color, mellower in flavor, and less acidic than the natural (nonalkalized) powder. Some sources claim that it is also more soluble in liquid, but in my tests making hot cocoa and pudding, I didn’t notice much of a difference.
In tasting several brands of Dutch-processed cocoa along side a few natural cocoas, I did find that Dutch-processed cocoas are indeed less bitter than natural ones. When baking, however, any bitterness from natural cocoa is generally mitigated by the sugar, butter, and other good things. In cakes and brownies, the Dutch-processed cocoas tend to produce moister and deeper colored baked goods—an advantage that makes it a favorite of many pastry chefs.
In baking recipes, you’ll need to decide which cocoa to use based on the leavening the recipe calls for:
• Use natural cocoa—which has high acidity—in cakes made with baking soda; baking soda is an alkali and relies on an acid in the batter to produce leavening.
• Use Dutch-processed cocoa— which is much less acidic—in batters made with baking powder or eggs (or both), since these are leaveners that don’t depend on an acid in the batter to work.
Because of the importance of acidity and leavening, you may find some slight differences in the texture and height of your baked goods if you substitute one type of cocoa for another. In general, however, I found that only the recipes calling for 3/4-cup or more of cocoa powder were really affected.