Tuesday, December 05, 2006
Baking Soda, Baking Powder, Cocoa and Chocolate
This post started off as my way of trying to explain the differences between cocoa powder and unsweetened chocolate. I started to wonder about this when I saw that many recipes called for both and I couldn't figure out why you would need powder when you have the 100% chocolate liquor of unsweetened chocolate. While researching this, I discovered that there were not one, but two types of cocoa powder available, natural and alkali (a.k.a. Dutch processed). The type of cocoa used appears important for baking not only because of the color differences in cake based on its pH (it seems that chocolate cake color is highly correlated with acidity level) but the choice of which type of cocoa powder you use affects whether you should use baking powder or baking soda. And then I realized I didn't know the difference between baking powder and baking soda. It was time to investigate the difference.
Turns out that baking soda is sodium bicarbonate, a base. When mixed with an acid (such as natural cocoa), carbon dioxide gas is produced, allowing your baked goods to rise. If there is no acid, there is no reaction. Also, once the reaction occurs, the gas is released and its over. This can happen if batter sits around or if the batter is over beaten.
Baking powder is a combination of baking soda and an acid. This allows it to provide its own rising power and makes baking powder less dependent on other ingredients. Double acting baking powders (and I've never seen any other kind in a supermarket) contain two kinds of acid: the first releases itself when liquid is added and the second when the batter is heated. The best source of all of this information is an ancient web post from 1998! Other sites tend to back up the information, and remember kids, Male Martha was a chemistry minor in college! This "built in acidity" explains why baking powder works better with Dutch process cocoa, which has been alkalanized.
Which brings us back to chocolate and cocoa. And since its getting late, they will have to wait. I will have more to say on both of them in the future.