The Science of Baking
Part 1: the purpose of baking soda
Have you ever wondered why you put baking soda in your dough/batter, or baking powder, or sometimes BOTH? What's their purpose? And why did I have to add VINEGAR to my delicious red velvet cupcakes? Weird, huh?
The purpose of Baking Soda and Baking Powder: these substances are leavening agents, which means they help batter rise quickly while baking. They do this by emitting carbon dioxide, which adds volume and lightness to the texture of cakes/cookies, etc. Baking soda is usually combined with an acid (for ex: sour cream, buttermilk, honey, brown sugar, and even vinegar!) which actually results in the carbon dioxide. This allows the batter to rise more quickly and to sometimes add flavor.
The difference between Baking Soda and Baking Powder: so now you've learned you need to add an acid. Baking powder is a mixture of baking soda and an exact amount of acid (usually cream of tartar), so that step is taken care of for you. So baking soda and baking powder are NOT interchangeable! Sometimes recipes call for both to produce a particular type of result.
So why vinegar? Some of you may remember combining baking soda and vinegar in your grade school days. Remember what happens? It creates bubbles so quickly that often the combination is used to create rockets. So when I saw this combination in my recipe, I was stunned. Really? But I trusted Martha... Vinegar was actually used in combination with baking soda back during WWII during the rationing of eggs. This combination can be used as a substitute for eggs if you're ever out of them or if you are vegan. The reaction is fun to see, and once combined and added to your batter should be used right away so you don't lose all that fluffy gas in your batter. And don't worry, your batter will NOT taste like vinegar at all! Trust me, I tried a number of these cupcakes to make sure... :)
Recipe (from Martha Stewart's Cupcakes):
2-1/2 Cup cake flour, sifted
2 Tbsp unsweetened cocoa powder
1 tsp salt
1-1/2 Cup sugar
1-1/2 Cup vegetable oil
2 large eggs at room temperature
1/2 tsp red gel-paste food color
1 tsp vanilla extract
1 Cup buttermilk
1-1/2 tsp baking soda
2 tsp distilled white vinegar
Cream cheese frosting
1. Preheat oven to 350. Line muffin tins with paper liners. Whisk together cake flour, cocoa, and salt, set aside.
2. With an electric mixer on med-high, whisk sugar and oil until combined. Add eggs, one at a time, beating until each is incorporated, scraping down sides of bowl as needed. Mix in food color and vanilla.
3. Reduce speed to low. Add flour mixture in three batches, alternating with two additions of buttermilk, and whisking well after each. Stir together the baking soda and vinegar in a small bowl (it will foam); add mixture to the batter, and mix on medium speed 10 seconds.
4. Divide batter evenly among lined cups, filling each 3/4 full. Bake rotating tins halfway though, until a cake tester inserted in centers comes out clean, about 20 minutes (10-12 min for mini cupcakes). Transfer tins to wire racks to cool completely before removing cupcakes. Cupcakes can be stored overnight at room temp, or frozen up to 2 months in airtight containers.
5. To finish, frost cupcakes with cream cheese frosting. Recipe: With an electric mixer on med-high speed, beat 1 cup unsalted butter at room temp. and 12 oz. cream cheese at room temp until fluffy, 2-3 minutes. Reduce speed to low. Add 1 lb. (4 cups) confectioners' sugar, 1/2 cup at a time. Then add 3/4 tsp vanilla and mix until smooth and combined, scraping sides of bowl as needed. Refrigerate up to 3 days in airtight containers.
Oh, and they make a nice Christmas bake sale item! Hope you enjoyed your science lesson for today!