Both baking soda and baking powder, referred to as chemical leaveners, give breads, cakes, and other doughs and batters a light texture by introducing carbon dioxide gas into the batter. The gas expands the bubbles that are already present in the batter due to the action of mixing or creaming. Once the baked good goes into the oven, the heat causes the gas to expand so that the bread rises even higher. Eventually, the other ingredients of the batter settle into a firm structure. These little pockets of empty space cause the baked item to crumble or break apart easily when we eat it.
Baking soda, also known as bicarbonate of soda, needs to come into contact with both a liquid and an acid in order to work. Batters that include buttermilk, yogurt, sour cream, or fruits often call for baking soda. Bakers used to add cream of tartar to react with the baking soda if the recipe didn’t use acidic ingredients, a trick that is reflected in older recipes.
Baking soda reacts immediately when it is moistened in the presence of an acid, and recipes leavened by baking soda alone should be baked soon after mixing to take full advantage of the leavening power.
Baking powder is a mixture of an alkali and an acid, plus cornstarch to keep the powder dry until use. Baking powder begins working when it comes into contact with a liquid, and it receives another boost when it goes into the heat of the oven. This double reaction is why it’s referred to as “double acting.”
When chemical leaveners aren’t fully blended into the batter, they clump together. Biting into a pocket of baking powder leaves a bitter or soapy taste in your mouth. Combine the baking soda or powder completely with the flour by sifting, stirring, or whisking together the dry ingredients before mixing in the remaining ingredients.
Baking soda keeps for up to 2 years if it is stored in a cool, dry place, but it does gradually lose its effectiveness. To test it, mix about 1/4 teaspoon with 2 teaspoons of vinegar. It should foam up immediately.
Baking powder lasts about 6 months. Check it by mixing 1 teaspoon baking powder with 1 cup hot water. If it bubbles immediately, it is still potent enough to leaven a batter.
Fascinating, what else does cream of tarter do?
It’s really versatile! We also add a pinch of cream of tartar to egg whites to help stabilize a meringue or an angel food cake, and a pinch in a cooked sugar solution can keep the mixture from crystalizing. Some people add it to water before blanching, poaching, or steaming vegetables, since the acid lowers the pH of the water and can help keep the veggies vibrant and colorful.
What is the purpose of adding both baking soda and baking powder to a recipe?
If a recipe calls for baking soda and baking powder, it’s generally there to add a little extra oomph. Baking soda + an acid, like yogurt or buttermilk, may not be quite enough to lift certain batters. Since baking soda needs acid, adding more baking soda would require the addition of more acid, which may not be ideal for the finished product. So instead, we add a little baking powder, since it brings its own acid to the party. Both may also be used as a way to balance the pH of a dish, either to add a more acidic flavor or to help promote browning.
Thank you so much! So informative and interesting!
But it’s interesting that most recipes for chocolate chip cookies call for baking soda only and I don’t know what would represent an acid in a chocolate chip cookie recipe.
Love this culinary science chit chat! Brown sugar, which contains molasses, is actually an acidic ingredient! That’s why the best chocolate chip cookie recipes contain brown sugar. You CAN make a cookie with granulated sugar and baking soda, but you’ll notice that it’s much more dense.