Baking soda and baking powder are easily confused because they have similar names and appearance. There are often added to the same recipe, but they are chemically different, so you should know the things that make them dissimilar. So here is the difference between baking soda and baking powder.
Baking Soda
This ingredient is also known as bicarbonate of soda or sodium bicarbonate. The baking soda is a base mineral, which, when combined with something acidic, produces carbon dioxide. Therefore, when a recipe needs baking soda, it actually needs some type of acid. When you use baking soda in a recipe, you also need something acidic, such as brown sugar, lemon juice, molasses, cream of tartar, yogurt, and buttermilk. So, they react together.
Baking soda is stronger than baking powder. However, too much baking soda doesn’t mean more lift and when it doesn’t react with any acid in the recipe there will be leftover baking soda in the recipe. Moreover, when it isn’t neutralized with acid, the recipe will have a metallic taste.
In order to decide the exact measurement of baking soda in a recipe, you should know the rule of thumb.
Baking Powder
Baking powder is a combination of various acids, including baking soda, cornstarch, and cream of tartar.
While cooking, the first leavening occurs when baking powder gets wet, and the next one when the baking powder is heated. The following rule is a great rule of thumb: add a teaspoon f baking powder per 1 cup of flour in a recipe.
Some recipes involve the use of both, baking powder and baking soda, and the reason for this is the maintenance of balance, as the carbon dioxide created from baking soda and certain acid does not leaven the volume.
Expiration date
You should note that they both have expiration dates, so you should use them fresh, and change them at least every three months.
Yet, you can also test their effectiveness before use:
If you want to test baking soda, pour 3 tablespoons of white distilled vinegar into a small bowl, add half a teaspoon of baking soda, and stir. The baking soda is fresh if the mixture quickly bubbles.
Source: chemistry.about.com ; simplyrecipes.com