That moment when you realize that you only have one ingredient missing from what looks to be a stellar recipe can ruin your entire day. With a busy schedule, its often hard to put everything on hold to quest out to find the missing link. However, if that one ingredient missing from your favorite oatmeal cookie recipe happens to be baking soda, there is a quick and easy alternative that does not require a trip to the local grocery store -- baking powder. With a few simple considerations, one can easily be swapped for another.
The reason why both baking powder and baking soda are used in a variety of recipes is their quick leavening properties. Baking soda, or sodium bicarbonate, combines with an acid within a recipe, such as lemon juice, to create carbon dioxide which forms bubbles within the batter, causing it to rise. Baking powder works much in the same way as soda, as it actually contains sodium bicarbonate, but also an acid as well, which makes it perfect for recipes where an acid is not added to the batter.
Due to baking powder containing a certain portion of baking soda, with additional starch and acids, there is a need to use more powder than the amount of soda called for in an oat cookie recipe. Substitute baking powder in a ratio of 3 parts to every 1 part of baking soda called for in a recipe. Use it in the same step that you would for the soda, generally whisking it into the dry ingredients, such as the flour and oats, before wet ingredients are added to make a batter.
Because you need to use more baking powder in lieu of soda, the resulting taste may be different from the one desired. To combat this, when substituting baking powder for baking soda in oat cookies, add a touch more vanilla, or desired spices, such as cinnamon, to create not only a more flavorful cookie, but to combat the change in flavor that may result from substituting baking powder for baking soda.
If your cookies and cakes that call for baking powder continually come out flat, check the container housing the ingredient. If air comes into contact with the powder over a long period of time, it causes the reaction to occur within the container, and not work during the baking process itself. Always use by the "best before" date as well, or else the reaction won't work or will be minimal after this time.