It’s no wonder that baking soda and baking powder are easily confused, considering their similar names and appearance, plus the fact that they’re often used within the same recipe. But when it comes to their individual uses, it’s important to know the difference—lest you wind up with a minor baking disaster on your hands.
So let’s break it down:
According to Susan Reid, chef and food editor of Sift magazine, baking soda is a base mineral, which, when combined with something acidic, produces carbon dioxide. “Usually this happens in liquid, and the results you get are bubbles,” says Reid. “Think of the volcanoes you see at every 5th grade science fair. Those bubbles can lift stains or act as a surfactant (meaning they will clean things).”
In other words: baking soda can do some pretty magical things.
Typically, you’ll see the ingredient pop up in baking recipes that also include acidic ingredients like molasses, maple syrup, lemon juice, and pumpkin. The reason it’s there is to act as a leavener, to help the dough rise. “Recipes using baking soda often bake up darker, and are more crisp, than those without,” adds Reid. But be warned, “too much baking soda in a recipe can give it a bitter, soapy taste.”
When it comes to cleaning, you can use baking soda for pretty much anything you can imagine, from unclogging drains to deodorizing the carpet. It’s even been used to remove heel marks from linoleum floors.
As for what it’s made of? That may surprise you: Baking soda is basically ground up rock, according to Reid, and as long as it stays cool and dry, it lasts indefinitely. (Hence why your mom’s had the same box of it in her pantry since what seems like 1975.)
Baking powder on the other hand, is actually a combination of baking soda plus another acid, in the presence of an inert stabilizer (a fancy term for an inactive ingredient that keeps the mixture from reacting), which is often a bit of cornstarch. What that means: Everything stays inert in the mixture until liquid is added, which allows the soda and acid to combine to produce carbon dioxide (which look like bubbles to the naked eye). This process is what gives baking powder its lifting power in recipes—without which, you’d have some sad-looking biscuits on your hands.
But just like baking soda, Reid says baking powder can lose its lifting power over time if it’s not stored in a cool dry place. If you can, keep it free from humid conditions, since extra moisture in the air can allow the reaction between acid and base to happen.
Pay close attention to the label when you buy a new box, since there are actually two different kinds of baking powders out there: single-acting and double-acting. Single-acting powders react fully when you combine them with another liquid. But double acting baking powders work in two stages: Once when combined with a liquid, and again when combined with heat. “Since the balance of the base (soda) and acid is calculated for you, it’s easier to get a final product that has no aftertaste when used in proper amounts,” says Reid.
Still not sure you’ll remember the difference between these two ingredients? Reid has a quick trick: Think baking soda = single ingredient. Baking powder = poof in the oven.