This Is the Difference Between Baking Soda and Baking Powder
Here's when and why you would choose each of these pantry staples.
Their names are similar, they look alike, and they’re next to each other on the grocery store shelf, but baking soda and baking powder are not interchangeable. Like bread flour and all-purpose flour, these two pantry staples play similar roles in baking. They help cakes, pastries, and pancakes transform from flat, heavy, and tough to light, fluffy, and mouthwatering. But there’s a distinct difference between baking soda and baking powder.
Thanks to their unique chemical makeups, the ingredients achieve their result in slightly different ways. (Talk about a piece of food facts trivia most people don’t know!). Here, learn when you would use one over the other, why some recipes call for both, and how long these baking staples last.
What is baking soda?
Baking soda is a single-ingredient leavener used in baked goods. That ingredient? Sodium bicarbonate, which is ground into a fine powder to be used in recipes that require a quick rise, such as pancakes, muffins, and quick breads.
Because sodium bicarbonate is an alkaline compound, it causes baked goods to rise when combined with an acidic ingredient, like buttermilk, lemon juice, molasses, brown sugar, or cocoa powder.
It’s not just for baked goods though. Baking soda is one of the most versatile household ingredients, with uses ranging from natural cleaning, to nixing unpleasant odors, to soothing a sunburn.
What is baking powder?
The biggest difference between baking soda and baking powder is that baking powder contains sodium bicarbonate, plus two other ingredients: a powdered acid, such as cream of tartar, and a buffer, such as cornstarch.
While baking soda needs to be combined with an acidic ingredient for leavening power, baking powder doesn’t need to be combined with anything—it starts working as soon as it’s mixed with wet ingredients. When it’s activated at this step in your recipe, it’ll start to release tiny bubbles of carbon dioxide.
Baking powder is then activated further by the heat of the oven, which gives it twice the batter-aerating power. It’s how you get that light, fluffy texture you crave in your cakes and biscuits. It’s this self-sufficient nature that makes baking powder a more frequently-used and versatile leavener for your baked goods than baking soda.
Can I use baking soda in place of baking powder?
While baking soda is a component of baking powder, subbing in the former for the latter is not as simple as a one-to-one swap. According to baking expert Sarah Phillips, a key difference between baking soda and baking powder is the strength of baking soda. It’s roughly four times more powerful, so if you’re using one teaspoon of baking powder per cup of flour, you only need a quarter teaspoon of baking soda per cup of flour.
That said, the effects of an incorrect amount of baking soda are pretty noticeable. Too much creates a soapy, unpleasant flavor and an overly browned loaf, while too little will turn the flavor of your pastry from sweet and balanced to overly tangy.
If you’re out of baking powder, your best bet is to create a DIY version by mixing baking soda with an acid, such as vinegar, cream of tartar, or buttermilk.
Vinegar is the easiest option since you likely have it on hand and you won’t need to adjust any of the other ingredients in your recipe. To make one teaspoon of baking powder, simply mix a half teaspoon of vinegar with a quarter teaspoon of baking soda.
Can I use baking powder in place of baking soda?
Yes, you can still make cookies without baking soda. But you’ll need to take the strength of the two ingredients into consideration when making any swaps.
Because baking soda is much stronger, you need to replace it with four times that amount of baking powder. So if the recipe calls for a half teaspoon of baking soda, you’ll use two teaspoons of baking powder.
Why do some recipes use both?
The difference between baking soda and baking powder lies not only in their chemical makeup but also in how they impact your final product. Indeed, it’s the desired characteristics of your baked good—what it tastes, feels, and looks like—that determine whether or not a recipe calls for both leaveners.
Take buttermilk pancakes, for example. The recipe contains an acid (buttermilk), which typically signals that you would use baking soda as a leavener. But you want to taste the tangy buttermilk in your finished short stack. If you just use baking soda, it will neutralize all of the acid. Adding baking powder as well will give your pancakes the rise you’re looking for without compromising the buttermilk flavor.
On the other hand, baking soda also helps with browning. So if you used only baking powder and no baking soda in your pancakes, they would have those light nooks and crannies for soaking up syrup but no golden-brown finish.
When a recipe calls for both ingredients, it’s often because having both will deliver the perfect look, taste, and texture.
How can I tell if they’re fresh?
In general, baking soda will keep unopened for two years and opened for six months, while baking powder will last unopened for 18 months and opened for six months.
But if you’ve already passed those dates, there may still be hope! Since baking soda and baking powder are chemical leaveners, a little at-home science experiment will help you test whether they’ve expired.
Baking soda is activated by acid, so dropping a bit into some vinegar and watching for fizz will tell you if it’s still good. You can do the same with baking powder and hot water.