Baking Powder vs. Baking Soda

When it comes to baking, it’s important to understand the basics! Today we are nerding out and diving into two ingredients that usually get confused for each other – baking powder vs. baking soda. So let’s finally understand the difference and how they work in baking.

I think when it comes to baking, one of the questions I always get asked is what’s the difference between baking powder and baking soda? I’ll admit I’ve mixed them up a few times myself. Tired me = should not be baking.

And if you have ever mixed them up then you might have realized very quickly they are SO. Not. The. Same. Oh well. Lesson learned the hard way. But I believe if you want to become a better baker, then you need to make sure to 

a) not mess those two up

b) understand why they are different. 

So that’s what we are doing today. We are going to nerd out on some baking science today. So you with me? 

What’s the difference between baking powder and baking soda? 

Before we talk differences let’s talk similarities. Both are leavening agents. This means that these ingredients are responsible for causing your baked goods to rise. 

But chemically they are fundamentally different. 

What is baking soda? 

Baking soda (also known as bicarbonate of soda or sodium bicarbonate) is a base. Yes we are going to have to channel our science class days on this one. If you had a childhood like mine that you reacted baking soda and vinegar to watch a fun volcano happen. Well that is what is happening when add a baking soda to your cookies. 

Baking soda is added to a recipe to react with the acidic ingredients in your recipe. And when they come together they create those lovely bubbles (aka carbon dioxide) which help to make your baked goods rise. So if you see a recipe calling for baking soda. Look again. Because you will probably see an acidic ingredient there to balance it out like in my red velvet cake recipe, such as:

• Buttermilk
• Chocolate
• Lemon juice
• Vinegar
• Yogurt
• Molasses

Pro Tip: For 1 cup of flour in a recipe, use about 1/4 teaspoon baking soda to leaven.

What is baking powder?

Baking powder on the other hand is actually baking soda + a dry acid (like cream of tartar). They are usually mixed with a bit of cornstarch, to help keep them separate and dry. 

You will notice that most baking powders are labeled, as “double acting”. This means it will react twice, causing two sets of bubbles to occur. Double acting baking powder will react first when it encounters a liquid, like when you add it to your batter, and then again with heat from the oven. 

Baking powder is most often used when an acidic ingredient is not used because it already contains an acid to neutralize the baking soda in it. Plus, because you get that second lift you get a little flexibility of letting that batter rest a bit before popping it in the oven. 

Pro Tip: For every cup of flour, use 1 teaspoon baking powder to leaven.

Why do some recipes call for both baking soda and baking powder?

Ever notice how some recipes will use BOTH baking soda and baking powder? If a recipe calls for an acidic ingredient, the baking soda will react and give off some carbon dioxide to provide some lift. However, it does not provide enough to completely leaven the baked good. 

So the recipe will also use baking powder to provide that second lift like in my sour cream lemon pound cake recipe. 

Be sure to test for freshness!

Your baking soda and baking powder are chemicals which means they have a shelf life to how long they can react. If you have ever had a baked good fall flat and not rise. Your old baking powder and baking soda may be to blame. Now according to Spruce Eats, an unopened package will last 2 years, whereas an opened package lasts 6 months. 

So if you’re not sure how long it’s been sitting in your cupboard it’s time to test for freshness. 

To test for baking powder: Add a 1/2 teaspoon to about 1/4 cup of hot water. If it bubbles, then it’s still good to use. If it doesn’t then time to throw it out and buy new!

To test for baking soda: Add a 1/2 teaspoon to about 1/4 cup of an acid (such as lemon juice or vinegar). If it bubbles, then it’s still good to use. If it doesn’t then time to throw it out and buy new!

What happens if I use baking soda instead of baking powder? 

Baking soda can leaven a baked good when exposed to heat, but if it’s not neutralized with an acidic ingredient your baked good will most likely have a metallic after taste. 

What can I use if I don’t have baking powder?

If you don’t have baking powder, you can always substitute baking soda and cream of tartar. You can’t just do a 1:1 substitution with baking powder vs baking soda. If you need two teaspoons of baking powder, you can use 1 teaspoon of cream of tartar with 1/2 teaspoon of baking soda. 

What can I use if I don’t have baking soda? 

If you have run out of baking soda, you can use baking powder, but you will need a bit more of it. Here is what to do:

For 1 teaspoon of baking soda called for in a recipe you would substitute with 3 teaspoons of baking powder.

So have we sufficiently nerded out for today?

For more baking 101 posts give these a read:

• My Top 10 Baking Tips
• Natural Cocoa vs. Dutch Process
• What are the different kinds of yeast?
• What flour is best for cookies?
• Types of Flour – Ultimate Guide