Article by: Cece Kirkwood. This article may contain affiliate links.
Here is a question I’ve avoided for too long as a self-taught baker… what is the difference between baking powder and baking soda? Why, when I read a new recipe, do I double and triple check which one the recipe calls for and then check AGAIN to make sure I grabbed the right one?
I knew there was a difference. I knew it would affect my baking. But I did not know why.
For the same reasons why I firmly believe baking should be done by measuring ingredients by weight, not volume, I realized I just could not go any longer without knowing the difference between these two seemingly similar rising agents.
So, down the rabbit hole I went into baking science so you don’t have to. Read on my friend and never wonder again, why do these two ingredients look so similar and yet are so vastly different?
The Science Behind Baking Soda and Baking Powder.
So what exactly makes a cake rise? Sure you add a rising agent, but what actually happens? The answer is simple, in the oven your ingredients will work together to produce carbon dioxide, aka CO2.
Before we get too scientific, let’s break this down. CO2 is the same gas you and I exhale after we breathe in oxygen. Those exhaled breaths can be used to “blow things up” like balloons at your childhood birthday parties. A similar reaction happens in childhood science experiments with volcanoes. You add ingredients to a mixture, shake things up and BOOM! Bubbles. Growth. Explosion. That same quick reaction happens on a smaller scale in the oven, thanks to rising agents like baking soda and baking powder.
But how do you know when to use one or the other?
What is Baking Soda?
Take out a box of baking soda and you’ll see one ingredient – sodium bicarbonate. That is because baking soda is pure sodium bicarbonate. Nothing else. Sodium bicarbonate is a leavener on its own, but it needs to be activated by an acid in order to produce CO2, the gas that is needed to lift our favorite baked goods while in the oven. Therefore you use baking soda in recipes that call for an acid like brown sugar, buttermilk, yogurt or fruit juices.
What is Baking Powder?
When your recipe does not call for an acid agent to activate the baking soda, you’ll pull out the baking powder from the cabinet.
Baking powder is sodium bicarbonate (baking soda) + a powdered acid (usually cream of tartar). It already contains the acid needed to activate the rise in the oven. So in the simplest terms, you would use baking powder when your recipe does not call for an acidic ingredient.
But things get a little complicated if, like me, you’ve experienced the phenomenon of tasting an extremely bitter taste on your tongue when eating baked goods that contain baking powder. It is totally normal, but incredibly frustrating.
Why does Baking Powder cause a bitter taste?
Most of the time, this is caused by using too much baking powder in a recipe or not enough flour or perhaps you didn’t sift your ingredients together. It can also be caused by expired baking powder.
BUT, if you are the sensitive type like me – you can do everything “right” while baking and still the bitter taste arrives.
After a lot of googling, mostly by my husband, we discovered that there are two different types of baking powder.
WAIT WHAT?! Not only do I need to worry about baking powder vs. baking soda, but now there are two types of baking powders? I know, I know. It can be a lot and if you don’t experience that bitter taste, this is probably not something you need to worry about, but if you do…
The Two Types of Baking Powder
Single-Acting Baking Powder
Single-acting baking powder creates the CO2 immediately when mixed in with all the other baking ingredients. For this reason, the baked goods need to be added to the oven rather quickly. It acts once.
Double-Acting Baking Powder
Double-acting baking powder, as the name implies, acts twice. The first is soon after it hits your mixing bowl and the second is once it enters the oven and hits a certain temperature. So you can have a bit more time to mix and take photos and make sure everything is just right. The ingredient that makes this happen is called sodium aluminum sulfate. That ingredient right there – that is the one that can create those bursts of bitterness on your tongue when you bite into baked goods.
So if you’re like me, you suffer from the random bitter bites, skip the aluminum and go for the single-acting baking powder. You’ll need to move a bit faster in the kitchen, but we aren’t talking the speed of light. Just don’t get distracted by social media while baking and you’ll be just fine.
Why do some recipes call for both Baking Powder and Baking Soda?
You’ll come across recipes that will call for both baking powder and baking soda – it is more common than you would think.
Sometimes, whatever acidic ingredient you are adding to the batter or dough is not enough to activate the baking soda. So, the recipe will call for the baking powder to pop in and do its job to create that rise in the oven.
Baking soda also helps baked goods brown better.
Can I substitute one for the other?
The short answer is no. You really should not replace one for the other. There are conversions that people have tried to figure out, but honestly, I do not want to mention them because it will change the taste, texture and rise of your recipe. So it is best to just run out to the store if you realize you need one that you do not have.
Okay, anything else?
Remember that just like other foods, these do expire! You can check the label on each of the products or run a little science experiment of your own in the kitchen that I learned from Sally’s Baking Recipes.
For baking soda, Add a few tablespoons of vinegar to a glass and ½ tsp of baking soda. Give it a little stir and if things begin to fizz then you are ready to bake!
For baking powder, add a few tablespoons of water to a glass and combine it with ½ tsp of baking soda. After a little stir, you should start seeing bubbly, fizzy action. If not, it’s time for new baking powder.
And finally, remember that baking is a science. Being exact matters. Chemical reactions happen in the oven, so knowing how and why your ingredients are acting the way they do… matters.
Interested in more baking basics? Don’t worry, I’ve got you covered.
Now, bake on my friendly scientific baker and feel a bit smarter than you did before.
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