You know this story well: you’re in the kitchen baking, and the recipe calls for some baking powder, so you reach into your pantry and grab some. Right before you go to pour it into the mixing bowl, you stop yourself and breathe a sigh of relief— you grabbed the baking soda by mistake, but caught yourself in time. Still, you wonder, “What really would have happened?”

Or how about this: your fridge is smelling not-so-great, and you want to freshen it up. You know that baking soda is the go-to answer, but you’re all out. You do have baking powder, except that won’t work the same way— but why?

Or, what about when a recipe calls for both baking soda and baking powder, and you spend the whole time checking and double-checking that you’re not mixing up the amounts and when they need to be mixed into the batter? How bad would it really be if you got the two switched? What is the real difference between the two?

That’s what we’re going to learn today. Here’s everything every baker should know about the difference between baking powder and baking soda.

Baking Soda

You know that baking soda plays a part not only in our baking, but in our cleaning, our crafts, our home remedies, and all other sorts of DIY reasons. Why is it so versatile? Well, see if you remember this fun fact from science class: baking soda is a chemical compound officially called sodium bicarbonate, and also sometimes known as bicarbonate soda. It’s about as basic an ingredient as things can get— and we mean that it both senses of the word. Baking soda is not only basic in the sense of being an essential, foundational item, but because it’s the opposite of acidic; it has a pH level higher than something like, say, vinegar.

We can feel those of you who hated science class nodding off, but stay with us! So, we know baking soda is basic, so what happens when it reacts with something acidic— something in a recipe like vinegar, or buttermilk, or lemon juice, or brown sugar? The two react and create carbon dioxide, usually noticeable in the form of bubbles.

That’s right— at its baking-related heart, baking soda is a leavening agent. We need it to create air and create rise, and you do that by combining it with another, acidic ingredient that will react with it. Baking soda will also create this effect on its own when you heat it, but the result is a metallic taste associated with basic pH levels. So the acid not only helps with the reaction, it also balances out the taste so you get the air bubbles without the problems.

Also, guys, that box you keep in your fridge to absorb smells? Don’t bake with it. You don’t want those leftover scents transferred to your cookies and cakes!

Basic.

Baking Powder

OK, so where does this information leave baking powder? Savvy bakers have probably noticed that baking powder has baking soda in it. Other things it has? Cream of tartar and, on occasion, cornstarch. Notice anything about those extra ingredients? That’s right, they’re acidic— so that reaction we talked about above? It’s built right into the powder. Baking powder most often makes an appearance when there aren’t any other acidic ingredients in your dish, because you need that built-in acid to create the carbon dioxide and balance the taste.

Additionally, most baking powders now have what’s called a “double-leavening effect.” You get one air-building reaction when the dry and wet ingredients are mixed together, and another when the heat hits. If you’re using baking powder, you can’t make your batter ahead of time, because that first leavening reaction starts as soon as the ingredients come together.

It all comes down to that balance of acidic and basic, and the leavening effect. Whether you use soda or powder, how much you use, and what else goes into the recipe is all about how much “tang” you want to taste, and how much air you need. Bakers will use one or both in different amounts to achieve the different effects.

It’s chemistry. So experiment!

What It All Means For You

“OK,” we can hear some of you saying. “This little chemistry lesson was great and all, but I’m a home baker, not a professional or a chemist. What am I supposed to take away from all of this info?” So here’s the real world application you need to know.

Can I use the two interchangeably?

The short answer? Not really. Like we discussed above, there’s an extra element in baking powder, whereas baking soda is just baking soda. They do similar leavening things in the recipe, but when it happens is different – when dry and wet ingredients come together plus when the heat hits, versus just when the heat hits – and, perhaps more importantly, they’ll taste a little different, too.

Longer answer? It’s possible if you’re smart about it . . .

If you need baking soda but only have baking powder:

The rough answer is to use about 2 to 3 teaspoons of baking powder for every teaspoon of baking soda called for. Simply Recipes elaborates:

If you have a baking recipe that calls for baking soda, and you only have baking powder, you may be able to substitute, but you will need 2 or 3 times as much baking powder for the same amount of baking soda to get the same amount of leavening power, and you may end up with something that’s a little bitter tasting, depending on the recipe.

If you need baking powder but only have baking soda:

Since baking soda’s an ingredient in baking powder, this one’s a little easier. Decrease the amount used by about a third, since baking soda’s more powerful. (So if, for example, the recipe calls for 3 teaspoons of baking powder, use only 1 teaspoon of baking soda.) Then, be sure to add an additional acidic element: for every ½ teaspoon of baking soda you use, add 1 teaspoon of vinegar or lemon juice.

So wait, does this all mean I can make my own baking powder?

It does! What’s more, since baking powder has a short shelf life, especially compared to baking soda, it might make more sense for you to just make your own when you need it, especially if you live in a humid environment. Just mix one part baking soda with two parts cream of tartar – 1 teaspoon of baking soda plus 2 teaspoons of cream of tartar for every required tablespoon of baking powder – and you’re good to go.

Hold up. Baking powder has a short shelf life? How long do these things last?

Baking soda can last for a long time if you store it correctly in a dry, cool place. Baking powder can last anywhere from three months to a year, but once it’s open, any humidity will make it go bad fast.

Well that has me worried. Are there any ways I can check to see if they’re still good?

Yes, there are! Just perform these simple tests:

Baking Soda:

1. Measure out a half cup of hot water. Add ¼ teaspoon of white or apple cider vinegar.
2. Drop a bit of the baking soda into the hot water.
3. See if it bubbles and fizzes. Did it? It’s still good to go!

You can also skip the hot water and see if the baking soda fizzes just by dropping some directly into 3 tablespoons of white distilled vinegar.

Baking Powder:

You do the same exact test— just without vinegar!

1. Measure out a half cup of hot water.
2. Drop a bit of the baking powder into the hot water.
3. See if it bubbles and fizzes. Did it? It’s still good to go!

Wrap-Up

So there we have it. Baking soda versus baking powder— very similar things, very related things, but not the same thing. Keep the leavening properties in mind, remember to balance the “basic” with an acid for taste that’s good, not bitter, and you should be good to go. Read your recipes, experiment when you feel brave, but most of all, remember to have fun! It might be chemistry, but it’s science you can eat. What’s better than that?

Do you have any baking soda versus baking powder wisdom to share? Have you ever accidentally used one when you meant to use the other? How did it turn out for you?

Sources: Sally’s Baking Addiction
Simply Recipes