The Difference Between Baking Powder and Baking Soda

Baking powder and baking soda are common ingredients, you've probably used them yourself in countless recipes for everything from waffles to cupcakes. But have you ever wondered why we need both? Does using one over the other matter in terms of our end result? Are baking soda and baking powder really that different?

Well, yes and no. Baking soda and baking powder aren't the same thing, although baking soda is one of the main ingredients that makes modern baking powder work. They both serve a similar purpose in the kitchen: to leaven baked goods and make them light and fluffy. To understand how this is accomplished, we need to take a closer look at the chemical process that occurs when we cook with baking powder and baking soda.

What is Baking Soda?

Sodium bicarbonate (otherwise known as baking soda) is an unadulterated amphoteric salt compound¹ that is refined from a mineral known as trona. This non-marine evaporate mineral exists in large, naturally occurring deposits all over the world.

Baking soda can also be synthesized using a method known as the Solvay process, but since one of the largest trona deposits in the world can be found right here in the U.S.A., nearly all our baking soda is naturally mined from the earth. Located in Green River, Wyo.², this particular trona deposit is estimated to be 127 billion tons, about 40 billion tons of which is viable for mining – enough to last the human race approximately 2,350 years at our current rate of consumption.

After mining, the trona ore is crushed and heated, dissipating unwanted gasses and forming sodium carbonate. Further processing then converts the highly caustic sodium carbonate into the gentler form of sodium bicarbonate, or baking soda, that is found in kitchens all around the world today. If you are living and cooking anywhere in the U.S., it's highly likely the baking soda in your kitchen came from natural trona ore mined domestically in Wyoming.

Classified as a base, baking soda has a pH level of about 9 and alters the acidity level of food when added to any recipe. When it comes into direct contact with common kitchen acids such as lemon juice, vinegar, or buttermilk, it reacts quickly to produce instant carbon dioxide bubbles. Although this fizzy reaction may have looked cool in that fourth grade build-your-own-volcano science project, it also serves an important purpose in the kitchen.

What is Baking Powder?

Baking powder is a slightly more complex blend of ingredients that can produce a noticeably different effect and flavor when used in food. Usually created from a mixture of baking soda, monocalcium phosphate, and sodium aluminum sulphate, baking powder was first invented nearly 200 years ago by a chemist named Alfred Bird.

Until the advent of baking powder, most baked goods were leavened using yeast or eggs, both of which involve time-consuming processes and can be unpredictable at best. Enter Elizabeth Bird, Alfred Bird's wife, who was, unfortunately, allergic to both yeast and eggs. Her husband soon developed the first baking powder³, made of tartaric acid (also known as cream of tartar), baking soda, and cornstarch.

After he perfected the formula for the world's first single-acting baking powder, Bird eventually sold it to both the Army and Navy. Over time, the formula was altered to use the more cost-efficient monocalcium phosphate in place of the original cream of tartar, achieving the same effect at a reduced cost.

A few decades later, double-acting baking powder⁴ was invented and sold under the name of Calumet Baking Powder. By adding sodium aluminum sulphate to the mix, inventors George Campbell Rew and William M. Wright were able to alter the leavening action of the powder. Since sodium aluminum sulfate is insoluble, it doesn't react with sodium bicarbonate until it reaches its melting point of 140 degrees Fahrenheit – which is incidentally right around the same temperature that baked goods begin to structurally change and soften in the heat of the oven.

Why We Use Baking Powder & Baking Soda

Since most of us aren't allergic, why don't we just use yeast or eggs instead? Unlike yeast, baking powder and baking soda are instant. Yeast requires separate preparation before the recipe even starts and can take several hours to activate and fully rise. Once it's ready, you're left with a restricted window of time to use the activated yeast, not to mention the extra dishes dirtied in the process.

Using eggs to leaven baked goods also requires additional supplies and labor as the cook must first separate the yolks and then beat the egg whites for an extended period in an isolated container before adding them to the batter – and even then there is a danger of overmixing when combining them with other ingredients and causing the carefully whipped whites to lose their structure and fall flat.

For the modern cook, baking powder is simplicity in a can, a shortcut to raising all types of batters and doughs with reduced investment of valuable time and energy into the preparation process.

Baking Soda vs Baking Powder in the Kitchen

Okay, that's all very interesting, but how are they used in the kitchen and what does this have to do with your cake mix?

Baking soda, being quick and single acting, is often used to leaven items that will be cooked immediately after mixing such as pancakes, some fried batters, scones, and muffins. To activate the baking soda and get a rise out of your food, there must be enough acid in the recipe to offset the baking soda's basic nature⁵. Commonly used acids include lemon juice, vinegar, buttermilk, yogurt, sour cream, coffee, or our old friend cream of tartar.

Baking soda is about four times as strong as baking powder and alters the pH of dough in a way baking powder doesn't. The upshot of this is a thicker texture and weakened gluten – a combination that leads to a soft yet firm mouthfeel. On the downside, baking soda is strong, and adding too much can leave your baked goods tasting salty and metallic, so it's best to follow a "less is more" strategy.

Baking powder, however, is a little bit more foolproof. Its all-in-one formula doesn't require any specific acids to activate, since it's activated first by moisture when it's mixed into the dough and then again by the heat of the oven. Useful for leavening recipes that don't have other sources of acid, baking powder enables the chef to prepare a batter or dough a bit ahead of time without it running out of air and falling flat too quickly. For a light and fluffy baked good such as a slice of bread or a biscuit, this double-acting process is essential for adding enough volume to the mix.

Substituting Baking Soda & Baking Powder

So what happens if you find yourself halfway through a recipe that calls for baking powder or baking soda that you don't have, with no time to get to the store? Can you use baking soda in place of baking powder, or baking powder in place of baking soda? Well, the short answer is yes, although a simple 1:1 substitution won't work.

Substituting Baking Soda for Baking Powder

If you're going to substitute baking soda for baking powder, you will need to ensure you've included enough acid in the recipe to fully activate the baking soda. For example, you might swap regular milk for buttermilk, or add a teaspoon or two of lemon juice. Typically, one cup of buttermilk or one teaspoon of lemon juice is enough to fully activate ¹⁄₂ teaspoon of baking soda, so plan accordingly.

Don't forget – baking soda is much stronger than baking powder, so you will need to first calculate the reduced amount of baking soda needed before determining how much and what type of acid to add to your recipe. If your recipe calls for 1 full teaspoon of baking powder, you will only need ¹⁄₄ teaspoon of baking soda to achieve a similar result without adding any metallic aftertaste.

If your recipe doesn't include any acidic liquids and adding some to the mix is not an option, you can always opt to create your own baking powder¹ by using a few common ingredients from your baking cupboard. Combining ¹⁄₂ teaspoon of baking soda with 1 ¹⁄₄ teaspoon cream of tartar will equal the same effect as 2 teaspoons of premixed commercial baking powder (and adding a small pinch of cornstarch can help prevent clumping if you intend to store your homemade baking powder in the cupboard).

Substituting Baking Powder for Baking Soda

Okay, we've covered swapping baking soda for baking powder, but what if you need to do the opposite?

Again, there isn't really a simple answer. Technically, you can substitute baking powder for baking soda, but that doesn't mean you should. Swapping a straightforward ingredient like baking soda for a complex formula such as baking powder will cause a variety of changes to your mixture, some of which can be quite unexpected.

To take the place of 1 teaspoon of baking soda, you need to add 3 to 4 teaspoons of baking powder, an amount that can leave your end product with an unpleasant and vaguely bitter flavor. On top of that, you would need to make alterations to the recipe beyond just swapping baking powder for baking soda, such as reducing the amount of salt and any acidic ingredients in the mixture – which can leave your end product dry or cause it to fall flat if you accidentally remove too much.

At the end of the day, your best bet if you run out of baking soda isn't to swap it out with baking powder – it's to take a quick run to the store and restock. However, if there's simply no other alternative and you're out of time, you can use the information in this article to tweak the overall formula of your dough and proceed with caution. Just don't be too disappointed if the end result doesn't quite rise to meet your expectations.

References

1. Sodium Bicarbonate Formula. Soft Schools. Accessed May 2021.
2. Trona Mining. Wyoming Mining Association. Accessed May 2021.
3. The History of Baking Powder. Kudos Blends. Accessed May 2021.
4. Double-Acting Baking Powder. Bakerpedia. Accessed May 2021.
5. What Does Baking Soda Do and How Does it Work?. Bob's Red Mill. Accessed May 2021.
6. Baking Soda. Bon Appetit. Accessed May 2021.