Learn the difference between baking soda and baking powder and become a better baker. The two cooking ingredients are both white powders that act as leavening agents. In other words, they make baked goods rise. Both cause rising by making carbon dioxide gas bubbles that expand once a recipe hits the heat of the oven. But, baking soda and baking powder don’t taste the same and don’t behave quite the same, chemically. Here’s what you need to know.
What Is Baking Soda?
Baking soda is the common name for sodium bicarbonate (NaHCO3). It is the usual leavening agents in cookies, soda bread, and quick breads. This crystalline white powder is a weak base. What that means is that it reacts with acidic ingredients, such as cream of tartar, lemon juice, vinegar, cocoa, buttermilk, or yogurt. The reaction produces carbon dioxide gas bubbles. Baking the recipe expands these bubbles and makes baked goods rise.
NaHCO3 + H+ → Na+ + CO2 + H2O
Baking soda also undergoes thermal decomposition during baking, producing some additional carbon dioxide once the recipe goes in the oven.
2 NaHCO3 → Na2CO3 + H2O + CO2
But, if you don’t have an acidic ingredient in the recipe neutralizing some of the sodium bicarbonate, the end result may taste bitter, soapy, and salty! Use caution if you adjust the recipe. Either substitute one acidic ingredient for another or else add some cream of tartar if you swap a non-acidic ingredient for an acidic one. For example, if you use water instead of buttermilk, you’ll lose the acid in the recipe and will need to compensate for it. A better substitute is regular milk, plus a bit of lemon juice or vinegar.
What Is Baking Powder?
Baking powder is the leaving agent usually found in cake recipes, although you see it in some cookies, muffins, and breads, too. It is a mixture of baking soda, a weak acid, and a dry powder that prevents the other two ingredients from reacting prematurely. There are many baking powder formulas. A common example uses baking soda, cream of tartar (the weak acid), and corn starch (the drying agent). Other baking powder formulations use monocalcium phosphate, sodium aluminum sulfate, and/or sodium acid pyrophosphate as their weakly acidic ingredient.
Adding liquid in a recipe with baking powder immediately releases carbon dioxide bubbles as the sodium bicarbonate and weak acid react. These bubble expand in the oven and make the mixture rise. Single-acting baking powder only rises from this initial reaction, so it’s important to bake a recipe immediately after mixing it so it does not lose the carbon dioxide bubbles. Double-acting baking powder contains two weak acids. One acts immediately, but the other reacts more slowly, so the mixture continues to rise in the oven. This makes baking the recipe less time-critical and adds extra lift to the final product.
Recipes that use baking powder don’t require an acidic ingredient in order to rise. However, they may still include one for other reasons, such as flavor.
Using Both Baking Soda and Baking Powder
Some recipes call for both baking soda and baking powder. There are two main reasons for this. Sometimes a recipe needs more lift that it gets from the acidic ingredient reacting with sodium bicarbonate. The other reason for using both ingredients is so the final product retains a tangy flavor. The leavening ingredients also influence how baked goods brown and crisp. If you adjust a recipe containing both baking soda and baking powder, consider the effect a change has on both the texture and taste.
How to Substitute Baking Soda and Baking Powder
You can substitute baking soda and baking powder in recipes, but expect a change in the flavor and maybe even texture of the final product. Mainly, keep in mind you need an acidic ingredient for baking soda and a watery liquid for baking powder.
Using Baking Powder Instead of Baking Soda
You can use baking powder instead of baking soda in a recipe. The only thing is, you can’t use the same amount. Use three to four times more baking powder than baking soda, because baking powder is not pure sodium bicarbonate. For example, if a recipe calls for 1 tsp of baking soda, use 3 tsp of baking powder. The substitution may add a bit of bitterness or saltiness to the final flavor. If the recipe calls for salt, reduce the amount.
Using Baking Soda Instead of Baking Powder
Baking soda is more potent than baking powder, so you need less of it if you substitute one for the other. Keep in mind, baking soda needs an acidic ingredient which might be lacking in the original recipe.
One option is swapping an acidic liquid for the original liquid in the recipe or adding an acidic ingredient, like yogurt, lemon juice, or vinegar.
Another option is using homemade baking powder. Make baking powder by combining two teaspoons of cream of tartar with one teaspoon of baking soda. If you use homemade baking powder, use it exactly like the store-bought (don’t change the amount in the recipe).
Test for Freshness
Both baking soda and baking powder have expiration dates. The shelf life depends mainly on exposure to air and humidity, but high temperatures also reduce how long it stays fresh. Unopened containers last about two years, but the shelf life drops to about six months to a year once opened. Store baking soda and baking powder in sealed containers in a cool, dry place.
Test Baking Soda for Freshness
Baking soda reacts with acid, so simply mix a bit of baking soda with either vinegar or lemon juice. If you see and hear fizzing and bubbling, the baking powder is still good for recipes. On the other hand, if the fizz is weak or nonexistent, it’s time to visit the store for a replacement.
Test Baking Powder for Freshness
Baking powder reacts with water, so mix 2 teaspoons of baking powder into a cup of hot water. If you get immediate fizzing, the product is still good. If you don’t get fizzing or else it’s weak, replace your baking powder with a fresh container. In a pinch, you can make homemade baking powder from baking soda and cream of tartar.
- Brodie, J.; Godber, J. (2001). “Bakery Processes, Chemical Leavening Agents” in Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons. doi:10.1002/0471238961.0308051303082114.a01.pub2
- Lindsay, Robert C. (1996). Owen R. Fennema (ed.). Food Chemistry (3rd ed.). CRC Press.
- Matz, Samuel A. (1992). Bakery Technology and Engineering (3rd ed.). Springer.
- McGee, Harold (2004). On Food and Cooking (revised ed.). Scribner-Simon & Schuster. ISBN 9781416556374.
- Savoie, Lauren (2015). “Taste Test: Baking Powder”. Cook’s Country (66): 31. ISSN 1552-1990.
- Stauffer, Clyde E.; Beech, G. (1990). Functional Additives for Bakery Foods. Springer.