Baking soda and baking powder are staples in a baker's kitchen and are very common ingredients in cookies, cakes, and other baked goods. However, the role that they play in baking and the differences between the two ingredients can be confusing! Keep reading to learn the difference between baking soda and baking powder (plus how to know if your ingredients are fresh or if it's time to replace them).
What is the difference between baking soda and baking powder?
Both are chemical leaveners, which means that they "lighten" dough and batter. They are what make our cookies and cakes rise. But they are not the same, and they are not interchangeable.
What is baking soda?
Baking soda is sodium bicarbonate. When activated, baking soda releases a gas (carbon dioxide) into our baked goods, causing them to rise.
Baking soda is activated when it is mixed with an acid. So in baking, we activate baking soda by pairing it with an acidic ingredient (such as lemon juice, buttermilk, or yogurt) in our recipes.
Baking soda can be a little bit tricky, because you need enough acid in your recipe to activate all of the baking soda. If you have leftover baking soda that isn't activated, you could end up with a slightly metallic taste in your baked goods. Ick! This is why it's important to follow your recipe and measure your ingredients properly.
What is baking powder?
Baking powder is a mixture of sodium bicarbonate (baking soda), powdered acid, and cornstarch. Like baking soda, when activated, baking powder releases a gas (carbon dioxide) into our baked goods, causing them to rise.
Today, most baking powder is double-acting. This means that it is activated twice: first when it is mixed with a liquid, and again when it is heated. In baking, our baking powder is first activated when it's added to our batter, and it's activated again when it's heated in the oven. Since baking powder already contains an acid, it is not necessary to mix baking powder with an acidic ingredient in order to activate it.
When should you replace your baking soda and baking powder?
Generally, it's best to replace your baking soda and baking powder three to six months after opening to ensure that they're fresh. Baking soda and baking powder that have been open for some time or that have passed their expiration date will lose their potency and will not help your baked goods to rise properly.
To test baking soda for freshness, place a spoonful of baking soda in a bowl and add a splash of vinegar or lemon juice. The mixture should become very fizzy. If there is little or no fizzing, the baking soda should be replaced.
To test baking powder for freshness, pour some warm water into a bowl and then add a spoonful of baking powder. The mixture should become fizzy. If there is no reaction, the baking powder should be replaced.
Tejaswi Ramesh
Hi Allison. For a cookie reciepe containing millet&whole wheat flour, with some powdered white sugar,cardamom powder,unsalted butter & baking soda, which of the above ingredients will act as the acid to activate the soda? or do we need to add acid sperately? which acid would you recommoned? The cookies turned out a litlle hard than expected.
Allison Ferraro
Hi Tejaswi! None of these other ingredients that you mentioned are acidic, so I'm not sure how the baking soda in the recipe was intended to be activated. You could consider trying baking powder instead to see if it yields your desired result (you'll want to use about 4 times as much baking powder as you did soda). Since I'm not familiar with this recipe, I'm not able to confidently share a recommendation for adding an acidic ingredient. And since these cookies don't contain an ingredient that helps to soften the dough - like egg, brown sugar, or cornstarch - I'm not surprised that you found them to be hard. The best bet may be to find another recipe that's better suited to what you're looking for. Happy baking!
- Allison
Pat
We’re missing a critical wonder of chemistry here… There are many recipes that use baking soda for leavening, yet have no acidic components. The mystery of how this can actually leaven anything lies in the fact that when sodium bicarbonate (NaHCO3) is heated above 176 degrees Fahrenheit, a chemical decomposition reaction kicks in that breaks down NaHCO3 into three separate compounds: 1) sodium carbonate (Na2CO3), 2) water (H2O), and 3) our coveted leavening agent, carbon dioxide (CO2)! No acid needed… just heat! Acids are required below 176 degrees Fahrenheit, but not above. (Which, by the way, is why cookie dough can be refrigerated for days or frozen for months, and the cookie will still rise when baked.) Incidentally, the higher the temperature, the faster the decomposition reaction will complete.
alice
WHICH is used for CLEANING!?
Allison
Hi Alice! Baking soda can be used for various cleaning purposes.
- Allison