The Difference Between Baking Soda and Baking Powder

This is what happens when baking soda and acid (in this case vinegar) interact. Photo credit: Kate Ter Haar, via Wikimedia Commons.
This is what happens when baking soda and acid (in this case vinegar) interact. Photo credit: Kate Ter Haar, via Wikimedia Commons.

Note: This post is part of an ongoing series in which we try to answer questions about the science behind food – from farm to fork. If you have a food-related question, please let me know at matt_shipman@ncsu.edu.

What’s the difference between baking soda and baking powder? Short answer: acid. But it can make a big difference for baked goods, so let’s explain.

Baking soda has only one ingredient: sodium bicarbonate. Sodium bicarbonate is a base that reacts when it comes into contact with acids, like buttermilk, yogurt or vinegar. This reaction produces carbon dioxide (CO2) in the form of bubbles, like a liquid foam (think of the grade school experiments involving fake volcanoes, vinegar and baking soda). When making baked goods, the process is called “chemical leavening,” because the trapped CO2 gas makes the dough or batter rise.

But when baking soda comes into contact with an acid, it pretty much reacts immediately. And that’s a problem.

For many baking recipes, you want an extended reaction, so that the rising doesn’t take place all at once.

Baking powder addresses this problem because it is “double acting” – it has different ingredients that create CO2 gas at different stages of the baking process.

All baking powders contain sodium bicarbonate (just like baking soda). But baking powder also contains two acids.  One of these acids is called monocalcium phosphate. Monocalcium phosphate doesn’t react with the sodium bicarbonate while it’s dry. But as soon as the baking powder is stirred into a wet dough or batter, the two ingredients begin to react, releasing bubbles of CO2 and causing chemical leavening.

But to extend the chemical leavening process, baking powder also contains a second acid, either sodium acid pyrophosphate or sodium aluminum sulfate. Neither of these acids react with sodium bicarbonate until they are both: A) wet (i.e., stirred into the batter) and B) hot.

In other words, sodium acid pyrophosphate and sodium aluminum sulfate won’t start reacting with the sodium bicarbonate until after you’ve put the dough or batter in the oven. This means that the batter rises for a longer period of time, making lots of bubbles (and a fluffier cake, muffin, or whatever).

At some point during the baking process, the liquid foam of rising batter becomes a solid foam, because the batter “sets.” This is one reason eggs are so common in baking recipes.

The proteins in eggs become irreversibly denatured when exposed to heat (i.e., the proteins unfold and cannot refold into their original shape). These altered egg proteins essentially give the liquid foam a solid structure, allowing it to hold its shape.

By comparison, in recipes that use yeast as a leavening agent, the gluten proteins in flour serve a role similar to that of egg proteins in most chemically-leavened baked goods in the sense that they help to trap air bubbles until the dough sets. (That’s why bread flour has more protein than cake flour.)

Note: Special thanks go to Keith Harris, an associate professor in the Food, Bioprocessing and Nutrition Sciences Department at NC State and all-around food chemistry enthusiast. He explained baking soda and baking powder to me in very accessible terms. He gets credit for everything I got right here – but I’ll take credit for any mistakes that slipped through the cracks.

46 responses on “The Difference Between Baking Soda and Baking Powder

  1. Bob Butler says:

    Thanks for the answer,
    I had no idea it was so technical.
    A top UK chef, Jamie Oliver, did say when to use each, but I couldn’t remember why.
    thanks again
    regards
    Bob

  2. Teresa Sully says:

    Ok then what is the difference between baking soda, baking powder and bi carb soda..? Or is there another player … bi carb powder… btw I’m Australian and we usually deal with the latter two mentioned here. Thanks, Teresa.

    1. mk swamy says:

      can you please tell me where to use cooking soda and baking soda can one consume in the
      food pl…… swamy

  3. Gladys says:

    Teresa Sully, you are the best!!! x

  4. Marge says:

    Can baking soda cause hair loss?

  5. Shittu says:

    that’s cool but how about soda lime and caustic soda ?

  6. Shittu says:

    and uhm quicklime and slaked lime

  7. neeraj says:

    neeraj kumar says Aug 1 …2015 11:53 pm..Thanks for Keith Harris difference bewteen baking powder and baking soda. ……

  8. Mike Heath says:

    The answer to your question Teresa Sully is right there in the text if you take the trouble to read it-carefully.

  9. Erika says:

    what happens when both baking soda and baking powder (same amount each) are used in baked goods together?
    Thanks for your answer

    1. Robyn says:

      Using too much baking powder will make your bread rise rapidly, the bubbles get too large and collapse. I had this happen today while I was adjusting an oatmeal banana bread recipe to see how high I could get it to rise.

  10. Lenora Neeley says:

    Thank you for clearing that up. Have more questions at intervals. Just starting to cook seriously.

  11. saad ali says:

    A very good answer by u thanks
    I did not know about it

  12. Ali :) says:

    Thank you so much!!! This helped me withe my science fair project and better understand the differences between the two!!!! Thank you so much!!!!!! ;D

  13. Francis D'Souza says:

    Hi
    I read that a natural remedy for Constipation is to take Baking Soda with warm water. Instead of taking Baking Soda, if I take baking powder will it do any harm for my stomach.

  14. Francis D'Souza says:

    Hi
    I have also read that Baking Soda is good for producing testosterone. Instead of using Baking Soda if I use Baking Powder (because I have it at home) will it do any harm for my stomach.

  15. Rabeela Uqaili says:

    I didnt want to hav the answer in science language. I want to knw what is the purpose of using baking soda in a cake and baking powder in a cake. Also, when to use both?
    Can someone plz answer me?

    1. Robyn says:

      Using too much baking soda can leave a bitter taste in some lightly flavored batters so baking powder is added also to prevent this. Both the baking soda and baking powder start the rise immediately when an acid and liquid are added. If double acting, the baking powder will continue to rise from the heat of the oven.

      The reason eggs are added is because the heat of the oven changes the structure of the egg protein so that the moist foam of the co2 bubbles is ‘set’ by the ‘cooked’ egg protein and the risen batter holds its shape. This is why most recipes say to mix the eggs into the batter until completely incorporated; it spreads the egg protein evenly throughout the batter to ensure an even rise with the baked goods.

      In the case of your cookies you get a lighter fluffier cookie than without both.

  16. Nor-Shore says:

    How fascinating! Thank you for explaining the difference between baking soda and baking powder! That’s another great “food” question for my foodie friends at the next cocktail party! I’ll use that one next after asking, “What’s the difference between a holandaise sauce and a bernaise sauce? Just the addition of ONE ITEM! Add terragon to a holandaise and voila, you’ve got a bernaise!

  17. Colin Courtney says:

    Thanks for that explanation it settles an argument I was told they were the same but have seen recipes which call for both products which brought up the discussion.

  18. EK Leslie says:

    Thank you so much for this!

  19. Vasu P says:

    For those who want to reduce sodium intake, is poassiuim bi-carbonate (and baking powder with potassium based acidic salts) useful for baking? Are these available ?

  20. Tavaine says:

    which ingredient in the baking powder causes the dough to roll easily

  21. Francesco Martiradonna says:

    I am sorry to get out of the subject but I would like to mention another use for Baking soda. When I was small and had a stomach ache or acidity my mother would squeeze some fresh lemon juice, add some sugar and when all sugar was melted she would add a tip of a teaspoon of Baking Powder and stir. It did foam up to the glass rim and it was delicious! And in a short time my stomach did not hurt anymore! (This must have been an old natural Italian remedy I guess, it worked every time!) Franco M

    1. Francesco Martiradonna says:

      I can not find anything else to be filled

  22. Cindy A says:

    Thanks for the explanations. A side question, I have been using baking soda for cleaning purposes, wonder baking power will do the job? I m no good in science.

  23. J. Acungwire says:

    I thank everybody foe the wonderful contribution to this discussion of baking soda and baking powder. I have read in some papers that baking soda kills cancer cells, bacterial and viruses. Can someone help to give more information on this.

  24. Cooliodudet says:

    Cool I Like It

  25. Thonia says:

    I was impressed and satisfied with the answer I got. Nice job

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