The Nov 8, 2008 Splendid Table podcast featuring Shirley Corriher has a wonderful summation of how leavening works in baking.

Chemical leavening in baking (baking soda and baking powder) don’t make the bubbles in your batter: they make them bigger. (Says Corriher. Having played with vinegar and baking soda I disagree… ideas?)

So where do those bubbles come from then? In the baking example mentioned in the podcast- a cookie recipe- the bubbles come from the creaming step. This is when the butter and sugar are combined till light and fluffy. Shirley Corriher recommends that the creaming step take 7 minutes in an upright mixer, longer if using a hand held mixer. (So what about pancake batter? It doesn’t have a creaming step.)

Baking powder contains soda in it and the right amount of acids to utilize all of that soda. With baking soda you have to have something acidic in your batter to react with it, and its an instant action- vs
the baking powder which is double or triple action. So we usually see baking soda in buttermilk recipes as buttermilk is acidic.

Baking Rules

Is too much baking soda or baking powder bad? Theoretically yes.
Too much leavening will over-inflate your bubbles, causing them to break and not lend as much structural support to your batter.

-guess who’ll be readjusting all of her blog’s baking recipes now.

Summarized on the Nov 8, 2008 Splendid Table podcast featuring Shirley Corriher.


posted January 2nd, 2009 at 3:22 pm

This is awesome information – thanks! I love the science side of baking.

- Erin
posted January 6th, 2009 at 1:02 am

[...] soda, Link, tips |   Brownie Points recently posted a rather interesting article detailing baking powder and baking soda, how they are alike and how they are not. Definitely worth a read (and a listen to the podcast [...]

posted January 6th, 2009 at 7:27 am

Yeah, I listened to the same podcast. Another recent Splendid Table talks about cookies. Now that I’m back in Indiana from a trip to New Orleans, I plan on ordering her newest book.

- Jeromy French
posted January 7th, 2009 at 1:46 pm

I just made a batch of peanut butter choc chip cookies a couple days ago and had the creaming done when I realized I was out of baking soda- the recipe called for 1/2 tsp. I though about just leaving it out entirely, since i couldn’t think of any ingredient that is acidic- maybe the egg a tad?-and the PB definitely makes the cookies dense anyway- but I threw in about a tsp of baking powder (which contains baking soda) and the cookies were awesome.What gives?

Baking powder contains baking soda- as you said, and it also contains the proper amount of acid to activate the baking soda completely. Baking powder doesn’t rely on the ingredients of your recipe to work, vs baking soda.


- Rebecca
posted January 9th, 2009 at 8:59 am

“So what about pancake batter? It doesn’t have a creaming step.”

That would be, I think, why it’s so important not to over-mix pancake batter. In this case, I’d wager that the air in the recipe is in the flour. If the ingredients are just barely combined, the flour would retain more of its air, whereas over-mixing would beat out all the air and result in runny pancakes.

I think this calls for an experiment: pancakes with sifted flour versus the same recipe with unsifted flour.

- Karen
posted January 14th, 2009 at 10:22 pm

I wrote a post about leaveners not that long ago.

It’s good to see that baking fundamentals are still being written about. (We all have to learn from somewhere.)

posted February 23rd, 2009 at 1:29 am

When you combine acetic acid (vinegar) and sodium bicarbonate (baking soda), eventually water and carbon dioxide are released (the correct scientific term is “evolved”). Here’s the step-by-step chemical formula if you’re interested:

I’m not entirely clear on this, but I think what Shirley Corriher is saying is that the CO2 is already there, but just bound up in baking soda and thus not in a usable (that is, gaseous) form until a chemical reaction takes place. It’s not like we’re smashing carbon and oxygen atoms together to form CO2. To bolster this idea, baking soda by itself will decompose and release water and carbon dioxide at high (over 250F) temperatures (this last sentence is based on “The Science of Bakery Products,” pp. 70-71).

There’s also an issue of surface tension that I won’t go into except to say that if bubbles already exist in the dough or batter, then it’s much easier for the gas released by the leavening agent to latch on to them and make them bigger.

Creaming isn’t the only way to form bubbles. Any mixing action (that I can think of, anyway) will incorporate air into the batter or dough, but different mixing methods yield different bubble sizes.

Sifting flour does add air into the mixture, but my understanding for why you don’t want to overmix pancake batter is because of the gluten in the flour. The more you work the flour, the more the gluten will develop — you’re kneading bread, essentially — and you’ll end up with a tough and chewy pancake instead of a light and fluffy one.

posted March 1st, 2009 at 9:16 pm

IIRC, baking powder contains baking soda and cream of tartar. That’s why most baking powder is usually labeled “double rising” or the like. The baking powder reacts quickly and the cream of tartar is slower and longer lasting. You’ll find a few recipes (snickerdoodles come to mind) call for cream of tartar (I guess the ratio in baking powder is wrong for these? Not entirely sure why… they are fairly flat cookies).

- maryr
posted March 1st, 2009 at 9:18 pm

PS: I meant to add that Best Recipes is a great cookbook for the science/basics behind components in recipes.

- maryr
posted March 4th, 2009 at 6:33 pm

maryr, that is incorrect. All baking powders are combinations of alkaline and acidic components. The alkaline component is usually baking soda. The acidic component can be either a fast- or slow-acting acid. Double-acting powders contain both types of acids, hence the two actions. Cream of tartar is a fast-acting acid. I wrote a (long) post about baking powder in my blog recently; you can see it here:

posted March 18th, 2009 at 10:35 pm

OMG!!! 1/4 tbsp for 1 cup of flour!!!

I have read recipes with way more than that… no wonder my cupcakes turned out bitter

- Jazzle
posted July 24th, 2019 at 8:11 pm

This is vital information… I didn’t know this and couldn’t figure out why (structurally) my cakes all fell apart. Well this is definitely why! I’m totally listening to your advice and following your instructions. Thanks so much.
Kitchen Scales

- Jenny

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