Baking soda, baking powder - what's the difference? Both are white powders, odorless and nearly indistinguishable. Yet both help your baked goods to rise. Without them (or another leavener like yeast or beaten egg whites) all of our breads and cakes would be very flat and dense.
We were curious about why recipes call for one over the other, and we went on a hunt to find out.
Baking soda is also known by its chemist term: sodium bicarbonate. When heated, this chemical compound forms carbon dioxide gas - making your breads and cookies rise. That's not all it produces, though, which can be a problem...
When heated, sodium bicarbonate also produces sodium carbonate, which doesn't taste so great. It leaves an unpleasant, alkaline flavor behind. But if you mix baking soda with an acid (like lemon juice or another citric acid carrier) then the sodium carbonate is partially neutralized and leaves behind less aftertaste. This acid also helps the carbon dioxide gas release more quickly.
Baking powder is basically just baking soda with acid added in. It has just enough acid to use up the sodium carbonate. Shirley Corriher in her great book Cookwise says that 1 teaspoon baking powder contains 1/4 teaspoon baking soda. The other 3/4 teaspoon contains the acid and cornstarch.
Depending on how much acid is in the baking powder (remember how it helps release the carbon dioxide?) the baking powder can be labeled as fast-acting, slow-acting, and double-acting. Most baking powders are double-acting and will release only a small amount of gas during mixing; the majority will release in the hot oven.
This may all be very interesting if you are into food chemistry, but what's the takeaway for the home cook?
First, remember that baking soda works with foods that are acidic. If you are making biscuits that call for buttermilk and baking soda, but you substitute regular milk, your biscuits may not rise. Buttermilk is acidic and releases the raising power in the baking soda. Add a tablespoon of vinegar to each cup of milk.
On the other hand, what if you add an acidic ingredient to a recipe with baking powder? You will need to add a little soda. Let's say you are making cookies and substituting 1/2 cup lemon juice for the water in order to make lemon cookies. The recipe calls for 2 teaspoons of baking powder, but you will need to neutralize the acid in the lemon juice. Substitute baking soda for one teaspoon of the baking powder. Corriher says that baking soda is 4 times as powerful as baking powder, so use only 1/4 teaspoon baking soda for each teaspoon of baking powder in the original recipe.
very edumacational.
view spossberg's profile
That's very interesting, and does explain some differences among recipes. I'd never remember it, though; I'll just have to continue to rely on recipes.
view Joan A.'s profile
Any tips on storing baking soda once it's opened? I'm having some trouble with baked goods falling flat, and I wonder if old soda could be the culprit.
view SisterRae's profile
That explains my heavy-as-a-rock cornbread...I should have known that substituting regular milk for buttermilk was going to have consequences.
view Michelle of Montreal's profile
I was pondering this very question whilst making skillet cornbread the other day. Thanks!
view catlike's profile
In one or another episode of Good Eats, Alton Brown says that if you combine 1 C skim milk and 1 T fresh lemon juice, let it hang out for five minutes or so, you can substitute it for buttermilk. I think he even said that if you put it in the fridge for a little while, it will even thicken up a bit. I was happy to know this since my cornbread urge strikes frequently and unexpectedly.
view LauraII's profile
I am going to print out this post and put it in my recipe binder. I have been wanting to progress beyond just blindly following recipes, and understanding how food chemistry relates to everyday cooking situations really helps in that endeavor. Thanks!
view J's profile
SisterRae--you should be able to store your baking soda in your pantry at room temperature without any ill effects. It doesn't need to be in an air tight container or anything, though it will pick up odors so keep it away from strong smelling stuff. Baking soda is stable and doesn't expire, so if your baked goods are falling flat, it's likely something else. (On the other hand, baking POWDER has a shelf life of about 9 months to a year.) Hope that helps!
view EmmaC's profile
Is there a difference when using them for cleaning, like making a paste to scrub something?
view 2T's profile
what is the acid in chocolate chip cookies that neutralizes the baking soda? most c-chip recipes call for soda, not powder, maybe explaining an off-taste you sometimes get.
when you don't have buttermilk, use yogurt! if you need it thinner, add milk or water. sometimes you don't have a lemon tree outside, but you always have yogurt in the frig!
view Joan Vignocchi's profile
2T - I would imagine baking soda is a better cleaner because it is 100% sodium bicarbonate. Baking powder, on the other hand is up to 75% cornstarch.
Joan - that's a great question. Corriher gives a list of some things that contain mild acids. They include: chocolate, honey, molasses, sour cream, and brown sugar. Maybe the chocolate and brown sugar and cookies are what react?
view faith's profile
My mother always taught me to add some vinegar to any baking recipe that called for baking soda. I thought she was crazy until I tried it and made my best tasting batch of cookies ever. I usually use a tbsp. of vinegar for every tsp. of baking soda.
view carmelita 's profile
And, see what happens when you inadvertanly mess up by looking at my baking disasters post.
view kaanswfm's profile