Baking Soda vs. Baking Powder

Q: What is the difference between baking soda and baking powder and how are they used. Can one be substituted for the other?

Baking soda and baking powder are both chemical leaveners used to make baked goods such as cakes and muffins.  Baking soda has some other culinary uses, not discussed here.  In recipes calling for baking powder, baking soda can be used, along with some cornstarch and cream of tartar.  Baking powder cannot, however, be used to replace baking soda.

The chemical in baking soda is bicarbonate of soda (NaHCO₃).  When combined with an acidic ingredient, such as vinegar or the lactic acid in buttermilk, baking soda releases carbon dioxide which forms into bubbles in the food.  When heated, these bubbles then expand and help to rise or lighten the final product.

Baking powder is a mixture of baking soda and an acid, in powdered form, that combine in liquid to create the same reaction.  There are three general types of baking powder -- fast-acting, slow-acting and double-acting; the most commonly available being double-acting.

Double-acting baking powder uses two different acids, one of which reacts at room temperature and the other only during the baking, at higher temperatures.  The first reaction helps to form the initial bubbles that are trapped in the batter.  As the food cooks, the material around these bubbles starts to set.  Carbon dioxide from the second reaction is better trapped within the bubbles and gives a better lift.

Fast-acting baking powder uses only an acid that reacts immediately, while slow-acting contains only the acid that reacts under heat.  All three forms will also contain some cornstarch to help keep the mixture dry before use.

Recipes that call for both baking powder and baking soda usually also contain an acid ingredient that will react with the baking soda.  The ingredient might be vinegar or buttermilk, mentioned earlier, or molasses, lemon juice, sour cream, honey or chocolate, to name a few.  In this case, the amount of baking soda is however much will react with the acidic ingredient.  Additional leavening is provided by the baking powder.

Baking soda, combined with an equal measure of cornstarch and twice as much cream of tartar, can be used to replace baking powder.  Use about one quarter the amount of baking soda as the recipe calls for baking powder, and then scale the cornstarch and cream of tartar accordingly.  For example, if the recipe calls for 1 teaspoon of baking powder, it can be replaced by ¼ teaspoon of baking soda, ¼ teaspoon of cornstarch and ½ teaspoon of cream of tartar.

Generally speaking, baking powder can not be substituted for baking soda since this will leave excess acidic compounds in the food which may affect flavor, texture and color.

For more on this topic, see my posting Baking Soda vs. Baking Powder Redux.

For readers who might be interested, the chemicals commonly used in baking powder, along with the bicarbonate of soda, are cream of tartar (KHC₄H₄O₆), tartaric acid (H₂C₄H₄O₆) or monocalcium phosphate monohydrate (Ca(H₂PO₄)₂ • H₂O) for the fast acting acid.   For the delayed reaction, the chemical may be sodium aluminum sulfate (Na₂SO₄ • Al₂(SO₄)₃) or anhydrous monocalcium phosphate (Ca(H₂PO₄)₂).

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Comments

[Valerie Lehman]

Can cream of tartar be used as a substitute for tartaric acid?

[Dana]

When using soda as a substitute for baking powder, must I mix the soda, cornstarch, and cream of tartar together separately before adding to the overall mixture?

[Serena]

You do not have to mix the soda, cornstarch and cream of tartar separately - just be sure to either sift or whisk thoroughly with the flour (dry ingredients).

[lora]

is there anything you can substitute for baking soda?

[tmast]

no you can not sub anything for soda :<

[Alanna]

I recently came across your blog and have been reading along. I thought I would leave my first comment. I don't know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.

Alanna

[Corrie]

What do I do if I accidentally added the amount of baking soda that was supposed to be added as baking powder? I don't have any more cocoa to be able to remake the cake! I added 1.5 tsp of baking soda and it was supposed to be 1.5 tsp of powder. Ugh!

[David Burger]

I just did the same thing for biscuits. The end result was a very bitter taste. I suggest you buy and add the cornstarch and cream of tartar as described above.

[Anali]

Wonderful article! Thank you for pointing me towards it. I think this is inspiring a blog post... ; )

[a curtis]

What on earth. Here is my internet journey, seeking the answer to "Baking soda vs. baking powder."

1. BAKING POWDER CAN REPLACE BAKING SODA
2. BAKING POWDER CANT REPLACE BAKING SODA
3. BAKING POWDER CAN’T REPLACE BAKING SODA AND VICE VERSA.

excerpts:
"You can substitute baking powder in place of baking soda (you'll need more baking powder and it may affect the taste), but you can't use baking soda when a recipe calls for baking powder."
http://chemistry.about.com/cs/foodchemistry/f/blbaking.htm

"In recipes calling for baking powder, baking soda can be used, along with some cornstarch and cream of tartar. Baking powder cannot, however, be used to replace baking soda."
http://kitchensavvy.typepad.com/journal/2005/01/baking_soda_vs_.html

“While you can't swap baking soda for baking powder, or vice versa…”
http://www.asianonlinerecipes.com/food_articles/baking-soda-baking-powder.php

So which one is it? If baking is all about accuracy, then why is it that I constantly find conflicting information, all from experts, and recipes are so often wrong? How does anything ever get baked and turn out edible, if everyone has so many different opinions? I am starting to believe that bakers are actually other-worldly beings that are unknowingly just manipulating ingredients with their minds.

[Dawn]

Do I add baking soda to make an omelette fluffly?

[Lil]

I just did a similar experiment. baking soda can replace baking powder if used properly but not the other way around

[Patty J]

Help! I just mixed baking powder into a cookie recipe that called for baking soda. Have I just ruined this entire batch of special cookies?

[Chris]

Is baking soda the bicarbonate of soda you buy from the baking aisle in supermarkets?