One of the most frequently asked questions is what is the difference between baking soda and baking powder and if one could be substituted for other. So I put together this post to clarify all those questions. Hope you find it helpful.
Baking soda or sodium bicarbonate or bicarbonate of soda is chemically a salt which is made up of sodium and bicarbonate ions, which is derived from the mineral ore Nacholite. It is also called as bread soda or cooking soda.
Baking soda as the name implies is primarily used in baking as a leavening/raising agent, meaning it helps in foaming up when added to the dough or batter, which makes the baked goods to rise when biological fermentation (like using yeast) is not desirable.
Baking soda is a base and hence it needs an acid to create a chemical reaction. So for cookies, cakes and muffins, etc to rise, baking soda has to be paired with an acidic ingredient like yogurt, buttermilk, vinegar, lemon juice, cocoa, cream of tartar etc. When it reacts with one of these acidic ingredients, carbon dioxide is released, expanding the batter and thereby giving the desired texture for the baked or fried goods.
Sometimes you might experience a bitter after taste or a soapy taste in your baked goods and you will attribute it to the baking soda. Do you know why it happens? If you carefully scan the ingredients list you will most definitely find that there is one thing missing completely or not enough of it. Can you guess what ingredient it is? It's the acidic ingredient. Without an acidic component baking soda cannot have the intended chemical reaction.
Heat will cause the baking soda to react but only half the carbon dioxide will be released. Without an acidic ingredient, a strongly alkaline sodium carbonate is produced thereby giving a bitter taste to the baked goods.
About 1/4 teaspoon of baking soda for a cup of flour should be good.
Mix it with vinegar and if it bubbles you are good to go.
Baking powder is also a dry chemical leavening agent which is made up of sodium bicarbonate (yes, baking soda), a weak acid (like cream of tartar) and starch, mostly cornstarch to improve the consistency.
Most baking powders available in the market today are double acting, meaning, leavening occurs in two stages, once when it comes into contact with a wet ingredient and once when the batter is heated.
Like baking soda, baking powder also works by releasing carbon dioxide into the batter or dough, by foaming up and causing bubbles, expanding the batter and thereby leavening the mixture, when yeast cannot be used because its flavor is not desirable in all baked goods.
Baking soda reacts as soon as it comes in contact with the acidic ingredient (lemon juice, vinegar etc) and carbon dioxide is formed instantaneously and it's critical that the batter has to be baked immediately before the gas escapes. That's when baking powder comes into picture because we have the option of delaying the gas producing reaction. The batter doesn't have to be baked immediately.
Baking powder is mostly used in recipes that doesn't call for an additional acidic ingredient because it already contains the acid component. So when you want to raise your batter/dough and are not using any acidic ingredient, baking powder should be the best option.
1 teaspoon of baking powder for a cup of flour should be good enough.
Add baking powder to a bowl filled with water and if it foams up, it's good to use.
If the carbon dioxide created by the acidic ingredient and baking soda is not strong enough for the baked goods to rise, baking powder is also used to give the necessary lift because adding more baking soda will make the end product taste bitter/metallic. You don't want that right?
I know it's a lot of information to process. None of it actually matters if you are just going to follow a tested recipe as it is. These subtle differences and theories come into picture only when you are trying to develop your own recipe. Even then it's going to be a trial and error process because there are so many other factors which influence the end result of the baked good.
I think I will have to put this in bold letters. Just because it has the same prefix "baking" and both are leavening agents they cannot be used interchangeably, at least most of the time. There will be a noticeable difference in the taste and texture of the baked goods. Although I have seen comments in some of my recipes where the readers have mentioned that using one instead of the other has worked for them. Maybe they just got lucky. I have not tried it personally.
But theoretically speaking to substitute baking soda with baking powder, you may have to increase the quantity of baking powder at least 3 to 4 times to get the same amount of leavening and of course there will be a difference in the taste of texture. Similarly to substitute baking soda for baking powder you will have to increase the acidic ingredient in the recipe and reduce the quantity of baking soda by 3-4 times, which most probably will affect the taste and texture.