About baking powder and baking soda

[satimis]

Hi all,

In some recipes they call for both baking powder and baking soda. As curiosity I started googling around and found following 2 interesting documents with in-depth explanation.

1)
What Is the Difference Between Baking Soda & Baking Powder?
http://chemistry.about.com/cs/foodchemistry/f/blbaking.htm

2)
Baking Powder and Baking Soda (Bicarbonate)
http://www.joyofbaking.com/bakingsoda.html

Both baking powder and baking soda are chemical leavening agents. In another word they do the same job. As mentioned in document 2) above, "When a recipe contains baking powder and baking soda, the baking powder does most of the leavening. The baking soda is added to neutralize the acids in the recipe plus to add tenderness and some leavening .....". Is there a thumb of rule on their proportion when being added to a bread/cake recipe? Or it can only be found by extensive baking experiments? Thanks

To my understanding bread baked with baking powder/soda contains more moisture than with yeast. Any input on other difference?

B.R.
satimis

[Chocolatl]

It's softer and less chewy, more cake-like, because of the lack of gluten.

[peachez]

Shirley Corriher on Leavening.


Corriher said that too many recipes for cakes, biscuits and quick breads call for too much leavening. An overleavened cake will be heavy, or it will collapse. She recommends that each cup of flour generalyy have 1 to 1¼ teaspoons of baking powder. If using only baking soda, she recommends just ¼ teaspoon for each cup of flour. A bit more may be used in batters with heavy ingredients, such as chopped nuts or dried fruit. Also, some recipes with acidic batters, say ones with a lot of sour cream or yogurt, might also use both baking powder and baking soda, and the total will be a bit more than given above.

http://www2.journalnow.com/news/2009/jul/15/corriher-learn-some-science-in-baking-ar-160342/

[auzzi]

Shirley Corriher provides a lot of useful information for the baker and cook. It should also be stated that the exact information is relevant for US ingredients.
Baking powder varies from country to country, and the amount per cup along with the exact measurement of "1 cup" can also vary .
Bicarbonate of soda [baking soda] remains the same, but the amount varies with the size of the cup..