While perusing Michel Suas's "Advanced Bread and Pastry" for cookies, I noticed that some cookies used baking soda for leavening, some used baking powder and some used both. I couldn't see what determined which to use. I know that soda requires an acid, but I don't understand which ingredient(s) provide the acidity.

Here is a table of the ingredients used in three popular (with me at any rate) cookies. Will someone explain why each leaven was chosen?

Leavening vs Ingredients Among Popular Cookies

Ingredients	Chocolate Chip	Oatmeal Raisin	Peanut Butter
Ingredients	Chocolate Chip	Oatmeal Raisin	Peanut Butter
Butter	x	x	x
Sugar	x		x
Brown Sugar	x	x	x
Eggs	x	x	x
Vanilla Extract	x	x	x
Peanut Butter			x
Bread Flour	x	x	x
Baking Powder		x	x
Baking Soda	x	x
Salt	x	x	x
Chocolate Chips	x
Rolled Oats		x
Raisins		x

thanks,

gary