Tip - Leavening Agents

Leavening agents The St. Petersburg Times, published October 12, 2000

Professional bakers often refer to "formulas" for breads or cakes rather than "recipes" 
because baking is a science, and a bakeshop is like a chemistry lab, where ingredients 
react to one another as they are heated.

Leavening agents play a large role in baked goods because they add volume to the finished
product.


Common leavening agents:

Yeast. This microscopic plant reacts with carbohydrates (flour and sugar) to cause 
fermentation, which releases carbon dioxide and alcohol. In baking, the alcohol evaporates, 
and the carbon dioxide adds to the volume. Yeast can be purchased in compressed cubes or
granulated in packets or jars. It also adds flavor and is more commonly used in bread 
doughs rather than cake or muffin batter.

Baking soda. This is sodium bicarbonate. When mixed with moisture (oil, water) and acid 
(honey, fruits, cocoa, molasses), carbon dioxide is produced.  Products leavened with 
baking soda must be cooked as soon as they are mixed, or the baking soda will lose its 
leavening powers. Used in cakes, muffins, cookies and quick breads.

Baking powder. Baking soda mixed with an acid becomes baking powder and does not require 
acid in the recipe to produce leavening gases. This makes powder more versatile than soda.
Single-acting baking powder requires only wet ingredients to react. Used in cakes, muffins,
cookies and quick breads. Some recipes call for both baking powder and soda.