Leavening Agents

• Leavening is a group of additives that bakers put into breads and other baked goods. The most common leavening agents include yeast, baking powder and baking soda.

Leavened Bread

• Leavened bread includes a leavening agent. Yeast breads rely on yeast to make them rise. Quick breads, which include fruit breads like banana bread, as well as muffins, biscuits and scones, rise because they have baking powder or baking soda in them.

Yeast Breads

• In the simplest yeast breads, the baker combines flour, water, salt and yeast, kneads the dough to develop long strings of a protein called gluten in it, and then sets it aside. The yeast in the dough feeds on the sugars in the flours and produces carbon dioxide as a byproduct. The gas expands into the spaces created by the gluten, making the bread rise. When it's risen to the desired level, the baker punches the dough to release the gas, shapes the dough into loaves, puts the loaves into pans, and set them aside to rise again. Once the dough has risen to the proper height, the baker bakes the loaves.

Quick Breads

• To make a quick bread, the baker mixes the ingredients, which include either baking powder or baking soda, puts the batter into prepared pans and bakes the loaves. She deliberately combines the ingredients just enough to moisten them, because she does not want to develop gluten, which would make the bread tough.

Unleavened Breads

• Unleavened breads contain nothing to make them rise, and many examples consist only of flour, water and salt. Such breads were probably the very first breads baked, being easy to mix and bake on a hot stone set over a wood fire, or in a stone oven. You can find versions of unleavened bread in almost any part of the world, from Mexican tortillas to Indian chapattis to Jewish matzo.