Unleavened bread is bread that is made without leavening, a substance that causes expansion of the dough. Yeast or baking powder are the most comment leavening agents.
Faster to make
Unleavened bread is much faster to bake, since there is no need for the dough to rise, or proof. The process of proofing the yeast in a leavened dough normally takes a few hours for each rising.
Easier to make
Unleavened bread requires no preferment process, or testing of the yeast. Making unleavened bread consists of four steps: measuring ingredients, mixing the ingredients, kneading slightly, and baking.
Cheaper to make
Since there are so few ingredients in unleavened bread--normally only flour, oil, and water--unleavened bread costs less to make than breads requiring yeast.
Some people have developed food allergies to the yeast used in baking. Unleavened bread contains no yeast.
Although some unleavened bread recipes can contain sugar, most recipes do not. The simple ingredients of flour, oil, and water are sufficient to prepare unleavened bread.
Suitable for religious observances
Unleavened bread is acceptable in various religious ceremonies, whereas leavened bread, or bread containing yeast or baking powder, is not.