Leavening

Leavening is the process of adding gas to a dough before or during baking to produce a lighter, more easily chewed bread. Most bread consumed in the West is leavened. Unleavened breads have symbolic importance in Judaism and Christianity. Jews consume unleavened bread called matzo during Passover. Roman Catholic and some Protestant Christians consume unleavened bread during the Christian liturgy when they celebrate the Eucharist, a rite derived from the narrative of the Last Supper when Jesus broke bread with his disciples, perhaps during a Passover Seder. In contrast, Orthodox Christians always use leavened bread during their liturgy.