Bread unpredictable since the steam is not produced until the bread is baked. Steam leavening happens regardless of the raising agents (baking soda, yeast, baking powder, sour dough, beaten egg white) included in the mix. The leavening agent either contains air bubbles or generates carbon dioxide. The heat vaporises the water from the inner surface of the bubbles within the dough. The steam expands and makes the bread rise. This is the main factor in the rising of bread once it has been put in the oven. CO generation, on its own, is too small to account for the rise. Heat
Bread in culture Abrahamic religions of Judaism and Christianity. During the Jewish festival of Passover, only unleavened bread is eaten, in commemoration of the flight from slavery in Egypt. The Israelites did not have enough time to allow their bread to rise, and so ate only unleavened bread matzo. In the Christian ritual of the Eucharist, bread is eaten as a sacrament either as a symbolic representation of the body of Christ or, as in the Catholic liturgy, as a real manifestation of the body of Christ. Specific aspects of the ritual itself, including the composition of the bread, vary from denomination to