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
History of bread History of bread Bread was central to the formation of early human societies. From the western half of Asia, where wheat was domesticated, cultivation spread north and west, to Europe and North Africa. This in turn led to the formation of towns, as opposed to the nomadic lifestyle, and gave rise to more and more sophisticated forms of societal organization. Similar developments occurred in eastern Asia, centered on rice, and in the Americas with maize. Charred crumbs of a flatbread made by proto-Natufian hunter-gatherers from wild wheat, wild barley and plant roots between 14,600 and 11,600 years ago have been