Leaven

Leaven is a substance used in baking to make dough rise, resulting in light, airy bread. It works by producing gas—mainly carbon dioxide—that gets trapped in the dough’s gluten structure, causing it to expand. Common leavens include yeast, which ferments sugars to release gas; baking powder; and baking soda. The process can take from minutes to hours, depending on the type of leaven used. Leavening is essential for creating the texture and volume characteristic of many baked goods, transforming dense mixtures into soft, risen bread and pastries.