Main Page | See live article | Alphabetical index Leavening agent A leavening agent is an organism or substance that when added to a dough of flour and water causes it to "rise" by evolving carbon dioxide or other gasses that become trapped as bubbles within the dough. Commonly used leavening agents include: baker's yeast sourdough yoghurt baking powder steam air External Links Leavening This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.