Carbon Dioxide (CO2

Carbon Dioxide (CO2). A colorless and odorless gas produced in the dough by yeast (q.v.) when it ferments assimilable sugars. It acts as the leavening (q.v.) agent by forming minute gas cells that cause the dough to expand and become aerated, a basic requirement for achieving a soft, spongy crumb (q.v.) in yeast-fermented bakery products. It is also the gas that is released in chemically-leavened cake batters (q.v.) when baking soda (q.v.) reacts with any of the acidic materials that are present either as components of commercial baking powder (q.v.) or are added in batter formulation.