Glossary

Carbon dioxide

Carbon dioxide is the gas that yeast produces when it ferments sugars, and it is what inflates bread dough. The gas collects in tiny bubbles inside the gluten network, which stretches around them like thin balloons. When the network is strong the gas stays trapped and the dough rises; when it is weak the gas escapes and the loaf turns dense. During baking the trapped gas expands further with heat, causing oven spring. The alcohol that forms alongside it mostly evaporates in the oven. See also: Fermentation, Gluten, Oven spring.