Yeast - the foundation of risen baking

Yeast (Saccharomyces cerevisiae) is a single-celled fungus that serves as a leavening agent in baking. During fermentation, it converts sugars into carbon dioxide and alcohol, causing dough to rise. It comes in fresh, dried, and instant forms. Fresh yeast is dissolved in warm milk, while dried yeast can be added directly to flour. It is a rich source of B vitamins.