Yeast in baking means baker’s yeast, Saccharomyces cerevisiae, a single-celled fungus. It is grown commercially on sugar-rich media such as molasses and sold fresh, as active dry granules or as instant yeast that can be mixed straight into flour.
In dough, yeast feeds on sugars and produces carbon dioxide along with small amounts of alcohol and aroma compounds. The gas makes the dough rise, and the by-products give bread and pastry their typical flavour. In the Today - Croissant Chocolate and Hazelnut & Vanilla Cream Filling, yeast works with steam from the dough to give a light, airy pastry around the cream. The heat of the oven kills the yeast, so no live yeast remains in the baked product.
Yeast is not one of the major allergens. Baker’s yeast is different from yeast extract, a savoury flavouring made from broken-down yeast cells.
