The Science of Bread

Bread may seem simple, but making a light loaf depends on a series of chemical and physical changes. Most basic breads contain flour, water, yeast and salt. When flour and water are mixed, proteins in the flour form a stretchy network called gluten.

Yeast is a living microorganism. When it has warmth, moisture and food from the dough, it produces carbon dioxide gas. The gluten network traps bubbles of this gas, causing the dough to expand. This stage is often called proving or rising.

Temperature matters. If the dough is too cold, yeast works slowly. If it becomes extremely hot before baking, the yeast can die. Bakers therefore give dough time in a warm but not excessively hot place.

In the oven, gases expand and the structure of the loaf becomes firm. The surface browns and develops new flavours. By the time the bread leaves the oven, a few ordinary ingredients have been transformed into something with a very different texture and taste.