Explain why bread rises during baking in the oven?

First reason: The yeast

Yeast is a unicellular microorganism that has been used for millennia to leaven bread dough. When rehydrated and fed with sugars present in the flour, yeast starts to ferment. This fermentation process produces carbon dioxide (CO2), which accumulates in the dough and creates air bubbles.

These air bubbles are trapped by the gluten network formed by the mixture of flour and water. When the dough is heated in the oven, the CO2 gas expands due to the heat. This creates internal pressure that pushes the dough walls outward, allowing the dough to rise and swell.

Thanks to the action of yeast, bread acquires its characteristic airy texture and alveolar crumb. Yeast also brings specific aromas and flavors to bread, contributing to its delicious taste. In short, yeast plays an essential role in the bread-making process and its ability to rise during baking.

Second reason: Fermentation

Fermentation is a key process in bread making. When the bread dough rests, microorganisms such as yeast and bacteria feed on the sugars present in the flour. These microorganisms then produce carbon dioxide (CO2) and ethyl alcohol. The CO2 trapped in the dough forms bubbles that accumulate, causing the dough to rise. This is what gives bread its airy and fluffy appearance.

During fermentation, yeast also transforms sugars into alcohol and other aromatic compounds. These chemical reactions contribute to the development of the characteristic flavors of bread. The duration and conditions of fermentation can be adjusted to influence the final taste of the bread.

Fermentation also helps make the nutrients in the flour more accessible and digestible. The microorganisms in the dough break down the complex components of the flour, making it easier for the body to absorb them during digestion. This enhances the nutritional value of bread by releasing minerals and vitamins present in the flour.

In summary, fermentation is an essential process in bread making because it allows for the production of CO2 responsible for dough rising, influences the taste of bread, and improves its digestibility by releasing the nutrients in the flour.

Third reason: The heat of the oven

When bread is placed in a hot oven, the heat triggers a series of physical and chemical reactions that contribute to its baking and rising. Indeed, the heat of the oven has a significant impact on the bread dough, allowing the rising process to continue and finalize.

Firstly, the heat of the oven causes the water present in the bread dough to evaporate. This evaporation creates steam that accumulates inside the dough, increasing the internal pressure. This increased pressure contributes to the expansion of the dough, resulting in the bread rising during baking.

Next, the heat of the oven activates the yeast present in the dough. Yeast, microorganisms responsible for fermentation, react to the heat by producing carbon dioxide. This gas accumulates inside the dough, forming small bubbles that give the bread its airy texture and holey crumb.

Finally, the heat of the oven promotes the coagulation of proteins in the bread dough. This coagulation process strengthens the structure of the dough, allowing the bread to maintain its shape and volume during baking. The heat of the oven therefore plays an essential role in transforming bread dough into a delicious golden and fluffy loaf.