What benefit does adding sugar provide to bread dough?

Adding sugar to bread dough primarily enhances the yeast's fermentation process. When sugar is introduced, it provides a readily accessible source of energy for the yeast, which is essential for fermentation. Yeast consumes the sugar and produces carbon dioxide and alcohol as by-products. This carbon dioxide gas gets trapped in the dough, causing it to rise and develop a light, airy structure.

While sugar can have other effects, such as potentially contributing to the browning of the crust through caramelization, its most significant role in bread-making is to boost the yeast’s activity. This increased fermentation results in better leavening, which is crucial for achieving the desired texture in the final bread product.

Other options may have their own merits, but the primary function of sugar in this context is as a fermentable substrate for yeast, leading to enhanced rising and flavor development in the dough.