yeast@ingredients.ca

A bit of description about a very important ingredient in making leavened flatbreads... In reading it, one can relish the mix of gastronomy and science.

Yeast is a wonderfully mysterious thing. The yeast we rely upon for baking leavens our bread and lends its appetizing smell and taste. As a single-celled fungus, yeast works in bread by feeding first upon the sugars in the dough, and later upon the maltose produced as starch granules are broken down by malt enzymes. As the yeast metabolizes the sugars, it produces carbon dioxide and alcohol, a process in bread making referred to as fermentation.

From Jeffrey Alford and Naomi Duguid, Flatbreads and Flavors: A Baker's Atlas.