A ferment is a fermentation starter used in indirect methods of bread making. It may also be called mother dough.
A ferment and a longer fermentation in the bread-making process have several benefits: there is more time for yeast, enzyme and, if sourdough, bacterial actions on the starch and proteins in the dough; this in turn improves the keeping time of the baked bread, and it creates greater complexities of flavor. Though ferments have declined in popularity as direct additions of yeast in bread recipes have streamlined the process on a commercial level, ferments of various forms are widely used in artisanal bread recipes and formulas.