Retarding

Retarding is a bread baking technique in which dough is placed into a dough retarder, a refrigerator, or another cold environment at some point during fermentation, to slow the activity of the yeast. The resulting slower, longer rise produces a more varied mix of fermentation products and more complex flavor than a rise at room temperature. In sourdough baking, the cold also slows wild yeast more than it slows the bacteria living alongside it, so bacteria that produce flavoring compounds such as lactic acid and acetic acid have relatively more influence, which can make for a more sour loaf.