What is cold retard?

A long, slow rise in the refrigerator (usually 12-72 hours). Slows fermentation dramatically — yeast activity drops by half for every ~18°F / 10°C cooler — while the bacterial side of a sourdough or pre-ferment continues to develop flavor at its own slower pace. The net effect: deeper sourness, more complex aromatics, and a more open crumb structure than the same dough fermented in one warm stretch. Cold retarding also has practical benefits beyond flavor. It splits a long bread project across two days, firms the dough enough to score cleanly, and lets cold-start oven techniques work without overproofing in the warm-up window. Cold-retarded doughs go into the oven straight from the fridge — no warming required.