The main rising period after mixing all ingredients, where the dough ferments as one big mass before being divided and shaped.
This is the most important and most difficult stage to get right. During bulk fermentation, yeast produces CO2, bacteria produce organic acids, and enzymes break down starches and proteins. The dough should increase in size (typically 25-100% depending on your flour's protein content), develop bubbles on the surface, and smell mildly tangy. Going too short gives you dense bread; going too long turns your dough into a sticky, unworkable mess.
