Bulk fermentation — the first rise, after mixing and before shaping — is where most loaves are won or lost. The single most important idea is this: judge bulk by how much the dough has risen and how warm it is, never by a fixed number of hours from a recipe.
Open the free bake log →A recipe that says "bulk for 4 hours" was written in someone else's kitchen, with their starter and their room temperature. Fermentation speed roughly doubles for every 8–10°C of warmth. The same dough that takes 4 hours at 26°C can need 7–8 hours at 20°C, or finish dangerously early on a hot summer afternoon. The clock is a rough guide; the dough itself is the truth.
Under-fermented dough is tight and barely risen; it bakes dense, with a tight crumb and sometimes a gummy patch. Over-fermented dough is slack, sticky, full of large surface bubbles and tears when you shape it; it spreads flat and can taste sharply sour. You are aiming for the lively middle, where the dough has clearly grown but still holds tension when you tip it out.
If your kitchen is cold, warm the dough to speed bulk; if it is hot, use cooler water and watch closely so you do not blow past the window. Stretch-and-folds during the first couple of hours build the strength that lets the dough hold all that gas.
Because bulk depends on both, the most useful record pairs the percentage rise with the dough temperature and elapsed time. After a few bakes you will know your own kitchen's timing cold — and you can repeat your best loaf on purpose.
Log bulk time, temp & results — free →