Once the dough has been kneaded (or not, depending on which method of kneading you are using) it is time to let the ingredients do their own thing. This crucial stage of bread making is referred to add the bulk ferment – bulk because the dough is fermented as a whole mass, prior to dividing and shaping, and ferment because of the action of the yeast and enzymes in the dough.
During the bulk ferment a lot is going on inside the dough. The process that began when the ingredients were combined, whether in an autolyse or straight into a kneading, comes into its own now. Enzymes in the dough thrive in the warm, moist atmosphere as they go about converting the starch from the flour into sugar and the protein into sugar. In a yeasted dough or a dough with a natural levain, this sugar becomes food. The yeast cells, whether commercial (such as instant dried yeast or fresh baker’s yeast) or wild (from a ‘sourdough’ starter or barm) consume the sugar in the dough and release carbon dioxide as they reproduce and expire.
The release of carbon dioxide is what creates the rise in a leavened dough, and also some of the flavour. The gluten formed by the enzymes and helped along by the kneading allows the dough to stretch and trap pockets of air. In a very high hydration dough, this results in those large, irregular holes that are common to ciabatta and sourdough loaves.
During this stage it is possible to use the stretch and fold technique to add structure and encourage a well risen bread. As explained in the previous post on kneading, this means taking a portion of the dough, stretching it and folding it back on itself, and repeating a few times for the first few hours (if using a ‘wild yeast’ levain) or a couple of times during the start of the bulk ferment.
It is important to let the dough rise in its own time, preferably at room temperature or slightly above. A longer fermentation results in more flavour. This is less important in a sweet or savory flavoured loaf where other flavours may dominate anyway. Once the dough has risen (usually to double or at least one and a half times its size, depending on the recipe) it is time to divide and shape the loaf, being careful not to knock out too much of those flavour filled, well risen gases.