A technique for building dough strength during bulk fermentation: you stretch one side of the dough up and fold it to the center, then repeat on all four sides.
Stretch and folds are the sourdough baker's workhorse technique. They strengthen gluten, redistribute temperature and fermentation activity, and help build a more even crumb. Wet your hands first, then pull one side of the dough upward until you feel resistance, and fold it to the center. Rotate 90 degrees and repeat three more times. The dough should feel tighter and hold its shape better after each set. Most bakers do 1-4 sets during the first half of bulk fermentation.
