I only ever fold dough that I’m mixing by hand. Due to minimal mixing and no kneading, hand-mixed doughs need to be strengthened. Folding does this by physically helping alongthe gluten formation.

To fold the dough: Keeping the dough in the bowl, gently lift and pull it toward you, and fold it over itself. At first, it will pull very easily and stay where you leave it. Rotate the bowl a quarter turn and fold it again, then give the bowl another quarter turn and fold it again. After four or five turns and folds, it will be as tight as it needs to be and the dough will resist being folded any more. That’s when you know it’s time to stop. I fold the dough twice during the first 1 ½ hours of fermentation (once after 45 minutes and again at 90 minutes).

After that, I like to leave the dough alone to ferment and let all the lovely flavorful gases build up undisturbed. Folding also gives you a good opportunity to check on your dough. As bulk fermentation progresses, you should start to see it come alive, with a few air bubbles.