In Italy, rustic bread is seriously crusty, with a toothsome crumb and a clean, strong flavor. The most traditional loaf is shaped like a torpedo and contains just four ingredients—flour, water, yeast, and salt. This recipe relies on a biga (flour, water, and a little yeast) for flavor. Since the biga must ferment for 6 to 27 hours, this recipe is best made over two days. Once the biga has fallen, the remaining flour, water, and yeast are added, along with the salt. As the dough rises, it is folded (or turned) twice to build structure. The dough is shaped and baked on parchment paper for easy handling. You will need a baking stone as well as a water bottle to mist the dough with water before it goes into the oven. (The water helps promote a really thick crust.)