700 gr stone-ground wheat flour
300 gr wheat flour
700 gr water 
400 gr solid mother yeast             
22 gr sea salt               
5 gr yeast


For the crusty bread: Mix the flours with the water and leave to stand for 30 minutes. Add the salt, fresh yeast and solid mother yeast. Knead to form a fine, smooth, elastic dough. Leave to stand for 2 hours 15 minutes. Transfer to the working surface and fold (close over like an envelope).Place the dough in a bowl and repeat the above operation after leaving to stand for 1 hour. After 2 hours 15 minutes, turn the dough onto the working surface and use a pasta cutter to cut into 950 gr pieces (or 480 gr, depending on the oven size). Shape the dough into balls and place on a
smooth, floured surface.  Leave to stand for 2 hours. Pre-heat the oven
to 200-220ºC. Make 4 cuts on top of the loaves and bake for 30 minutes with steam.  Remove from the oven and leave to cool for 1 hour.