For the Biga: Stir the yeast in warm water to dissolve. Sprinkle sugar over the mix and let sit for 5 minutes, if yeast is foamy it is active.
Mix yeast with flour until all flour is incorporated, no dry clumps. Cover and let rise in a warm draft free place for 6 hours. Refrigerate overnight.
For Bread: Stir the yeast in warm water to dissolve. Sprinkle sugar over the mix and let sit for 5 minutes.
In bowl of stand mixer with hook attachment mix yeast, biga, 3 cups of the flour and salt on low speed for one minute. Scrape down sides and mix on medium, add remaining flour 1 cup at a time, mix and scrape down before adding more flour. Dough should be sticky but smooth, you may not need all the flour.
Put dough in a greased bowl (I just spray the bowl with cooking spray) turning to grease the top. Cover and rise in a warm, draft free area for 30 minutes. Punch the dough down, recover and let rise another 1 hour.
Punch dough down and divide in half. Roll each half into a large rectangle , then roll tightly, from the long side, tapering the ends. Place the loaves on a greased baking sheet, cover and let rise 1 hour or until doubled in bulk.
When the dough has about 30 minutes left, preheat the oven to 350 deg. F and place a dish of hot water on the bottom rack.
With a sharp knife cut diagonally 3-4 times across the tops of the loaves. Spritz the top of the loaves with water, either from a spray bottle or just wet your fingertips and flick the water at the loaves. Bake for 30 minutes at 350, then lower the oven temperature to 300 deg. and bake an additional 30 to 45 minutes. Bread will be browned on top when done and sound hollow when you knock on it.