Mix yeast, sugar and water in mixer with dough hook. If your yeast is good, it will "bloom" in the warm sugar water. Let it do so for a minute or two. Add 2 cups flour, and mix until smooth. Add salt. Mix. Add 2 cup flour. Mix until dough ball forms. Knead on lightly floured surface for 7 minutes, until dough is elastic. Incorporate an additional 0.5 cup flour to keep dough from sticking during this kneading. Place dough in lightly oiled large bowl, roll it in the oil to coat, and cover with towel and let rise in a draft-free warm place for 1.5 hour. Punch down the dough, and roll gently into a 20-inch long loaf. Place loaf on lightly oiled cookie sheet. Preheat oven to 400 deg F. Let dough rise, uncovered, for an additional 30 minutes. Slice three 45-degree cuts 0.25" deep with a sharp knife through the top of the loaf. Brush loaf lightly with water. Bake for 30 minutes. Let cool on rack.