01 - Dissolve sugar in warm water in a large bowl. Sprinkle yeast over the surface and let stand 5-10 minutes until foamy.
02 - Stir salt and oil into the yeast mixture. Gradually add flour, one cup at a time, mixing until a soft dough forms that pulls away from bowl sides.
03 - Turn dough onto a lightly floured surface and knead for 6-8 minutes until smooth and elastic.
04 - Place dough in a lightly greased bowl, cover, and let rise in a warm place until doubled, about 1 hour.
05 - Punch down dough and divide in half. Shape each half into a loaf and place in two greased 9x5-inch loaf pans.
06 - Cover pans and let rise until dough extends about 1 inch above the rim, about 30-45 minutes.
07 - Preheat oven to 350°F.
08 - Bake loaves for 25-30 minutes until golden brown and loaves sound hollow when tapped.
09 - Brush tops with melted butter if desired for softer crust. Remove from pans and cool on wire rack before slicing.