In a large bowl or the bowl of a stand mixer, dissolve the active dry yeast in the warm water with a pinch of sugar. Let it sit until bubbly and foamy. If the yeast does not foam, start again with fresh yeast.
Add the remaining sugar, salt, oil, and 4 cups bread flour. Mix with the dough hook until combined and smooth.
Gradually add the remaining flour, ½ cup at a time, just until a soft, smooth dough forms. The dough should begin to pull away from the sides of the bowl and feel slightly tacky when touched, but it should not be wet or overly sticky. You may not need the full amount of flour.
Knead with the dough hook on medium speed for 5 to 7 minutes, until the dough is smooth and elastic. When stretched gently, a small piece should become thin enough to let light through before tearing.
Lightly grease a large bowl with oil or cooking spray. Place the dough in the bowl and turn it once to coat. Cover and let rise in a warm place for about 1 hour, or until doubled in size. Use the size of the dough as your main guide since rise time can vary depending on the temperature of your kitchen.
Gently punch down the risen dough and divide it in half. On a nonstick baking mat or lightly floured surface, roll each piece into a rectangle about 8 inches wide. Starting at the short end, roll each rectangle tightly into a loaf. Pinch the seam closed and place each loaf seam side down in a lightly greased loaf pan.
Cover the pans lightly with greased plastic wrap and let the dough rise until it reaches about ½ to 1 inch above the top of the pans. This will usually take about 1 hour, but use the height of the dough rather than the clock as your guide.
Preheat the oven to 375°F. Bake for 30 to 35 minutes, until the loaves are golden brown and sound hollow when tapped. If using an instant-read thermometer, the center of the bread should be about 190 to 200°F.
Brush the warm loaves with melted butter, if desired. Remove them from the pans and transfer to a wire rack to cool before slicing. The recipe makes 2 loaves.