In a large bowl or the bowl of a stand mixer, dissolve the yeast in warm water with a pinch of sugar. When the yeast is bubbly and foamy, add the sugar, salt, oil, and 4 cups flour, and mix until smooth.
Add remaining flour, ½ cup at a time, to form a soft, smooth dough. The dough should stick just slightly to your finger when touched, but not be overly sticky. Knead for 5-7 minutes, until smooth, then roll into a ball.
Place the dough in an oiled bowl, turn over once to coat the top with oil, and cover with plastic wrap. Let rise for one hour, or until doubled. When the dough has risen, punch it down gently and divide it in half.
Place the dough, seam side down, into lightly greased bread pans, and cover with plastic wrap. Let rise for one hour, or until the dough is ½ – 1 inch higher than the top of the pan.
Preheat the oven to 375°F. Bake for 30-35 minutes or until the loaves are golden brown and sound hollow when tapped. Brush with melted butter, if desired. Remove to a cooling rack and cool before slicing. MAKES 2 LOAVES.