Mix the water, sugar, and yeast in a large mixing bowl. To ensure the yeast is active, check for the formation of small bubbles.
Add the salt and oil. Stir in the first 3 cups of flour. Then gradually add more flour, as needed, ½ cup at a time, until the dough begins to get thick and hard to mix. It generally takes about 5 cups of flour to get to the right consistency.
Turn the dough out onto a floured surface. Knead the dough until it is no longer sticking to your hands and is smooth and elastic, about 5 minutes.
Lightly mist the bowl with cooking spray and return the dough to the bowl. Cover with a clean dish cloth and let raise for 1 hour.
Divide the dough in half. Lightly mist 2 bread pans with cooking spray. Transfer each half of dough to each bread pan. Cover with a clean dish rag and raise another hour.
Preheat the oven to 400F during the last 10 minutes of rising time. Cook the bread 30 minutes, or until lightly golden on the top. If the top begins to brown too quickly, loosely tent with tin foil to prevent burning. Transfer the bread to a cooling rack and coat the top lightly with butter.