Mix water, sourdough starter, oil, sugar, and salt together in a large bowl. Sift flour and add to the mixture. Grease or oil dough and place in an oiled bowl; cover and let rise overnight.

The next day, grease two 8 x 4-inch loaf pans. Knead dough for 10 minutes; divide in half and place into prepared pans. Allow dough to double in size.

Preheat the oven to 350 degrees F (175 degrees C).

Bake loaves in the preheated oven until top is golden brown, about 40 to 45 minutes. Carefully tip loaves out of pan onto a work surface and gently tap the bottom of loaf. If it sounds hollow, bread is done.