In a small bowl proof the yeast in 1/2 cup lukewarm water with 1/2 cup of the flour for 30 minutes. In a bowl combine the wine, the olive puree, the oil, the salt, the white pepper, and 1/4 cup water, stir in the yeast mixture and 2 to 2-1/2 cups of the remaining flour, and combine the dough well. Knead the dough on a well floured surface, incorporating more of the remaining flour as necessary to keep it from sticking, for 15 minutes. Put the dough in a well buttered bowl, turn it to coat it with the butter and let it rise, covered with plastic wrap, in a warm place for 1 hour, or until it is double in bulk. Punch down the dough, form it into an oval, about 8 inches long, and put it on a well buttered baking sheet. Score the top of the bread diagonally with a sharp knife at 1 inch intervals and let the bread rise in a warm place for 30 to 40 minutes, or until it is almost double in bulk. Bake the bread in a preheated 375 degree oven for 35 to 45 minutes, or until it is golden and sounds hollow when tapped, transfer it to a rack, and let it cool. 1 loaf.