Sourdough French Bread

Mix starter, water and flour. Let stand until bubbly and double in bulk. Add salt and about 4 to 5 cups flour or enough to make a stiff dough. Form into two long loaves. Place on greased cookie sheet. Brush with 1 egg white whipped with 1 tablespoon water. Sprinkle with sesame seeds if desired. Let rise until double in bulk. Brush with egg white mixture again. Bake at 375 degrees for 45 minutes or until golden brown.