Dissolve yeast in 1/2 cup warm water and set aside. Sift together sugar, salt, and 5 cups flour. Combine yeast, remaining water, butter, and 2 eggs in mixing bowl and blend. Beat in flour mixture, 1 cup at a time, to make a stiff dough, adding all or a portion of the remaining flour if necessary. Cover with plastic wrap and refrigerate overnight. Next day, divide chilled dough in half, roll each out into a rope, and cut each into 12 equal pieces. Roll each piece between your palms until pencil thin. Twist into desired shapes and pinch ends together, or keep as straight rods. Combine egg yolk and milk, and brush on each piece. Sprinkle with coarse salt. Place on greased baking sheet, cover, and let rise for 45 minutes. Bake in preheated 400 degree oven 5 minutes.