In a cup, dissolve yeast in 1/2 cup warm water; set aside. In a large bowl, combine hot water, sugar, salt, oil and 3 cups flour; stir well. Stir in yeast mixture. Add remaining flour and stir well with a heavy spoon. Leave spoon in the dough; allow dough to rest 10 minutes. Stir; let dough rest another 10 minutes. Repeat this process 3 more times, making 5 times in all. Turn dough onto a lightly floured board. Knead just enough to coat dough with flour; divide dough into 5 equal balls. Roll out each ball into a 5-inch by 8-inch rectangle; roll up lengthwise, pinching together seams. Pinch and form ends to resemble the end of a bone. Place loaves seam-side down on 2 greased baking sheets, allowing room for both to rise. Cover; let rise in a warm place for 30 minutes, or until double in bulk. Brush with egg white. Bake at 400 degrees for about 30 minutes, or until crusty and golden. Remove to wire racks to cool.