Combine yeast, water, and 1 teaspoon sugar in a large bowl, stirring until dissolved. Stir in remaining sugar, salt, and 6 cups flour to form a stiff dough.
Turn dough out onto a surface sprinkled with remaining flour; knead 8 minutes or until smooth and elastic. Place dough in a greased bowl, turning to grease top. Cover and let rise in a warm place (85°), free from drafts, 1 1/2 hours or until doubled in bulk. Turn dough out onto a lightly floured surface. Cover and let rest 15 minutes. Knead 3 to 4 times.
Divide dough into 4 equal portions; roll each portion into a 13- x 7-inch rectangle. Roll up each rectangle jellyroll fashion, starting at long end. Pinch seams and ends together to seal. Place loaves, seam side down, in 4 heavily-greased baguette pans or on baking sheets.
Cut 3 or 4 diagonal slashes, 3/4-inch deep, in top of each loaf. Cover and repeat rising procedure 1 hour or until doubled in bulk. Brush loaves with egg white. Bake at 450° for 15 minutes; reduce heat to 350°, and bake 30 minutes or until loaves sound hollow when tapped. Remove bread from pans or baking sheets immediately; cool on wire racks.