Place flour, sugar, salt, and yeast in a bowl; mix thoroughly.  Add enough water from your first cup of water to make the dough come together.  This is a soft dough, but it should form a kneadable (not too sticky) dough.  Add more flour if necessary.  Knead the dough until the gluten chains line up: the dough will feel different; about 10-12 minutes.

Place the dough in a greased bowl, turning to coat all sides.  Cover and let rise in a warm place for about 30 minutes, or until doubled in bulk.  Dough is ready if indentation remains when touched.

Punch dough down.  On a lightly floured surface, roll into a 16"x12" rectangle.  Cut dough in half, creating two 8"x12" rectangles.  roll up each half of the dough tightly, beginning at the long side, pounding out any air bubbles as you go.  Roll gently back and forth to taper end.  Place 3" apart on a greased cookie sheet.  Make deep diagonal slashes across loaves every 2", or make one lengthwise slash on each loaf.  Cover, and let rise in a warm place for 30-40 minutes, or until doubled in bulk.

Meanwhile, preheat your oven to 375F/190C/Gas 5.  Place a bowl with the remaining 1 cup water in it in the bottom of the oven, to create steam.  This helps give a crunchy crust; omit if you prefer a soft crust.

When the dough has risen, mix egg white (for a crunchy crust, or egg yolk for a soft crust) with water; brush over tops of loaves.  Bake for 20-25 minutes in the preheated oven, or until golden brown.