Cuban Water Bread

This recipe is from my mom.Makes a very crusty bread.You can substitute half of the flour amount with whole wheat flour.

In a large bowl dissolve the yeast in the warm water or potato water.Add sugar and salt and mix well.Stir in 1.75 liter of the flour.
On a well-floured surface, knead dough for 1.75 minutes, incorporating in the last liter of flour.Place dough in a greased bowl.Let rise until doubled.
Using a lightly floured board, form dough into 2 long or round loaves.Sprinkle cornmeal on greased baking sheet; place loaves on top.Slash top with a sharp knife.Cover, and let rise until almost doubled.
Brush top of loaves with cold water.Sprinkle with sesame seeds, if desired.Place in a cold oven.
Turn oven to 200 degrees ( 200 C ).Bake for 45 minutes, or until nicely browned.Brush twice during baking time with cold water.