Put the Flour, the yeast, the sourdough mixture, the lukewarm water and the coarse sea salt in a bowl and knead vigorously. If the water is not enough, add a little more.
Let the dough rise in a warm place for an hour.
Then beat 50 times vigorously on the work surface so that it becomes beautifully smooth and then form into a loaf.
Fill a high tray with water to the edge and leave it in while baking. The steam provides for additional crispness of the bread.
