Mix together the flour, salt and yeast in a medium mixing bowl. Add the cool water and mix everything together until it is a sticky glob. If it’s not very sticky, add a couple of tablespoons of water and mix until it’s very sticky.
Loosely cover the bowl with plastic wrap and let it sit at room temperature for 12-24 hours or until doubled in size.
When the dough is dotted with bubbles and risen, carefully remove it from the bowl onto a floured surface. Lift and fold the edges of the pancake in to make a ball with the seam on top.
Dust a cotton towel generously with flour or bran and place the ball of dough in the towel, seam side down. Dust the top of the ball with flour or bran. Fold the towel over the ball so it is covered and let sit again for 1-2 hours until doubled in size.
About half an hour before the bread has risen, heat the oven to 475 degrees f. Place a ~5 quart cast iron pot, with the lid on, in the oven while heating. (Remember to remove any plastic or melt-able parts.)
Use potholders to remove the hot pot and open the lid. Invert the ball of dough from the towel gently into the iron pot so the seam side is up again. It will look like an unsightly blob, but that’s ok. It will even out as it bakes.
Cover the pot, throw it back in the oven for 30 minutes. Remove the lid and bake for another 15-30 minutes until deep brown but not burned.
Carefully remove loaf of bread from the pot and cool on a rack for at least one hour. The bread will pop and crackle as it cools and should have a thin, crispy crust.