The day before making the bread, make the firm starter. In a 4 quart mixing bowl use a metal spoon to mix together the barm, flour, and enough water to form a firm ball. Sprinkle flour on the counter and transfer the dough to the counter. Knead for ~3 minutes, or until all the flour is hydrated and the ingredients are evenly distributed. Lightly oil a bowl, place the ball of dough in the bowl, and roll it around to coat it with oil. Cover the bowl with plastic wrap.

Ferment at room temperature for 4-6 hours, or until the dough doubles in size. Refrigerate overnight.

Remove the starter from the refrigerator 1 hour before making the dough. Cut the starter into about 12 small pieces with a serrated knife or pastry scraper. Cover with a towel or plastic, wrap and let sit for 1 hour to take off the chill.

This dough is too large for home mixers so knead it by hand. In a large mixing bowl, stir together the sifted whole wheat flour, salt, and starter pieces. Stirring with a large metal spoon, add at least 2 1/4 cups of the water, or enough to bring together all the ingredients into a soft ball. Adjust the flour and water as you mix as needed.

Sprinkle flour on the counter and transfer the dough to the counter. Knead the dough for 12-15 minutes, continuing to adjust the flour and water to form a supple, tacky but not sticky dough. All of the ingredients should be evenly distributed. The dough should pass the window pane test and register 77°-81°F. Lightly oil a large bowl and transfer the dough to the bowl, rolling it around to coat it with oil. Cover the bowl with plastic wrap.

Ferment at room temperature for approximately 4 hours, or until the dough nearly doubles in size.

Transfer the dough to the counter and gently form it into a large boule. Proof the dough in a banneton or prepare a proofing bowl large enough to hold the dough when it rises to nearly double its size. Place the dough, seam side up, in the banneton or bowl and mist the exposed part of the dough with spray oil. Cover with a cloth or plastic wrap.

Proof at room temperature for 2-3 hours, or until the dough grows 1.5 times in size, or retard overnight in the refrigerator. If your are retarding the dough, remove the dough from the refrigerator 4 hours before you plan to bake it.

Prepare the over for hearth baking, making sure to have an empty steam pan in place. Preheat the oven to 500°F. Carefully remove the top layer of cloth or plastic wrap from the dough 10 minutes before baking.

Generously dust a peel or the back of a sheet pan with semolina flour or cornmeal and gently transfer the dough to the peel or pan, carefully removing the cloth liner off the dough. Score the dough with a large #. Slide the dough onto a baking stone (or bake directly on the sheet pan). Pour two cups hot water into the steam pan and close the door. Immediately lower the over setting to 450°F. After 25 minutes rotate the loaf 180° if necessary for even baking lower the over temperature to 425°F. Continue to bake for another 30-40 minutes, until the dough registers 200°F in the center. The bread should be deeply browned. If the bottom seems to be getting too dark before the loaf reaches the desired temperature, place an inverted sheet pan under the bread to protect the bottom. Likewise, if the top gets too dark, tent a piece of aluminum foil over the loaf to shield it from the heat.

Transfer the bread to a rack and let cool for at least two hours before slicing or serving. Store the bread in a brown paper bag. It should be good for 5-7 days.