Remove the barm from the refrigerator and measure it out 1 hour before making the firm starter to take off the chill. To do this, dip a 2/3 measuring cup into a bowl of water, then scoop it into the barm to fill (the wet cup will allow the barm to slide out easily). Transfer to a small bowl, cover with a towel or plastic wrap, and allow it to warm up for 1 hour.

Add the flour to the bowl and mix together the barm and the flour, adding only enough additional flour so that you can knead this into a small ball, about the texture of french bread dough. You do not need to work this very long, just until all the flour is hydrated and the barm is evenly distributed. Lightly oil a small or mist the inside of a plastic bag with spray oil, and place the starter in the bowl or bag, turning to coat it with oil. Cover the bowl or seal the bag.

Ferment at room temperature for approximately 4 hours, or until starter has at least doubled in size. If it takes more time than 4 hours, give it additional time, checking every hour or so. Then put it into the refrigerator overnight.

Remove the starter from the refrigerator 1 hour before making the dough. Cut into about 10 small pieces with a pasty scraper or serrated knife. Mist with spray oil, cover with a towel or plastic wrap and let sit for 1 hour to take off the chill.

To make the dough, stir together the flour and salt in a 4 quart mixing bowl (or in the bowl of an electric mixer). Add the starter pieces and enough water to bring everything together into a ball as you stir with a large metal spoon (or mix on low speed with the paddle attachment).

Sprinkle the counter with flour, transfer the dough to the counter, and knead by hand for 12-15 minutes (or mix with the dough hook for 4 minutes on medium low speed, allow the dough to rest for 5-10 minutes, and then mix for 4 minutes). Adjust the water or flour as needed. The dough should be firm but tacky, like firm french bread dough. It would pass the window pane test and register 77°F to 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 3-4 hours, or until the dough has nearly doubled in size.

Gently remove the dough from the bowl and divide into 2 equal pieces (about 22 each), or divide into smaller pieces if you are making rolls, being careful to degas the dough as little as possible. Gently shape the dough into boules, batards, or bagettes.

Proof the dough in bannetons or proofing bowls on couches, or on parchment lined sheet pans that have been dusted with semolina flour or cornmeal. Regardless of the method, mist the exposed part of the dough with spray oil and loosely cover the dough with a towel or plastic wrap, or slip the pans into food-grade plastic bag. At this point you can either proof the loaves for 2-3 hours, or retard overnight in the refrigerator. If retarding, remove them from the refrigerator approximately 4 hours before you plan to bake them.

Prepare the over for hearth baking making sure to have a steam pan in place. Preheat the oven to 500°F. Carefully remove the towel or plastic wrap from the dough, or slip the pan from the bag, 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 from the top of the dough for dough proofed in a bowl. (If the dough was proofed on a sheet pan, it can be baked directly on that pan.) Score the dough. Slide the dough onto a baking stone (or bake directly on the sheet pan). Pour one cup hot water into the steam pan and close the door. After 30 seconds, spray the oven walls with water and close the door. Repeat twice more at 30 second intervals. After the final spray, lower the over setting to 450°F and bake for 10 minutes. Rotate the loaves 180° if necessary for even baking and continue baking for another 10 - 20 minutes, or until the loaves are done. They should register 205°F in the center, be a rich golden brown all over and sound hollow when thumped on the bottom.

Transfer the finished loaves to a rack and cool for at least 45 minutes before slicing or serving.