Procedures

1. 1

   Stir together flours, Parmigiano-Reggiano, thyme, kosher salt, and yeast in a large, non-reactive bowl. Add tomato juice and stir until liquid is thoroughly incorporated and the mixture forms a loose, shaggy ball. The dough should be very sticky and wet; add more tomato juice or a little water if too dry.

2. 2

   Coat the sides of the bowl with olive oil to prevent dough from sticking and cover the bowl with plastic wrap. Let rise for 12 to 24 hours in a warm, draft-free environment such as a cool oven.

3. 3

   Turn dough out onto a floured countertop. Fold in half several times, dust with flour, cover with plastic wrap, and let rest for 20 minutes.

4. 4

   Fold dough in half repeatedly until it develops significant surface tension. Tuck corners in to form a ball. Place seam-side-down on a floured cotton towel, dust with flour, and fold sides of towel up and over to cover. Let rest for at least 1 hour or preferably 2 hours.

5. 5

   Line an oven rack with a pizza stone or unglazed quarry tiles and heat oven to 500°F, using convection heat if possible. When oven is almost fully heated, fill a large skillet or roasting pan with ice cubes and set aside.

6. 6

   Turn dough out onto a floured peel or cookie sheet and quickly form into desired shape with your hands or 2 dough scrapers. Use a wet knife or razor blade to cut a 1/2-inch-deep slit along the length of the loaf. Sprinkle with coarse sea salt.

7. 7

   Place pan of ice cubes one rack below pizza stone. Bake bread on pizza stone for 45 minutes. Do not open the oven during this time.

8. 8

   Remove pan from oven. Continue to bake bread until it develops a deeply caramelized crust and sounds hollow when tapped on any side, 5 to 10 minutes. Remove excess flour with a pastry brush and let cool to room temperature on an elevated rack before slicing.