In a large container mix together 550 grams of bread flour with 396 grams of water at 80° to 82° and .5 grams of yeast until combined. Cover and let sit at room temperature for 10 to 24 hours or until tripled in size.
In a separate large container mix together the remaining 150 grams of bread flour, Kamut, ivory wheat flour, salt, remaining 4 grams of yeast and remaining 484 grams of water at 100 to 102° until combined.
Add the biga to the mixture and vigorously mix it by squeezing, stretching and folding until completely mixed in, about 3 to 4 minutes. Cover and let rest for 20 minutes.
Fold the dough by stretching and turning it 6 to 8 times every 20 minutes for 80 minutes.
Cover and let rest for 2 more hours or until tripled in size.
Divide the dough on a clean surface dusted with flour and form 2 dough balls. Transfer each to a floured proofing basket, cover with a towel and let proof for 60 to 90 minutes.
Place 2 Dutch oven pots into an oven and preheat to 500° and let sit for 30 minutes.
Remove the pots and place the dough carefully into each Dutch oven. Cover and bake for 30 minutes, then uncover and bake for another 20 to 25 minutes or until the outside of the bread is dark brown.
Set on a cooling rack for 30 minutes.
Slice and serve.