Whisk together the flours, salt, and yeast in a large bowl.
Pour in the water and stir until all combined. It should be pretty sticky. Not wet-sticky, but sticky. It'll look "shaggy" if you will.
Cover the bowl with plastic wrap, and set aside for at least 12 to 24 hours. {Don't refrigerate}
When ready to bake, preheat the oven to 450°F.
Once the oven is preheated, put your large Dutch oven in it. Let that stay in there for 30 minutes. {This scared me, but it is a-ok. Just do it}
While the oven is preheating, cover your work surface with flour. Cover it really well because this stuff is sticky. Transfer your dough to the work surface and shape the dough into a ball. Cover that with the plastic wrap and let rest while everything preheats.
Carefully, take the Dutch oven out of the oven, and put your dough ball into it. Cover it with the lid, and carefully transfer it back to the oven.
Bake for 30 minutes; then take the lid off and put it back in the oven.
Bake for 13 to 15 more minutes. Your bread should be golden and crispy looking. If you tap it, it should sound hollow.
Take it out of the Dutch oven and transfer to a cooling rack to cool completely. Enjoy!
Notes
*Make sure to use a large bowl because the dough rises in this.*Don't use regular whole wheat flour because it'll cause your bread to be really dense. If you can't find whole wheat pastry flour, use unbleached all-purpose {however then it'll be regular white bread}*You only need ½ teaspoon yeast. This is less than what is in a typical packet of yeast. This confused me, but just use ½ tsp.*Use room temperature water. It doesn't need to be hot.*You may know that salt can prevent yeast from activating, but it doesn't in this recipe. I have no idea why, but it doesn't. So just follow the directions and don't worry.