In a large bowl, whisk together the all-purpose flour, whole wheat flour, instant yeast, and salt.

Pour the water and vinegar over the top. With your nice, strong hands, stir until you have a damp, shaggy dough with no bits of dry flour. Cover and let rest at room temperature for 12 to 18 hours if your kitchen is around 70°F. The dough is ready when it's noticeably expanded and the surface is dotted with bubbles.

Lightly flour a piece of parchment paper, then turn the dough out onto the surface. It will be wet, sticky, and airy. With one hand, hold the parchment paper in place. Flour your other hand then grab one side of the dough and fold it up and over itself towards the center, as if you were trying to make the dough a slightly smaller ball. Continue to move around the edges of the dough, grabbing and folding towards the center until you've made it all the way around. Dust the top of the dough with flour, then place a clean kitchen towel over it and let rest at room temperature 1 hour, until it is 50% to doubled in size.

About half an hour into the dough's rising time, place a 5.5-quart or larger Dutch oven with the lid on it in the center of your oven and preheat the oven to 450°F. Let heat for at least 30 minutes (getting that Dutch oven SUPER HOT is going to give you the best results).

Carefully remove the pot from your oven and place near the loaf (make sure you're not setting a hot pot directly on your counter!). Uncover and, using the parchment, carefully lift the loaf and parchment together and lower them straight down into the pot.

Cover the pot and immediately transfer to the oven. Bake covered for 30 minutes. Uncover, reduce the oven to 425°F, and continue baking for another 10 to 20 minutes, until the loaf is a gorgeous golden brown. If the loaf isn't browning evenly, rotate the pan 180°F as needed.