In a bowl or large measuring cup, combine the warm water, orange juice, honey, and yeast. Stir to mix well, then let sit for 10 minutes for the yeast to activate.
In the bowl of a stand mixer (or large mixing bowl), combine the whole wheat flour, white flour, and salt. With the paddle mixer attachment (or a large wooden spoon, if not using a stand mixer), mix the flours until just combined. Give the yeast mixture a good stir and add it to the flour mixture, continuing to stir until everything is well incorporated.
Switch to the dough hook (or dump dough out onto a well floured countertop and start kneading). Knead dough until it feels elastic and passes the windowpane test*, about 8-10 minutes. Place dough in an oiled bowl, cover with a cloth or plastic wrap, and let rise in a warm place until roughly double in size, about 1-1.5 hours.
Grease two standard loaf pans. Dust your countertop with flour and place risen dough on top of it. Using a knife or bench scraper, cut the dough into two equal pieces, shape them into loaves, and place them into your prepared pans. Cover again and let rise in a warm place for another 1.5 hours.
Preheat oven to 350 degrees. Uncover bread loaves, transfer to oven, and bake until tops of loaves are golden brown and loaves sound hollow when tapped, about 40-50 minutes. Once they are finished baking, remove loaves from their pans and cool on a wire rack before slicing and eating.