Add the yeast, sugar, water and milk to a big bowl and whisk well. Cover with a towel and let it sit for 5 minutes. The mixture should be a little "foamy" on top. If your mixture didn't foam up, then your yeast is probably expired!
Add the butter, salt and 1 cup of white flour. Use a mixer to blend it together until completely combined. Add 1 cup of wheat flour and use a spatula to mix until combined. Add the remaining flour (1/2 cup of each) and mix to incorporate it. At this point, the dough should be a shaggy ball. Not all the flour will be incorporated, but that's ok. *If doubling the recipe, Add 2 cups of flour at a time for 6 cups total.
Once mixed, place the dough onto a clean, lightly floured surface and knead it for about 4-5 minutes. (But if you have a dough hook and mixer, feel free to use that!) If you've never kneaded bread, I recommend looking up a quick video or checking out the one above. The dough will be sticky, so keep some flour nearby for your hands.
Spray a large clean bowl with cooking spray and place the dough inside. Cover it tightly with a towel, foil or saran wrap and let the dough rise for an hour (or until it doubles in size) in a warm spot. I always set my dough on the stove with the oven on at 350.
After the dough has doubled in size, punch it down (press down on the dough with your fist to collapse it) and turn it onto a lightly floured surface. With a rolling pin, roll the dough into a rectangle, about 7 inches wide and 10-12 inches long. Then roll the short side up along the long side to make a log, then place it in the bread pan. Cover and let it rise again for about an hour, until the dough has risen an inch past the rim of the pan. Preheat your oven to 350 F while it rises if you haven't already.
Bake the bread for 32-34 minutes at 350 F. It should be lightly brown on top and sound hollow when you tap it. Carefully remove the loaf from the pan and let it cool on a wire rack if you have one or on a clean towel. When it's completely cool, slice it with a serrated knife.
Storage: If you eat bread frequently, store half of the loaf on the counter in an airtight container, and half in the freezer. When your counter stash is gone, take out the frozen loaf and put it in the container.