Preheat the smoker to 250 degrees with the lid closed. Prepare the meat while the smoker is heating.
Place a heat-safe bowl of bourbon or apple cider vinegar inside the smoker - off to the side so it is out of the way.
If your butcher hasn’t already - begin by trimming any excess fat and silver skin from the roast. Place on a tray lined with foil for seasoning.
Rub the butter or tallow all over the outside of the roast.
In a small bowl, combine the rub ingredients - coffee grounds, granulated garlic, coarse salt, onion powder, black pepper, and chili powder. Stir.
Liberally add the rub to the roast, patting it down onto the butter.
Place the roast on the preheated smoker. If you just lift it by the foil and set it along with the foil on the smoker - this is the easiest way. Be sure to leave the foil open for now - do not wrap.
Close the lid and let it smoke until it reaches 165 degrees internal temperature. You should have a beautiful bark that has formed on the outside. This should take about 3-4 hours.
Once the roast has reached 165 degrees inside, pull the sides of the foil around the roast to cover it. You may need to add another piece on top to completely cover it. You don’t want any steam or heat escaping at this point. Do this carefully as it will be quite hot. Leave the temperature probe sticking out of the foil.
Cook until the temperature reaches 205 degrees - approximately another 2 hours.
Remove from the smother and unwrap the roast. Gently tent it with foil and let it rest for another 30 minutes before slicing and serving.