If you happen to wake up in the middle of the night, you can squirt or brush the roast with the BBQ/vinegar 'mop'. The brown sugar in the rub and the sugar in the sauce will start to make the outside of the roast look REALLY dark as it caramelizes. This is fine and you want that look and crustiness! We usually mop it two to three times during the night as my hubby wakes up a lot. If you don't wake up, don't worry about it, it will still be delicious and crusty.