Originally Posted by VitaminQ
I generally don't bother rubbing the fat cap, since it will end up rendering off or getting trimmed. That being said, it usually ends up acquiring a fair amount of rub anyway.
VQ brings something up that I think will be very important.
I personally cook with the fat cap down after a discussion here with Jim Minion. It seems to "protect" the meat from the heat (in my verticals)
But regardless of whether you are in the cap up/cap down camp, I think that, in a kettle, the cat Must be down, because of the proximity to the heat source. You want to protect that bottom from becoming shoe leather from being inches from the heat source.
Others will differ, but that is the beauty of BBQ!