Preheat grill to 375˚. Cover a sheet pan with foil or parchment. Lay salmon on top, skin side down. Season with half of the salt and pepper. Place butter cube slices on top of the salmon, top with minced garlic and lemon slices. Season with remaining salt and pepper. Pour the beer around the salmon and tightly wrap the aluminum or parchment. Make four small slits in the foil or parchment to allow steam to release.
Carefully place in the middle of the preheated grill, close the lid, and cook for 15 to 20 minutes until salmon easily flakes.
Remove from grill, and serve with lemons on top. It pairs beautifully with a garlic aioli or green goddess tarter sauce.