Preheat the Z Grills pellet smoker to 225°F.
Place the brisket fat side down on the grill.
Cook at 225°F until brisket internal temp is 160°F.
Remove from grill and place in a deep pan lined with aluminum foil.
Pour beef stock and light beer sauce into the pan, making sure it comes up to the top of the brisket.
Take extra edges of foil and fold them over.
Use a piece of foil and cover the top.
Place it on the grill again, cook at 250°F until brisket internal temp is 200°F.
Check brisket internal temp.
Once internal temp reaches 200°F, remove from the smoker.
Rest for 10 minutes before slicing.