Trim the brisket, removing the deckle fat and excess fat.
Season the brisket generously with the SPG (salt, pepper, garlic) rub, starting with the back side.
Cook the brisket in a smoker at 275°F until it reaches an internal temperature of 180°F, about 9 hours.
Wrap the brisket in a foil boat and continue cooking until it reaches 205°F internal temperature, about 1-2 more hours.
Allow the brisket to rest for 30-45 minutes.
Vacuum seal the brisket and place it in a 165°F water bath for an overnight rest, about 12 hours.
Remove the brisket from the water bath, slice, and serve.
