2 cups (1 pint) extra stout beer, such as Guinness®
3 tablespoons balsamic vinegar
Freshly ground black pepper
6 hamburger buns, split
13-by-9-inch heavy-gauge aluminum pan
In a small bowl combine the rub ingredients.
Press the rub into the brisket, cover with plastic wrap, and refrigerate for 2 to 4 hours.
Prepare the grill for indirect cooking over high heat (450° to 550°F).
Allow the brisket to stand at room temperature for 15 to 30 minutes before grilling. Generously brush the brisket with oil. Sear over direct heat, with the lid closed, until well browned, about 6 minutes, turning once. Transfer to a braising pan, such as a 13-by-9-inch heavy-gauge aluminum pan.
Decrease the temperature of the grill to low heat (250° to 350°F). In a medium saucepan over medium heat on the stove, melt the butter with the olive oil. Add the onion, garlic, and caraway seed and cook for 5 to 6 minutes, stirring occasionally. Add the ketchup and broth, whisk, and bring to a simmer. Add the beer and balsamic vinegar. Return to a simmer, then pour the liquid over the brisket so it comes one-half to two-thirds of the way up the sides; don’t overfill the pan. Cover with foil and grill overindirect low heat, with the lid closed, until fork tender, 3 to 4 hours, turning the brisket over twice. If using a charcoal grill, replenish the charcoal as needed to maintain a steady temperature between 250° and 350°F, adding 8 to 10 unlit briquettes after every 45 minutes to 1 hour of cooking time. Leave the lid off the grill for about 5 minutes to help the new briquettes light.
Remove the brisket from the grill. Remove the brisket from the pan and let rest for 10 to 15 minutes; reserve the cooking liquid to serve as a sauce. Cut across the grain into thin, diagonal slices. Season the sauce with salt and pepper. Serve the meat warm on a bun with the sauce.