To make the roast: Preheat the oven to 350 degrees F (175 degrees C). Trim any thick pieces of dense, hard fat from roast, but leave smaller areas of fat in place.

Mix beef base and garlic together in a bowl. Mix thyme, oregano, peppercorns, and salt together in a separate bowl. Rub beef base mixture generously all over roast, then sprinkle with herb mixture. Place roast into a heavy-based roasting pan.

Roast in the preheated oven until meat has formed a brown crust, about 3 hours. An instant-read thermometer inserted into the thickest part of the roast should read 130 degrees F (54 degrees C) for medium-rare. Remove from the oven and let stand while you make the sauce; the temperature will rise 5 to 10 degrees F as it rests.

To make the au jus: Whisk water and beef base together in a saucepan over medium-low heat until base dissolves. Whisk in red wine, thyme, oregano, and garlic powder, then add onion, carrot, and celery. Bring to a boil, then reduce the heat and simmer, stirring frequently, until sauce reduces by about half, 20 to 30 minutes. Strain au jus and discard vegetables. Serve with roast.