Preheat oven to 350°F.
Season short ribs generously with salt and pepper. Coat your pot with canola oil and pan sear short ribs in batches. When the meat is seared to an amber brown color, transfer to a roasting pan. In the same pot, sauté carrots, onions and celery for 5 to 8 minutes then transfer to the roasting pan. Add two cans of Guinness® Draught to deglaze the pot over medium heat. Pour this liquid over the short ribs in your roasting pan.
Add beef stock, tomato juice and fresh thyme to the roasting pan and cover tightly with foil. Place meat into preheated oven and braise for 2–2.5 hours. The short ribs will slightly pull away from the bone when cooked. Ribs vary in size so cooking times may differ.
Remove short ribs from the roasting pan and transfer to a plate to rest. Strain the remaining liquid and divide in half. Pour one half of the liquid into a saucepan and reduce over medium/high heat and reduce to create a sauce.
When ready to serve, simmer short ribs in the second half of your liquid until tender, approximately 15 minutes. Spoon sauce reduction over the short ribs and serve.