Add the remaining red wine, then add the short ribs back to the pot bone side down. Then carefully add the stock, carrots, celery, dried thyme, sugar, salt and pepper, and the sachet. Make sure the sachet is submerged. Turn the heat up and bring to a simmer. Cover and put the pot in the oven.
2 cups beef stock, 2 large carrots, 3 medium celery stalks, 1 Tablespoon dried thyme, 2 Tablespoons sugar, 2 teaspoons kosher salt, 1 teaspoon black pepper