Place all of the potatoes, carrots and onion in the bottom of the crackpot and toss together. Sprinkle with garlic. Trim brisket of excess fat and place on top of vegetables.
Stir together the coffee, worcestershire sauce, vinegar, salt and pepper. Pour the meat in the slow cooker. Cover and cook on low for 7 to 8 hours, or on high for 4 to 5 hours.
Remove meat carefully from the slow cooker to a platter. Remove vegetables to a bowl, reserving the juices. Skim off fat and thicken the remaining juices by boiling it in a small saucepan. Serve the meat sliced with the juices spooned over top and vegetables arranged around the meat.