Place potatoes and celery in a 5-qt. slow cooker. Cut brisket in half. In a large skillet, brown beef in oil on all sides; transfer to slow cooker. In the same pan, saute onion until tender. Add garlic; cook 1 minute longer. Add to slow cooker., Add beer and bouillon granules to skillet, stirring to loosen browned bits from pan; pour over meat. In a large bowl, combine the remaining ingredients; add to slow cooker. , Cover and cook on low for 8-10 hours or until meat and vegetables are tender. Discard bay leaf. To serve, thinly slice across the grain.