In a bowl, mix the first 7 ingredients. Place roast in a 5- or 6-qt. slow cooker. Pour pepperoncini mixture over top. Cook, covered, on low 8-10 hours or until meat is tender., Remove roast; cool slightly. Skim fat from cooking juices. Shred beef with 2 forks. Return beef and cooking juices to slow cooker; heat through. Serve on rolls. To make ahead: In a large freezer container, combine the first 7 ingredients. Add roast; cover container and freeze. To use, place filled container in refrigerator 48 hours or until roast is completely thawed. Cook and serve as directed.