Preheat oven to 300 degrees. Sprinkle brisket with seasoned salt, pepper, and garlic. Place brisket in roasting pan, fat side up. Add onions and celery in a single layer over top of brisket, covering brisket completely. Pour chili sauce over brisket. Pour 1/4 cup water into chili sauce bottle, shake, and pour over meat. Roast uncovered 1-1/2 hours, basting every 30 minutes. Pour beer over meat. Cover tightly with foil and roast an additional 3 to 4 hours, depending on size of brisket. Remove brisket from gravy and place on a carving board. Refrigerate gravy or chill quickly by placing in freezer. When cooled, slice meat without disturbing the shape of the brisket. Slide the brisket back into pan. When gravy is cold, skim fat and pour gravy over brisket. Put back into the oven to reheat. Serve immediately. This freezes well, already sliced.