Glass expert performed a root cause failure analysis of a broken wine bottle. The bottle had broken at the neck into three pieces (Upper left photograph). One piece still contained the cork with the cork screw still in place. In this case the cork screw was off center and had exited the cork when it was being “screwed” in. The side of the cork screw crushed the interior wall of the bottle neck, and this initiated the failure. The upper right photograph is of the re-assembled top of the bottle. In it one can see the exposed edge of the cork screw and the “crush” defect on the interior of the bottle neck. With this type of corkscrew the cork is pried out with a lever force. In this case, this force was sufficient to cause failure and injury to the person opening the bottle. With this type of cork screw, the user must be careful to center it, or he could be injured.