Image Number 2 for United States Patent #6478178.
An improved stopper apparatus for use with wine barrel bung holes includes a generally frusto-conical stopper member having a central aperture, a top surface, a bottom surface, and an outer circumferential surface adapted to seal against the inner circumferential surface of the bung hole. The apparatus further includes a sealing insert member having a top portion, a middle portion, and a bottom portion, the top portion having a diameter slightly greater than the stopper member central aperture such that the sealing insert member can be pushed into the central aperture so as to bring the top surface of the sealing insert member with the top surface and the stopper member during barrel aging. The sealing insert member further has a lower surface adapted for sealing engagement against the stopper member top surface during barrel fermentation. The bottom portion includes at least one flexible lateral projection element adapted to contact and apply a force against the stopper member bottom surface, so as to urge the top portion lower surface into sealing engagement with the stopper member top surface.