Abstract: The wine fermentation apparatus is for use with a fermentation vessel to control the fermentation process therein. The apparatus permits the egress of the upper floating layer and carbon dioxide gas from the fermentation vessel, provides for the ingress of a makeup fluid to minimize oxidation of the wine produced, and prevents the entrance of bacteria and air into the fermentation vessel, to avoid a detrimental effect on the anaerobic wine fermentation process proceeding therein. The apparatus is comprised of a stopper for sealingly engaging the upper neck portion of a fermentation vessel. The stopper has a pair of upwardly extending apertures therethrough for sealably receiving an egress conduit and an ingress conduit. At their lower ends, the ingress and egress conduits are in communication with the fermentation vessel. An accumulator container disposed spacially upward of the stopper, is in communication with the upper ends of the egress and ingress conduits.