According to Groupe Charlois - the Burgundy-based producer of brands such as Saury, Leroi, Ermitage and Berthomieu - WC will operate as part of Charlois Cooperages USA.
Under the new owners, the Cloverdale-based cooperage will become a Treasury Wine Estates supplier, with joint research projects set to continue.
Up to now WC, which produces 33,000 barrels annually, has been producing French and American oak barrels for Treasury Wine Estates brands.
Fabrice Gautier, chief executive officer of Groupe Charlois said: "The exceptional opportunity presented by Winemakers Cooperage allows us to bring our vision of exceptional quality, sustainability and service to the US, building on the Charlois family history of enhancing the work of winemakers.”
Michael Kluczko, Treasury Wine Estates senior vice president supply/Americas said: “Groupe Charlois brings added insights and skills that will provide a new level of execution to the cooperage.
"We expect to work closely with Groupe Charlois so our winemakers will have even more choices to enhance the quality of our wines."
