Diageo's Sterling Vineyards in California's Napa Valley is a much more likely target for Treasury Wine Estates, because it is at the luxury end of the wine category. Treasury Wine Estates, owner of Penfolds, Wolf Blass and Rosemount, may look closely at buying the Sterling Vineyards wine brand in California but is likely to steer clear of other lower-end brands that British alcoholic drinks giant Diageo is putting up for sale.