Grape juice concentrate

[Kcwhippet]

You must be talking about Haight. I've never been very impressed with their operation or their wine. I doubt you'll find much public information about the practice of using something other than freshly crushed grapes to make wine, though I know several wineries that do such things. Kendall Jackson adds unfermented Muscat juice to their finished VS Chard to sweeten it up a bit, but you don't see it mentioned anywhere.