Speaking as a marketer, though, I understand the complexities of this choice. First, I know that many consumers don’t share this level of interest in how their wine came to be. Some may care more that a wine taste the same from one vintage to the next, and so may be more willing to accept additives or other interventions in order to achieve such consistency. That’s not truly an argument against ingredient lists, though, because these folks could ignore the lists if they chose—assuming they actually understand what all that stuff is. Relatedly, wine labels listing bentonite, isinglass, polyvinylpolypyrrolidone, and similar compounds do run risk of unnerving the public, or at least leading it somewhat astray. I saw this first hand when I worked in consumer sales at Bonny Doon Vineyard, a winery dedicated to ingredient and process disclosure. On one occasion, we sent to media samples of a red whose label stated that untoasted oak chips were used in the winemaking process. In his review, a writer remarked that the wine tasted too oaky to him, and that he’d wished we’d skipped the oak chips. These, though, had been used only to stabilize the anthocyanin during fermentation; they were in contact with the must for a short time, and did not add to the flavor profile of the finished wine. Moreover, the wine hadn’t spent much time in barrel during élevage, so I wondered whether the reviewer had mis-ascribed the grippy tannins of a young wine to something he’d read on the label. In this case, the oak chips disclosure was a ruby-red herring.
More on the wine labeling issue at Maker's Table: