I was listening to an online video (about setting up membership/subscription sites, not really appropriate for my winery readers), and one suggestion they made when researching market potential was to see how many magazines pertained to the topic at Magazines.com (a site where you can subscribe to magazines).
There are 6 results when searching for "wine": Food & Wine, The Quarterly Review of Wines, Wine Spectator, Wine Enthusiast, Wine Press Northwest, and WineMaker. Notably absent are Wines & Vines and Wine Advocate.
There are exactly zero results, however, when searching for "winery".
I'm just sayin'.