title_body: What is the largest winery that supplies sacramental wine to the Catholic Church?
upvoted_answer: The nation's largest producer, the Mont La Salle Altar Wine Company in the Napa Valley of California, makes a rose of petite sirah, zinfandel, ruby cabernet and cabernet sauvignon.
  
  
  From the NY Times: Sacramental Wine, Lowest Profile of All
  
  Mont La Salle Altar Wines website
  
  I love the screw cap!