If asked to picture an award-winning vineyard, your mind may well wander to a traditional wine-growing region such as Rioja in Spain, Napa Valley in California, Tuscany in Italy or Burgundy in France. It seems unlikely that you would begin with the sweeping plains and granite hills of Texas, but that may be about to change. The past few decades have seen an explosion in the Lone Star State’s wine production, with the number of Texan wineries soaring from around 20 in the 1980s to roughly 450 today, according to industry body Texas Wine Growers. This has been coupled with...