If I was blindfolded and you put an Old Vine Zinfandel in front of me and a non-Old Vine Zinfandel, I probably couldn’t tell the difference. So I started asking around: what separates the two, flavor-wise? Ondine Chattan, winemaker at XYZin Wines told me Old Vine Zinfandels tend to brighten the characteristics of the Zinfandel grape: producing…