By Sasha Smith, NYC Correspondent So it came to me on Tuesday night as I was chewing on a mouthful of Vino Nobile di Montepulciano and trying to decide if I could call the tannins both “firm” and “drying”: the Diploma is to wine what dressage is to horseback riding – arcane, academic and interesting to an extremely small, and extremely passionate, group of people. This point is not lost on Mary Ewing Mulligan, (from now on, MEM for short) who reminded us that we are “operating in some never-never land” at arm’s length from the average drinker’s experience. I…