Cognac is a secretive, confounding place. The people who make Cognac can be tight-lipped and evasive, and don’t like questions from outsiders. A simple tasting-room question to a producer such as, “How old are the eaux-de-vie in this blend?” might be met with a shrug and an inscrutable answer like, “Eh, a minimum of 15 years, but also some 30-and 50-yea…