Any time you have the chance to try biologically aged wines from the barrel you must take it.
Here the libation in question was a vino fino by Bodegas Gongora from Seville and, although not a vino fino de jerez, was very decent. It was a nice pale gold colour, not quite crystal clear and maybe a touch of brown/green to it. A delicate, yeasty nose with some nice mineral notes of campfire smoke, and a tangy zing. Not a big, juicy wine but very approachable. It was superb with some jamon de jabugo.
Even more impressive, though, was the venenciador – your man must have served well over a thousand catavinos during the evening and never a drop did he spill. Superb stuff.