What the Heck Does "NV" Mean, Anyway?

"NV" stands for "non-vintage," though on the face of it, that's a ridiculous proposition. All grapes are harvested in a particular year; hence those dates on wine labels and the notion that some vintages are better than others so the wines from those years are more valuable. However, wine does not have to be made from grapes harvested all in the same ye…