The universe of Italian wine is vast — maybe, ultimately, unknowable. Over 2,000 indigenous grape varieties originated in the country, claims expert Ian D’Agata, more than Spain, France and Greece combined. (Of those, just 377 are cultivated, according to Jancis Robinson’s “Wine Grapes.”) Some, like Sangiovese and Nebbiolo, will sound familiar (at least vaguely familiar) to American wine lovers. But for every up-and-coming variety — Rossese, Lagrein, Frappato — there are dozens languishing in obscurity. Caloria, anyone? Quagliano?

Italian wine’s heterogeneity is what makes it exciting, though it may also explain why its neighbor to the west is more often represented on top U.S. wine lists, even those that look beyond the big names in Bordeaux, Burgundy and the Rhone. Whereas it’s easy today to find restaurants with specialties in French regions like the Loire Valley or the Jura, it’s still the rare sommelier who stakes a special claim in Italy’s Friuli or Valle d’Aosta.