Nebbiolo is the grape variety behind the top-quality red wines of Piedmont, northwestern Italy, the most notable of which are Barolo and Barbaresco. Nebbiolo wines are distinguished by their strong tannins, high acidity and distinctive scent -- often described as "tar and roses". A less obvious characteristic, visible only over time, is their tendency to lose color. Within just a few years of vintage, most Nebbiolo wines begin fading from deep, violet-tinged ruby to a beautiful brick orange.