Professional winemakers and savvy consumers are catching on to the Clef du Vin, or “wine key”—a metal dipping stick that comes in pocket, bottle and glass sizes and which simulates the effects of the passage of time on wine. Immerse the end of the Clef du Vin into a glass of wine, and the wine’s flavor will change as if it had been aged one, two or even 10 years longer—thereby enabling the taster to assess the cellaring potential of the wine in an instant, a capability that has made the Clef du Vin the hottest (and snobbiest) accessory on the tasting circuit.