What's a Unicorn Wine?

If you pay any attention to sommeliers and winemakers on Twitter, you will have noticed increasing postings over the past couple of years about something called "unicorn wines."

Here, a picture of Mouton 1928 from New York's NoMad sommelier Thomas Pasturnak, with the caption, "truly special and a legit #unicornwine." Here, a picture of Darting Pinot Meunier Pfalz Trocken 2010 from San Francisco's Acquarello sommelier Davis Smith, with the caption, "Now THIS is a #Unicornwine. And it's delicious."

What, you ask, unites these wines? The name "unicorn" has some obvious mythological connotations, and it might be easy to simply assume that these wines must be prized and hard to find. But who better to ask than the sommeliers themselves? On March 1, Michael Mina wine director Rajat Parr offered this explanation on Twitter, "A wine that is 'rare,' 'not seen much' 'special bottlings.' Not always the most expensive but just hard to find."

In early August, an attempt to establish a true set of rules for unicorn wines began on Twitter under the hashtags #unicornrules and #unicornwinerules. (For the Twitter uninitiated, hashtags, denoted by the # character, are a way of labeling the post for search results.) The results were as follows:

• The wine must have a production of fewer than 200 cases. (@RN74, Raj Parr, Aug. 5)

• "You feel genuinely uncomfortable when opening because it may never happen again." (@ChadZeigler, RN74 sommelier Chad Zeigler, Aug. 5)

• "There is no price limit." (@RN74, Raj Parr, Aug. 5)

• "The winemaker is no longer with us or retired." (@RN74, Raj Parr, Aug. 6)

• "The wine can't be on Wine Searcher [wine-searcher.com]." (@corkhoarder, Grand Cru Select's Bryan Garcia, Aug. 7)

• "If you have to ask, it ain't Unicorn." (@leviopenswine, writer Levi Dalton, Aug. 5)

A wine doesn't have to fulfill all these criteria. For example, it was questioned whether old bottlings from Burgundy producer Henri Jayer would qualify, seeing as the case production for the wines run higher than 200. However, since Jayer passed away in 2006, the verdict from Raj Parr is that these wines are indeed "unicorns." The same with wines from retired Rhône producer Raymond Trollat.

Other bottles that have been put up for consideration:

Gentaz-Dervieux Côte-Rôtie Côte Brune 1985

Monier-Perréol Saint-Joseph Laliefine 2011

Jacques-Frédéric Mugnier Nuits-St.-Georges Clos de la Maréchale 2010 (The Chardonnay)

So there you go: a working definition for "unicorn wines." Do you have any other criteria that should be added? Or have you experienced drinking your own "unicorn" wines.