(FORTUNE Magazine) – So you're at a cocktail party, and some snob is spouting off about the barnyard nose on Bordeaux wine. You wonder: Does this person really know a damn thing? At least a Wall Street Master of the Universe has a hedge fund to prove his status. But can't any poseur proclaim himself a master of wine?

As it happens, no. There's actually such a thing as a Master of Wine, and the designation is nothing to sniff at. There are only 245 people worldwide who have earned the right to use the initials MW after their names--a mere 21 in North America. The title is bestowed by the Institute of Masters of Wine, in London, generally regarded as the "preeminent institution in the world of wine," in the words of Mark deVere, Robert Mondavi's resident MW (given that there are so few, it's a point of pride for a wine company to have one).

The MW title, which requires years of study, a 32-day examination, and a dissertation, was born in 1953, when Britain's Wine and Spirit Association got together with the Worshipful Company of Vintners, a guild that dates back to the Middle Ages, and decided that it was necessary to set some standards in the business. (London has long been the center of the wine trade.) At first, only Brits who had worked in the business for five years were eligible for the MW. Then, in the 1980s, the institute opened up eligibility to non-Brits, partly because it was becoming apparent that those excluded might--horrors--devise their own version. Today the MW exam is given every June in London, Sydney, and San Francisco.

But even if you really know your wine, and you're tempted to try this, beware: It's not infrequent to hear the word "masochistic" applied to candidates for an MW. Lisa Granik, a fine-wine manager in New York City at Charmer Industries, a major distributor, is taking the exam this June. She has learned Russian, gotten a masters in international relations, passed the bar, taught law as a Fulbright Scholar in Moscow, and earned a JSD, or Doctor of the Science of Law. She says the MW is harder in some ways than the bar exam, and certainly more challenging than her doctorate. Ex-candidate Paul Wasserman, who is a wine buyer in Los Angeles and whose mother, Becky Wasserman, is a major exporter of Burgundy wines, says, "I started tasting wine at the age of 4, and I was not prepared." Wasserman dropped out (as many do) partly due to the overwhelming time commitment. "If you're not ready to have military discipline about the thing, I don't think you can pull it off," he says.

To begin with, you have to be accepted as a student, which may require a personal essay answering the question Why?, an elaborate application detailing wine regions of the world that you've visited, and even mock tasting notes. Then you study pretty much on your own for two years, during which time you must become an expert in everything from viticulture (the growing of grapes) to viniculture (the making of wine) to marketing and distribution. Jean Reilly of New York, another candidate who is taking the exam this June, can tell you all about the various manure preparations used to nurture vines. Her study group spent its last meeting grilling a viticulturist about bugs.

Naturally, you also have to learn how to taste wine in a whole new way. Not only must you be able to taste a wine blind and identify its salient characteristics--the country where it's made, the grape variety, the vintage, the quality--but you may also have to discuss such topics as the method of production, the alcohol level, the residual sugar level, and the use of oak. To prepare, students taste, taste, and taste some more--but not exactly in a way most of us would consider enjoyable. Chris Cree, who runs a wine store in Bernardsville, N.J., and earned his MW in 1996, used to leave his dozens of barely sampled bottles for his neighbors, who he says were "kinda upset when I passed the exam." It may go without saying that studying for the MW is an expensive proposition. "You can't live cheaply and taste a lot of great wine," says Reilly.

Then comes the exam. Candidates are judged on their tasting abilities in the mornings--yes, mornings--during the first three days. ("You spit," says Cree.) In the afternoons and on the fourth day come the theoretical essays--British-style, long-hand essays. (There's no multiple choice in the MW.) Candidates might be asked to expound on the place of hazard analysis in the international wine industry, or to analyze which sectors of the wine business will offer the most profitable return for the long-term investor, or to consider the best ways for a winemaker to manipulate alcohol levels after harvest to improve the end product. A recent exam asked would-be masters to "discuss the most significant developments of the last 100 years in the wine industry." Should you survive it, you're still not done. You have to get a dissertation topic approved by the existing masters and spend the next six months writing it.

The odds are, of course, that you'll fail the exam, especially if you're American. Back in 1953, 21 people took the exam, according to a history of the MW written by Jasper Morris, MW. Only six passed. Today the success rate has dropped to about 15%, and recently it has been even lower in the U.S. (The graders are reportedly often quite candid about their distaste for the way Americans write.) Some ten to 20 Americans try each year, and there was a bad string of four years when none were inducted. Until recently, there was only one American woman MW, Mary Ewing-Mulligan of New York, who first sat for the exam in 1989 and finally passed in 1993. "There were times when I was on the verge of giving up," Ewing-Mulligan confesses today. Thus, it was quite a cause for celebration last year when a 28-year-old American winederkind named Sheri Sauter, who only entered the program in 2001, earned her MW.

All of this, of course, raises a question: Why on earth do people, even those of the geeky oenophilic persuasion, subject themselves to this? It's not as though you need an MW to practice wine the way a lawyer needs a JD or a doctor needs an MD. (Robert Parker, whose ratings of wine are hugely influential, is not an MW.) When Sauter is giving a lecture or holding a tasting, she may not even mention that she has an MW. For one thing, her audience may not know what it is. And if they do, she doesn't want to add to the intimidation that often discourages people from drinking wine. All of this is why many MW candidates talk about the degree as an intellectual challenge rather than a mere scheme for professional advancement.

What MWs do stress is the need for objectivity in what is often regarded as a subjective business. Indeed, they view the poseur as not just a cocktail party annoyance, but as a real threat to the respectability of the industry. "Wine is so full of people who set themselves up as experts and don't know anything," says Reilly. An MW may not be able to tell you if you'll like a wine--"how can I know what's going on in your mouth?" asks Granik--but he or she will be able to expound on its qualities for hours. In other words, there are certain standards, and MWs are here to uphold them.

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