(WSJ) -  ONE OF THE MOST satisfying achievements of any oenophile is an ability to recognize a wine whose identity is concealed. Equal parts talent, training and luck, blind tasting is the elusive grail of the professional wine world. I've had some great blind-tasting successes—and many failures—but my favorite experience took place 15 years ago at the now-closed Montrachet, in New York.

The restaurant's then-wine director, Daniel Johnnes (now wine director of Dinex, the Daniel Boulud restaurant group) conducted a game called What's My Wine? The challenge was quite simple: Mr. Johnnes poured willing diners a glass and asked them to correctly identify the grape, appellation, region, vintage and producer. For each correct answer, Mr. Johnnes deducted 20% from the price of the bottle. Anyone who answered all five correctly got it free.

I answered four out of five questions correctly: Chenin Blanc, Savennières, the Loire Valley and 1995. I didn't name the producer, Nicolas Joly. I can't remember why. Perhaps it was too obvious. "Only about 2% of all the people who played the game got as far as you did," said Mr. Johnnes reassuringly when I recalled the competition during a recent phone call.

But when I recounted my almost-total triumph to a wine-savvy friend, he scoffed that people almost always guess wrong at blind tastings. "They only remember the one time they got it right," he said.

The practice purportedly evolved from a professional need to identify fraudulent wine (bottles didn't come with labels long ago). Today this type of tasting is considered the best way to assay the true quality of a wine. When a drink's identity is unknown, a taster can (theoretically) reach an objective conclusion as to its worth. Then there is the other type of blind tasting—practiced by professionals and amateurs alike—which is more of a parlor game meant to challenge and/or humiliate wine-drinking friends. Both kinds generally involve shrouding the bottles with brown papers bags, but anything all-concealing will do. I've even seen aluminum foil employed.

The reviewers at Wine Spectator certainly go through the exercise for the first reason, as executive editor Thomas Matthews noted in an email. It is important to avoid "the inevitable bias adduced by knowledge of price and producer," he said in an email. The magazine's critics review all new-release wines in independent blind tastings, he added.

Daniel Posner, owner of Grapes the Wine Company in White Plains, N.Y., blind tastes with his staff for fun. It can be "very humbling," he said. He also does so to assess the quality of wines wholesale sales reps present, as his shop is small and he must be selective about what ends up on the shelves.