One drink can reveal your secrets.

Not that you won't spill them yourself after five or six. But a single cocktail order tells a lot about a person. It could be quite flattering if, say, you habitually order martinis and call the details: Boodles, dry, with a twist. On the other hand, waving down a bartender and requesting a Long Island iced tea says something quite different about your maturity.

Cocktails exist within a caste system. The upper crust consists of classics such as martinis, Manhattans, old-fashioneds and negronis. These are stodgy concoctions from an era when cool, mannered gentlemen welcomed a stiff drink well made.

Long Island iced teas and or Sex on the Beach marks you as a novice to the cocktail world. "With young people, the first [priority] is a lot of alcohol," explains Karel Zucharda of Bar and Books.

The younger crowd is also driving the trend toward sweeter drinks that obscure the alcohol, making them easy to knock back. "[They] don't like complicated drinks," says Hapu's Martin Streško of younger patrons. "The Manhattan, the old-fashioned, they're all about balance."

Many discriminating drinkers disparage popular blends like rum and Coke and screwdrivers as "mixed drinks," a lower status blend. To earn the sobriquet "cocktail," the glass must contain at least three ingredients working in harmony, each part noticeable on the palate, brought to life by a skilled hand.

Bartenders will tell you that anybody can shake, stir or mix a decent cocktail. What's harder is picking up on, and memorizing, local trends and regional favorites.

"You have to learn 200 cocktails," says Petr Chmelík of Alcohol Bar. Still, the majority of orders center around a core of 40 mixed drinks and cocktails, with mojitos and cosmopolitans generally topping the list. Recipes are readily available and techniques easily learned, and good brands and fresh mixers almost guarantee results worth sipping.

So what brings people in the door? "It's about personality and atmosphere," says David Bursa, a bartender at Tretter's. "It's not about the cocktail, it's about the place."

He and many other barhands contend that the same drink will taste different from one place to the next, or even from one day to the next, depending on the ephemeral workings of mood and ambience. A DJ beatmatching Kylie Minogue tunes can ruin a perfectly prepared negroni; the sudden appearance of flabby, topless stag partyers turns that chilled martini into something regrettable.

"That's true," opines Stefan, a Parisian expat sampling cocktails at Hapu. "Mood has a lot to do with it." After two quick slurps from a tall glass, he adds, "My mood is getting better."

Ambience notwithstanding, it's a long-held belief among bartenders that they can glance at people approaching the rail and, as Chmelík says, "know what they'll order before they order."

This myth is based on a few simple assumptions and, perhaps, suggestive selling techniques. If some guy wanders in dirty and tired, wearing blue coveralls, he's clearly unlikely to scrutinize the selection of gin before asking for a gimlet. By the same token, women tend to order lighter, sweet mixed drinks, men opt for more potent cocktails and twentysomethings generally head for the names most recognizable to their generation.

When a young woman approaches the bar, staffers work the self-fulfilling prophecy. "I always suggest something the first time," Zucharda explains. "Women like sweeter, so first I ask about a sweeter cocktail." For men, he might wave at the row of single malts or mention the classic martini. It's the nightclub version of "Want fries with that?"

"There's no magic," Streško agrees. "It's just a way to sell things."

Which is a good bartender's job. By knowing the products, chatting with customers and asking about their preferences, they set a mood in which cocktails work. As Bursa says, "We don't sell a drink, we sell atmosphere."

For proof, you can walk into Chateau, glance at the gin and the container of slowly wilting limes and ask for a gimlet. "I don't know what that is," the bartender will say.