The double R logo on the otherwise generic door doesn't tell you much unless, of course, you're already in the know.

Which is presumably the only way you'd find the Ranstead Room, the new cocktail lounge - a stylized speakeasy entered from Ranstead Street, the back alley that stutters across Center City, a half block north of Chestnut.

A single pink lightbulb colors the balcony above. You enter a dim antechamber that feels more like an air lock, and emerge into a dark, sedate room, votives flickering, nudes framed, the music determinedly pre-1964, though pop hits have been scrubbed, for the most part, from the playlist.

This is the classic cocktail world according to Sasha Petraske, the hot-hand mixologist brought in from New York to show the provinces a few moves - to spread the gospel of good ice and strong pours, proper comportment and deference to tradition, which means, he notes, that you must muddle only the sugar in an Old Fashioned, never the fruit.

He is 37 now, his first New York hit, Milk and Honey, 10 years in business after a shaky start: His fastidiously crafted drinks, fresh juices, stirred and fizzed, the ice cracked to appropriate dimension, weren't showing up at the tables exactly pronto. "The customer has to get used to [that pace]," he says. "They'd storm out."

He is operating betwixt and between - as a consultant hired by restaurateur Stephen Starr to establish the understated Ranstead, while just a kitchen space away, and entered from Chestnut at 20th, is Starr's lively, unapologetically loud El Rey, featuring Puebla-style Mexican street food.

He is operating, also, between two eras: It was Starr who 10 years ago brought a very different kind of retro cocktail lounge to Philadelphia - the Continental, in a tricked-out Old City diner, offering a long menu of big, boozy, girly-girl vodka - not gin - martinis.

This space off Ranstead, on the other hand, was until recently a rougher version of old school, a hard-core boozer's bar behind the old Midtown IV Diner.

Petraske's charge has been to train staff, oversee the level of the lumens, and designate the glassware: You'll be served your vermouth-friendly martini, or your $12 Boulevardier (bourbon, Campari and sweet vermouth) in a squat version of a wide-mouthed champagne glass, not the long-stemmed Sex and The City V-necked model.

The former's compactness, he said, keeps a drink chilled longer.

He is particular about the ice, as well, having small hotel pans of filtered water frozen daily in the basement, then chipped with wood chisels and rubber mallets into - among other sizes - blocks sized to fill a tumbler.

The density and production method of the ice causes it to melt at variable rates. Certain ice-machine makers boast that the maximized surface area of their cubes causes more rapid melting, resulting in savings for bar owners; up to 18 percent less alcohol required per drink.

His own target? The proper amount of ice to keep a drink cold without making it watery. That might mean, in a drink without juice or fruit, about 25 percent water.

A chunky piece of solid ice, he suggests, also allows you to nurse a drink without its becoming diluted.

As much as the mechanics of cocktail-making, though, Petraske has a mood in mind: "The ambience is a place for people old enough to know how to drink; strong drinks in a [grown-up] environment . . . no dancing on the table or screaming and shouting."

Anyone is welcome to come in, he says. But they're not always welcome back: "Postgraduate drinking," he calls it, distinguished by "offhand excellence," where status brands aren't named on the menu and the bartenders aren't performance artists.

He noticed something close to that, he said, on a visit to Franklin Mortgage, the subterranean bar at 18th and Sansom (also plotted out by a New York consultant). He was less effusive about other classic spots in the city.

That feeling, it's fair to say, is mutual. "Condescending," is how one longtime Queen Village mixologist described Ranstead after his first visit.

For the bar staff at the surviving lounge at Midtown III, a few blocks away at 18th and Ranstead, the revamped room behind El Rey was causing nary a ripple.

The regulars spent their time one night last week speculating on the salary Vanna White was making to turn the letters on Wheel of Fortune, playing on one of the flat-screen TVs above the bar.

They teased each other. Told stories about wayward ducks rescued at the Oregon Diner. Advised newcomers that, no, there were no drink specials - just drinks.

They were, in a word, socializing. And though there was no screaming this particular evening, there was a fair amount of banter that you could say rose now and then to a level - in a tipsy sort of way - that could be described as shouting.