Dublin - The two men drink standing near the back of the long bar at Davy Byrnes, one of the many watering holes in this city that, in the words of writer Samuel Beckett, who once lived upstairs, have been known to house "broken glass and indiscretion." In the back, because that's well away from the "whippets" and "blow-ins" who tend to wander in, armed with neither intellect nor wit, if one distinguishes between the two, settle on the first available stool and ask for a "Boodweiser" from the barman.

Standing, because as the long, merry nights wear on, each of the men must be on his toes, or miss the opportunity to point out a deficiency in the other's grasp of 13th-century history, or drop a deftly delivered pun, or a magnificent lie.

"Some of the time I'm telling the truth. You have to figure out for yourself whether I'm having you on or not," says Roy McCutcheon, a native of Belfast who met Paul Winter here at the pub made famous by James Joyce - now a civilized "gastropub" with very little broken glass - one evening three years ago, and on a good many evenings since. "We're like-minded. We're very sharp, very quick, we've got a great repartee going on." "He's full of it most of the time," Winter says. "And he's a fascist." "I'm not a fascist. But you're a Trotskyite."

If there is a common denominator to these long, cantankerous evenings, it is Guinness, the beer so fundamental to Ireland that one has only to say, "Pour me a pint" to receive, in due course, a wide, ceremoniously poured glass of "the black stuff."

Bitter and muddy, thick with creamy foam, too meaty for the heat but a blessed lubricant for a foggy night and a tearful chorus of "Carrickfergus," Guinness is Ireland's best-selling beer.

Sixty-somethings like McCutcheon and Winter, weaned on its thick roasted barley essence as teenagers, wouldn't even consider drinking a wispy lager in its place.

But even Guinness, it seems, is not immune to the forces of open markets, suburban sprawl and Ireland's evolution from an impoverished backwater of emigrants to one of Europe's economic powerhouses, a country that now imports cheap labor from Eastern Europe.

Even as sales have boomed elsewhere, Guinness has seen its business decline in Ireland over most of the past seven years, a trend that eased only slightly last year with a growth rate of 3.5 percent.

The problem is, Irish traditions are something many Irish simply no longer have time for.

In Dublin, working and commuting now take up much of the time once spent stopping at the pub for a pint after work. And as the Celtic Tiger begins like everyone else to feel the effects of the global credit crunch, with declining home prices and rising unemployment, it doesn't help that a pint of Guinness costs $7.20.

"I've got a hundred-mile round-trip commute every day. So you're out of the house for 12, 14 hours a day, and by the time you do get home, all you're fit for is a couple of hours of TV, maybe dinner, and go to bed. It would never, ever cross my mind to go for a pint on the way home," said Cormac Billings, a 33-year-old investment banker who works in Dublin's city center but lives in the suburbs.

"Maybe six, seven times a year, you might meet up with your mates for a few pints, but it's always a hassle to organize," he said. "People are busy. They're married, they're having kids."

Ireland is still the second-biggest beer-drinking market in the world, after the Czech Republic. But beer consumption has declined by 15 percent since 2001. Rural pubs last year were closing at the rate of more than one a day, victims of high taxes, increasing supermarket sales and a nationwide smoking ban.

Add to that an explosion in demand for wine and high-end coffee here, and Guinness now sells more beer in Nigeria, where its extra-robust, 7.5 percent alcohol foreign extra stout, than it does on the Emerald Isle.

In May, the company announced a $1 billion modernization program that will close two of its most venerable breweries and eliminate more than half its brewery staff, while transferring most Guinness export production, including beer bound for the U.S., to a new large state-of-the-art brewery in the Dublin suburbs.

Production at Guinness's 249-year-old flagship brewery at St. James's Gate in central Dublin will be shrunk by a third, focusing almost exclusively on beer sold in Ireland and Britain - for those whose Guinness tastes are so refined they wouldn't accept beer brewed anywhere else. The facility, Ireland's biggest tourist attraction, also will get a major face-lift.

"We listened to our consumers, and we listened to ourselves. And something like St. James's Gate is really, really important to people," said Brian Duffy, chairman of the Irish branch of Diageo, the multinational beverage company that owns Guinness and also distributes Tanqueray gin, Smirnoff vodka and Cuervo tequila.

"Not just in terms of its connection with the beer and the connection with the family, but with Ireland. It is almost regarded as part of our heritage." Pub owners say they still sell more Guinness than anything else, but as Ireland has joined the European Union and become a new center for banking and manufacturing, they face a clientele with more choices and wider interests.

"Eastern European products you never heard of, all of a sudden they are on the supermarket shelves," said Tom Cleary, who owns Kennedy's Pub in Dublin. "And I suppose the affluence brings about a certain snobbishness. In terms of, 'We were on holiday and drank this, why can't we get this beer in Ireland?'

"I've had people come to the counter and ask me for a bottle of Czech beer. They think it's different, it's new. But with all this affluence, they don't appreciate what's in front of them."

Now, no one's saying that a Saturday night in Dublin isn't still an intimidating and unforgettable event, with the sound of raucous laughter, swooning promenades down the street and occasional curbside regurgitations followed, early Sunday morning, by the clatter of dozens of empty kegs being rolled down the sidewalks and onto waiting trucks.

Young Dubliners who made their first trip to the pub at their father's side as teenagers, receiving calm instruction in how to finish a pint of Guinness in seven neat swigs, still go when they can, but when has it ever been cool to drink your father's beer?

"Years ago, everybody drank Guinness," said David Donnelly, a 36-year-old Dubliner. "But young people don't drink Guinness. If I was going for a few drinks with me mates, we just drink Budweiser. Guinness is more of an old fellow's drink."

It is Guinness' fate to be so much better poured on draught at an Irish pub - where kegs are so often tapped, they get renewed daily - that a discriminating Irishman will drink it almost nowhere else. Sure, Guinness comes in a bottle or a can, its contents indistinguishable from the pub version to most beer-drinkers, but not to those who've sucked on the black stuff since adolescence.

And there's plenty of choice now, even at the tap.

Here at Davy Byrnes, so crucial a fixture in Dublin that Leopold Bloom ordered a gorgonzola sandwich and a glass of burgundy there in Ulysses , things have changed to the degree that one city pub review congratulates it for pouring "the finest pint of Budweiser in town!" Still, it's the Guinness that keeps barman Stephen Delany busy much of the night.

He's pouring to the exacting standards of McCutcheon and Winter, who want it to take as long as it's supposed to take, which is, officially, 119.5 seconds for the perfect pint. The first half is poured into a glass raked at 45 degrees, a process that produces a tumult of nitrogen and carbon dioxide that has to be left sitting on the bar to settle. Then, the second part of the pour, up to the brim.

"You must wait until the head rises over the top, and that's when you start. And if you drink it when it's first risen, the head will stay with you all the way to the bottom of the glass," McCutcheon says.

"If you go into a pub in another country, and they just pour the Guinness straightaway," Winter says.

"Refuse that," interjects McCutcheon. Guinness brewery workers, who are fighting layoffs, say they fear the move to a more automated new brewery will undermine the craftsmanship for which the beer has always been prized.

"It's going to have a huge impact on the heritage," said Sean Mackell, head of the brewery workers union. "We see Guinness as an iconic brand that should be produced by people who are committed to it. As opposed to a multinational company contracting things out and not having the same commitment to quality."

But Diageo officials point out that Guinness already is brewed in nearly 50 countries, its foreign extra stout prepared with top-secret feedstock transported from the mother ship in Dublin.

If anything, they and many pub owners say, Guinness' new focus on uniform brewing standards, rigid delivery and sales schedules and scrupulous tap-cleaning regimes at pubs across Ireland implemented in the past few years have made Guinness better than it used to be.

The campaign to make Guinness as good as it can be, along with a heavy marketing campaign, have helped turn around the slump in Irish sales last year. So what if a third of all Guinness is now sold in Africa?

"People keep saying Guinness is in demise. Well, it's not. We're a global business, we're sold in over 150 countries. I've seen all those places go up and down, but our general trend has been inextricably upwards, and I expect that to continue," Duffy said.

"As far as Ireland goes, we continue to be happy with the progress we're making. We obviously need to connect to new consumers as they come into the market, but we're not aiming for this to be the fad drink for every new consumer that decides to embrace alcohol."

Kim Murphy writes for the Los Angeles Times.