WHAT’S THE difference between Guinness Stout and Coors Light?

Judging from the sound of the blather coming out of St. James’s Gate in Dublin these days, not much.

You can’t read the morning newspaper through a glass of the creamy stout – yet. But the way the folks at Guinness talk, you’d think their famously black-as-ink Irish ale is the fermented equivalent of clear-as-water American lager.

In the world of bland, mass-produced beer, Guinness Stout is an iconoclast. It uses no adjuncts like rice, corn or sugar in its brews. You can actually taste the hops. And, of course, its dark barley malt gives it a distinctive, full-bodied, roasted, bitter flavor.

Instead of being splashed into a frosted mug, it is poured slowly into a pint glass and consumed at a so-called “cellar” temperature of 45 to 50 degrees, to better savor its complex flavors.

In a world where Budweiser is God, it’s an astonishing quirk of heresy that beer drinkers drain more than 10 million glasses of the stout every day.

Selling even more, though, is a struggle. In Ireland, where sales are down, young drinkers are mimicking Americans, reaching more often for lighter, refreshing lagers they can chug straight out of a bottle.

Kind of tough to persuade the MTV generation to stand in line and wait for the bartender to pour them the perfect pint. Dark, heavy, warm, bitter – Guinness is a beer for old codgers, the sort of grizzled vets who have time to contemplate a few pages of “Ulysses.”

What to do?

You can’t turn stout into pilsner, but that didn’t stop the marketing division at Guinness from trying.

First, they started to blather that Guinness is actually “light” beer. The draft version is just 4.3 percent alcohol – lower, even, than Bud. (Bottled Guinness Extra Stout is 5.5 percent, but it’s not a big seller here. Other countries, like Belgium, get a different bottled Foreign Extra Stout with up to 7.5 percent alcohol.)

Then came the calories. Check out Guinness’ Web site, and you learn that its stout has fewer calories than skim milk.

Skim milk? We’re talking beer, here, not the kiddies’ school lunch.

The latest tack is serving temperature.

Now, for the last 200 years, Guinness Stout – like almost all ales – was served somewhere around 40 to 50 degrees Fahrenheit (4.5 to 10 degrees Celsius). In his “Beer Companion,” author Michael Jackson writes, “Guinness best expresses its complexity of flavors when served at a natural cellar temperature, but survives a gentle cooling.”

Compare that to the new Guinness Draft in bottles, which advises, “For maximum enjoyment, we recommend chilling…in the fridge for at least three hours before serving.” Not only that, it’s “specifically designed to be drunk straight from the neck.”

A nitrogen-loaded “widget” that rattles around in the bottle is supposed to give you the “draft experience.”

What the…?

I got Guinness head brewer Fergal Murray on the line and demanded some answers.

“You don’t have to drink Guinness warm – that’s a myth, a fallacy,” said Murray. “I recommend drinking the draft version at 3.5 degrees [38 degrees Fahrenheit], so it’s cold and refreshing.”

But what about the glorious, toastlike flavors of its malt, the fruity bitterness of hops – won’t those be lost when the taste buds are ice cubes?

“It’s true, there will be some diluting sensation in the flavor,” Murray acknowledged. “But that’s balanced out by the refreshing context. You want to drink it fast, not sip it like you would a warm beer.”

Out of a bottle? What about the cascading bubbles and the creamy foam of the perfect pint?

“There’s no real heresy in moving from the pint to the bottle,” he said.

Hell, why not chug it from a bong while yer at it? Maybe you can hire the Coors twins for your next commercial.

“We’re not turning toward lager beer,” Murray said. “We stand up to our belief that we’re still making great beer.”

Maybe. But it sounds to me like they’re messing with tradition – and that’s a huge selling point for this 250-year-old brewery. Yeah, Guinness could sell tons more beer if it were clear and golden and fizzy and tasteless.

But then, it wouldn’t be Guinness Stout.

Joe Sixpack, by Staff Writer Don Russell, was written this week with a bottle of Yards Love Stout.

-30-