Anyone with a passing knowledge of Seattle’s grunge scene would have to admit that a while it did wonders for heroin chic, plaid shirts and torn jeans, humour was its first casualty. In any city that produced groups like Nirvana, Soundgarden, Alice in Chains and Mudhoney, with songs such as Smells Like Teen Spirit, Rusty Cage and Down in a Hole, jokes were bound to be thin on the ground.

So it comes as a considerable surprise to see Eddie Vedder, the lead singer with Pearl Jam, Seattle’s last surviving grunge band from the class of 1992, smiling. At the Astoria recently, during a show watched by, among others, a visibly excited Robert Plant, Vedder managed a beaming smile more than once. “I’ll know what to write about in the postcards home,” he joked, after a kilt-wearing Scot flashed him from the side of the stage. Earlier, after fluffing the intro to a new song, he had laughed: “We haven’t rehearsed this one as much as we have the others.”

For a group that stopped producing pop videos, shunned all endorsements, refused to release singles and once even declared a moratorium on interviews, Vedder’s pleasantry amounts to an appearance on Celebrity Love Island. “We were scared of being famous, scared of appearing as if we’d sold out,” he tells me a few days later. “Most people crave fame and find some comfort with it. Most of the Seattle bands I knew seemed to shun it altogether.”

The group’s eighth album, Pearl Jam — already redubbed “Avocado”, from the picture of the fruit on the sleeve — finds the band escaping the spectral gloom of their last two records. In fact, Pearl Jam, an album that combines the group’s classic Seventies influences with bristling guitars, has all the verve of a band making its debut recording. The album also finds Vedder’s songwriting overcoming the despair of recent years. After an initial four-song blizzard of riffs and Vedder’s angry howls, Pearl Jam settles down to become the band’s most muscular album in a decade. When, on the closing song, Inside Job, Vedder repeats “I will not lose my faith”, the effect is a bit like suddenly renewing an old friendship.

Like many of the group’s records since 1999, the album is informed by the politics of its makers. The first single to come from it, World Wide Suicide mentions President Bush, while Army Reserve eulogises the wives and children of the soldiers serving in the Gulf. But there is less hand-wringing than the band’s clarion call of 2001, Bushleaguer, a vitriolic attack on the Bush presidency that had the group vilified by the right-wing press back home.

“This is the world we live in,” says Vedder, who took his band on the Vote for Change tour of 2004, in support of John Kerry’s bid for the presidency. “We have to talk about it. I think America needs to start having a conversation with the wider world.”

Just as Pearl Jam features some of the most self-assured music of their career, the band members equally seem keen to engage with their audiences. It has to be assumed that the reasons for this are partly economic. While their debut album, Ten, sold more than 12 million copies in America alone and led to Vedder being lionised as the voice of a generation, the one before Pearl Jam, Riot Act (2002), sold “only” 500,000. “On that album, radio played our songs for only a minute,” says the guitarist Mike McCready. “And I have an ego to satisfy — I want to hear my band on the radio again.”

Later, bassist Jeff Ament talks of the anxiety he often feels on leaving home for the road again. “I watched everything that happened with Nirvana, those guys were always being pushed by their management, pushed to do more and more, and I never wanted my band to end up like that. So, while we continued to make music, we just had to go away for a while.”

For years it has been Vedder who has battled the most to control the group’s success. Little wonder that he struck up a friendship with Neil Young — Pearl Jam were the backing band on Young’s Mirror Ball album, in 1995. Vedder sees the Canadian as another songwriter who has, at times, deliberately sought to nullify his appeal. “If your band is this important to you, you have to try and stay sane,” he says.

In the past, Vedder, now 41, has sometimes appeared pensive during interviews but this time he is more at ease. Small and bushily bearded, he looks more like a globetrotting hobbit than a rock star. And, for a singer whose voice sounds unlike anything else in rock music today, he smokes cigarettes with alarming regularity.

He is also candid about the group’s early and meteoric fame. “I guess I got better at dealing with success,” he says, stubbing out yet another cigarette. “It was a difficult time for us in the glare of all the attention the Seattle scene was getting.”

He says the six weeks the group spent on the Vote for Change tour, which also included R.E.M. and Bruce Springsteen, gave the group a new lease on life.

For the first time in years, says Vedder, his songwriting began to look beyond the red, white and blue myopia of American politics. “I’d always assumed that many of our fans were Democrats,” he says, smiling. “It really surprised me when some of them told us they were Republicans. I now think there has to be a real dialogue between people of different political opinions. Otherwise, things will only get worse.” With that, he rises, reaches for his cigarettes, smiles once again and says goodbye.

Later, as I leave the hotel, I see him standing on the steps outside. He looks like a happy man, no longer the angst-ridden frontman plagued by the ghosts of grunge.

Pearl Jam is released by J Records