"Dean Ween picks his favourite Ween disc, gives the back story on La Cucaracha'"

If there was one moment more surreal than all the rest during the creation of La Cucaracha, it was when Ween met the harpist. The pride of New Hope, Pennsylvania, was holed up in a beyond-squalid farmhouse on the night in question, in the kind of head space that the band's fans would describe as "brown".

Ween was being put through the grinder by its long-time producer, Andrew Weiss, a man that guitarist Mickey Melchiondo (aka Dean Ween) can't gush enough about. Weiss was determined to get a definitive version of La Cucaracha's 11-minute opus "Woman and Man", and he didn't care how many takes were required to get things perfect. If that wasn't contributing to the mental well-being of Ween, there was the added problem of the farmhouse, which was doubling as a studio. Imagine a filthier version of the digs from Tobe Hooper's The Texas Chainsaw Massacre reimagined by the art director of Hostel, and you've got a good starting point. It was into this less-than-five-star scenario that harpist Gloria Galante walked. Evidently, she was so proud of her contribution to La Cucaracha's marshmallow-soft "Lullaby" that sending it in by computer wasn't going to cut it.

"The woman who plays the harp on that song wanted to hand-deliver it," Melchiondo says, on the line from home. "She came on one of the 10 nights that Andrew made us do 'Woman and Man'–I think we recorded 500 minutes of that song because he wanted it in one shot. So she shows up, and everything is really uncomfortable because we've been at it forever. She's this grown woman who played in the Sun Ra Arkestra stepping into this filthy farmhouse that's covered in cigarette butts and empty beer bottles, with gear and shit everywhere. She's standing there looking around, and then all she could say was, 'Ummm, here.' "

Whether Galante was more familiar with Ween than, say, jazz-sax legend David Sanborn–who guests on La Cucaracha's smoother-than-Bailey's soft-rock closer "Your Party"–is debatable. But there's no question that she helped make "Lullaby" into one of the most beautifully demented offerings in the band's catalogue. As everyone who has ever sung along to "Mister, Would You Please Help My Pony?" or "The Blarney Stone" knows, that's saying something. You want twisted? Sounding like a nursery tune for Holiday Inn barflies, "Lullaby" delivers, right from the moment that singer Aaron Freeman (aka Gene Ween) starts crooning "Floating like a ghost man/Floating like a baby" over soft-glow piano.

That's just the start of Ween's now-patented genre-hopping craziness. For those nights when no amount of uncut crank is enough, Ween hunkers down in the garage with the grunge-splattered "My Own Bare Hands", which features such tender sentiments as "She's going to be my cock professor/Studying my dick". "Learnin' to Love" is old-time country aimed at inbred alcoholics, "The Fruit Man" takes dub-drenched reggae to spliffed-out new lows, and "Woman and Man" fuses sun-splashed calypso and '70s-style guitar heroics with ass-shaking results. It all adds up to the mightiest, most Boognishalicious Ween album since 1994's landmark Chocolate and Cheese.

"We had three CDs of material, but I didn't really have any idea what the CD was going to sound like until Andrew put like 20 of the songs on a disc," Melchiondo says. That was the first time I heard it as a record, and I got really excited about it. I was like 'Oh yeah, this is going to be really, really fucking good.'"

The guitarist will argue he's not the best person to decide where La Cucaracha ranks among Ween's nine studio albums.

"My relationship with Ween records is totally different than anyone else's, other than Andrew's and Aaron's," he reveals. "None of us listen to Ween records, ever, after they're done being mastered. The only time I put one on is if we're trying to work something out for the stage and I have to listen for arrangements or parts. I will say that the only record that I ever felt really confident about was The Mollusk. That's my favourite record we've ever done. I couldn't wait for that one to come out."

Having started out as a duo playing clubs the size of suburban rec rooms–anyone remember the old Cruel Elephant?–Ween's two main men today find themselves headlining 2,000-seat-plus theatres with a full band. Still, when Melchiondo looks at where the band is today from a business perspective, you can't help but feel that things are even more fucked-up than La Cucaracha. And, yes, that's saying something.

"If Ween was to stop right now, I have a nest egg that would enable me to survive for about 10 months," he says. "We definitely are privileged to do what we love, but there's never been any one moment in Ween where we've ever got any kind of major payday. Going out and touring is fun, but it's taxing to the point where it fucks your head up. That's why so many musicians end up addicted to drugs. It's the only way to get through it."

Ween plays the Queen Elizabeth Theatre on Wednesday (November 14).