Every new organ concerto promises deliverance from Francis Poulenc - the French composer who gave organists the one of the few showcases that regularly turns up on mainstream symphonic programs, and maybe too often. Perversely, the new Christopher Rouse Organ Concerto, being premiered by the Philadelphia Orchestra on Thursday, begins by quoting from Poulenc's Concerto for Organ, Timpani and Strings.

Might soloist Paul Jacobs be thinking, "Oh no! Not again."? Actually,  he and the orchestra's music director, Yannick Nézet-Séguin, lit up at the discovery: It's a familiar window onto something new. With Rouse's taste for ultra-fortissmos, the quotation is likely to be an inaudible inside joke. And considering how much the 67-year-old Pulitzer Prize-winning composer has expanded the sound envelope of symphonic music, you wonder what took him so long to write for an instrument with the earthshaking possibilities of the organ. In fact, his concerto begins at triple forte. And with Kimmel's Fred J. Cooper Memorial Organ, the composer knows he'll get to it.

"Sometimes you have to write five or six fs just to make a point,"  Rouse said in a phone interview from Baltimore, where he teaches composition at the Peabody Conservatory. "But with organ, there's a loud trumpet stop. It can really blast."

"It has plenty of octane,"  Jacobs said of the Verizon Hall instrument. "But the piece is never harsh. There are moments of enormous tension, but it does have a playful quality."

Playful? From the composer who has written pieces dedicated to Led Zeppelin's deceased drummer, John Bonham? Certainly, the playfulness has an underlying edge. "Yes, you could say that,"  Jacobs said with the kind of tactful understatement you might expect from the head of the Juilliard School organ department.

Or from Rouse  -- who has long been a low-key presence cutting a stark contrast to his music, which is best described in the composer's own words -- "expressive urgency." But you never know what form that will take. Terrifying contrasts in loudness and orchestral color is one possibility, reflecting his younger allegiances to rock groups such as Led Zeppelin. But his breakthrough Symphony No. 1 was a quiet adagio that seemed to be waiting for something horrifying to happen. Here is a performance of the symphony by the Baltimore Symphony Orchestra:

Some of his most penetrating works have been memorials to deceased loved ones and colleagues, such as composers Leonard Bernstein and Stephen Albert. His Symphonies Nos. 3 and 4, recently recorded by the New York Philharmonic as part of his three-year artist-in-residence stint with the orchestra, show a wildly mercurial temperament rather than a discernible progression from one piece to the next. Here is a performance of the Rouse Symphony No. 3:

How the Organ Concerto fits into his output can initially be defined by what it's not. There's no programmatic subtext. Much of the piece has the trumpet/organ pairing that has been popularized by the Canadian Brass. Sometimes, the piece seems downright conciliatory. "I had a terrible time writing the program notes," Rouse acknowledged. "It's just a piece of music. There was nothing that inspired me other than just writing the organ concerto."

Always interested in extremes, Rouse had to abandon some ultrafast passages he wrote for the soloist upon discovering "the organ doesn't speak as quickly as a piano."

Not being a card-carrying organ composer, though, can translate into outsider ideas that do work. Jacobs talks about the middle movement's intimacy, not a quality often achieved by such a grand instrument. The organ also took the composer onto roads less traveled, such as the counterpoint of the final movement that's so much a part of the organ's tradition -- but not Rouse's. What about his heavy-metal heritage? Rouse says that didn't come into play here. But what rock fan of a certain age could forget Virgil Fox's 1970s "Heavy Organ" concerts at rock venues? You never know what's  in a composer's subconscious, says Jacobs.

Then again, few composers can claim complete ownership of their organ compositions, if only because those who play them can have such an impact on the cosmetic aspects of the music. Rouse's score has loudness markings but leaves decisions on what "stops" are used to Jacobs, who is in some ways a co-orchestrator, taking cues from what the composer is after but bringing it into being in his own way. In fact, Jacobs spent from 5 to 11 p.m. Friday at the console of the Verizon Hall organ, working out the details in anticipation of the first rehearsal.

"We have many mechanical considerations in our music-making, but these should never be evident. All of the piston-pulling and gadgets on the console shouldn't affect the freedom of the phrase, and the freedom of the music," Jacobs says. "It's sleight-of-hand, in a way." And for that, he needs to use the onstage console rather than the loftier console in the Conductor's Circle, where 16-foot reeds are just a few feet from his ears.

The game plan will no doubt change when the concerto is performed by its other co-commissioners, the National Symphony Orchestra and the Los Angeles Philharmonic, if only because of each organ's specific qualities. The good news is that Rouse is recognized on a level that allows such multi-orchestra commissions to give his new works extra legs. Even Pulitzer Prize winners such as himself don't often have the luxury of the three-year residency he had with the New York Philharmonic, which included a performance of his massive Requiem. "I'm not holding my breath to hear it again in my lifetime," he said.

With 11 concertos and four symphonies behind him, though, you have to wonder what new compositional incongruities are left to him. Opera? Not likely, he says. "Opera companies want to know they're dealing with a composer who has a track record in opera," he says. "And I'm not one of these people who feels my life would be wasted if I didn't write an opera."

Which may just mean that opera is what is coming next.

The 10th Anniversary Fred J. Cooper Memorial Organ Celebration. Yannick Nézet-Séguin conducts. Paul Jacobs, organ. Selections include the Organ Concerto by Christopher Rouse. 8 p.m. Thursday, Verizon Hall, 300 S. Broad St. Tickets: $36-$143. Information: 215-893-1999, www.philorch.org.