For many people, Dave Grohl will always be the drummer from Nirvana first and foremost, the frontman of Foo Fighters second. But the first Foo Fighters album turns 20 tomorrow, which means at this point there has to be many others who first became aware of Grohl because they heard “Everlong” on the radio or in the mall or anywhere, or they saw any video in the long lineage of Foo singles on Fuse or whatever. They know him not as the unstoppable drummer providing the engine for Kurt Cobain’s music, but as his own man, up at the front of the stage in front of massive festival crowds, headlining arenas, growing into the Alt Nation era’s leading champion of good old-fashioned rock ‘n’ roll ideas. As the band itself turns 20 too, does that make them officially classic rock? Since this debut, and particularly in the ’00s onwards, Grohl has certainly grown in that direction: continuing to churn out dependably professional and catchy radio-rock that either never strays too far from a ’90s alt-rock template, or starts to incorporate more Tom Petty influence than, say, Hüsker Dü.

By the time you get to last year’s Sonic Highways, just when the debut’s birthday was around the corner, the two-decade journey seemed complete. The Foo Fighters of 2014 sounded similar to how they always had, but it had reached a point where it was difficult to discern that any sound on that record came from a culture that was once considered underground or alternative to any extent. I mean, its name could’ve been taken anywhere from the ’70s, and it was inspired by the classic music history of various American cities. This was the Dave Grohl some people grew up with: charming, effective Big Rock singer, the torchbearer for rock in multiple forms, whether the stuff of his youth or the stuff he was at the center of in the ’90s, the stuff initially positioned as burning down that past. To a young listener with access to everything in the ’00s and ’10s, Nirvana and Led Zeppelin were increasingly becoming a part of the same family anyway.

All of that is to say: Foo Fighters turning 20 is a stranger-than-usual anniversary to experience, whether you’re looking at where the album falls in Grohl’s career or in the arc of the ’90s or in the grand scheme of popular rock music in the last two decades. It’s easy to forget, knowing the affable Dave Grohl of today, knowing Foo Fighters’ reliable formulas, that this was something of a gamble for Grohl. These were primarily songs he’d written during Nirvana’s existence, and it’s hard to wrap your head around how difficult it must’ve been to put this stuff out into the world when you were in a band with a lionized songwriter, an icon whose tragic death would be one of the definitive moments of the ’90s. He tried to maintain anonymity as long as possible, hence the moniker Foo Fighters when in reality this was all him, with the band itself yet to form. He casually distributed cassettes, set up limited pressings, and yet knew he had to face the looming and inevitable comparisons to Nirvana and Cobain, questions about why and how he could continue making music at all in the vein of Nirvana.

Anything about Foo Fighters being this quiet and small-scale is part of what makes the self-titled such a fascinating origin. Everything since has, in some form or another, been the pinnacle of slick, professional rock music. Foo Fighters, by comparison, is raw and loose. Grohl famously recorded the entire thing himself (except for the Afghan Whigs’ Greg Dulli’s guitar work on “X-Static”) in one week in October 1994 — a purge or escape route after the loss of his friend earlier that year. And while the project might’ve started personal and private, the music within didn’t bear any of the kind of introspection or meditation that you might expect from the circumstance. Most of Foo Fighters charges along in ways more genuine and effortless than latter day tracks by the band. You can feel the urgency of Grohl needing to do something, anything, to move forward.

Foo Fighters is an anomaly in the band’s catalog. While you can hear the beginnings of the band’s personality here, all of that clicked in on its successor, The Colour And The Shape, which really established the template for what Grohl’s new project would become. While there are gems throughout the band’s catalog, it’s tempting to wonder what Foo Fighters would’ve looked like if they’d continued on more along the lines of the debut than what followed. It isn’t hard to hear a version of the band developing out of this that stayed a little scuzzier, a little more intimate. Grohl wasn’t confident as a singer yet. While there is plenty of scraggly yelling here, it’s before he became over-reliant on bellowing the big choruses, before all the pile-driving arena-rock stuff. Ultimately, Grohl was too much of a certain kind of pop songwriter to keep making records like this. Foo Fighters are immediate in a shaggy and scrappy way; the rest of the band’s work is immediate because it’s pop craftsmanship, the tools happening to be big distorted guitars and pounding drums and Grohl letting you know a chorus is cathartic more so than just letting it be. But that’s OK, that’s worked well for them more often than not. They deliver a specific product, a mainlining of energy that they know how to deliver exceedingly well.

There’s something special and more rewarding about Foo Fighters for the fact that it’s more or less a one-off before all that. Maybe it’s because Grohl had been crafting these songs in the background, not knowing what sort of life they’d eventually take on. Maybe it was because the moment this captured in Grohl’s life, so soon after Cobain’s death. Whatever it was, the catharsis and impact of these songs is simpler yet more earnest. “Alone + Easy Target,” “Good Grief,” and “I’ll Stick Around” are all still some of the best Foo Fighters songs, rockers that might not fold outward as precisely as something like “Everlong” or “Best Of You,” but possess this undeniable pulse, this desperate energy. Speaking as someone who likes most of Foo Fighters’ work, there’s still an inescapable feeling that there is something subconsciously calculated about latter-day standouts like “The Pretender” or 2011’s Wasting Light. The particulars of how they sound might alter ever-so-slightly, but there’s an equation Foo Fighters have in their blood now for how a Foo Fighters song is supposed to work. You could never picture this band putting out songs in the tone of “Good Grief” or “Alone + Easy Target” again, or especially songs like from the blearier, spaced-out end of Foo Fighters, like “Exhausted,” “X-Static,” and “Oh, George.” At one point, Grohl was apparently considering the idea of Foo Fighters’ current iteration re-recording the self-titled for its 20th birthday. Chances are it wouldn’t have been that good or revelatory, but it’s still curious to think of the well-oiled machine they are now revisiting, for a full album, the music Grohl made when he had no idea what came next.

Any of this is relative to the rest of their career, though. Foo Fighters was still a major rock album, spawning its own clutch of singles and reaching Platinum. This is an album people knew, it’s an album people heard. And if The Colour And The Shape cemented what Foo Fighters would be, this album still started that progression. Oddly enough for a debut of what would be one of the last big rock bands, Foo Fighters is a transitional record — not just in Grohl’s life, but for the ’90s. By 1995, that initial grunge era was folding up, but Grohl, improbably, became a golden chid in the late-’90s radio-alt-rock world, an era that is otherwise mostly the kind of thing we should forget. And, improbably again, with Foo Fighters still filling arenas in 2015, that means the aging rock journeyman Grohl we now know has his roots in that same transitional moment in 1995. If Foo Fighters have a record people would call a classic, it’s The Colour And The Shape; that’s their most iconic contribution to the ’90s. But there’s something to be said for Foo Fighters being its own kind of ’90s classic, Grohl’s personal effort to carve out his own identity that also contributed to a demarcation in hindsight. The Colour And The Shape might be their best album, the most quintessentially Foo Fighters album, but Foo Fighters might remain the most enduring entry in their catalog: the beginning that no one expected, that only hinted at what would follow, but is more surprising and gratifying than almost anything else they’ve made in the two decades since.