In the late 1980s, a young group of musicians in Palm Desert, California cut their teeth playing “generator parties.” Small crowds would gather in the desert with gasoline generators and copious amounts of beer and cannabis. And into these sparse, potsmoke filled wastelands, stonerrock pioneers Kyuss would play directly to the crowds, free of the politics of club owners and venue promoters.

Welcome to Sky Valley was recorded a long way from those desert fetes. It was released on a major label, for crying out loud. But three free-flowing, organic spirit of those early performances is imprinted directly into this album’s DNA.

Kyuss is one of those bands that I knew by reputation before I ever heard a note of their music. Even beyond their indelible influence on bands like Elder and Sleep, members of Kyuss went on to form alt rock favorites Queens of the Stone Age. And admittedly, it took quite a few listens for this album to click for me. But once it did, it was locked in.

The thing that flipped the switch for me was their desert party origins. These songs make much more sense being played by a band powered by a generator, their set time dictated only by the supply of beer and gasoline than they do through headphones off of a laptop (or maybe also blasting from a motorcycle roaring down the highway, but I’ve not experienced that myself, so that’s a conjecture). The songs are long and organic, the structures seemingly built in real-time by the band playing off of one another rather than carefully deliberated in the studio. The lyrics are similarly freeform, instrumental jams punctuated by ad-libbed vocalizations.

And admittedly, this is the kind of album that a major label would have only released in the early-to-mid 90s as everyone was trying to beat each other in the race to find the next Nirvana. The ten songs are organized into three movements, each combined as a single track on the original CD. There’s no obvious single here, let alone identifiable choruses. Vocalist John Garcia is a bit rough around the edges (early 90s, remember, so there’s plenty of clenched-teeth delivery), but he’s largely absent through much of the songs.

Instead, the album gets its strength from the interplay between the musicians. Brant Bjork’s drums are urgent and demanding. Bassist Scott Reeder jumps around the fretboard with a gymnastic virtuosity. But as democratic as these jams are, the mastermind here seems to be guitarist Josh Homme, who proves himself to be a riff master in the tradition of Black Sabbath’s Tony Iommi and Melvins’ King Buzzo. This is especially obvious in tracks like “Demon Cleaner” and the plodding, muscular “Asteroid.” But even beyond his drop-tuned, highway-ready heavy metal riffs, he also experimented liberally with effects pedals, making for some of the most interesting guitar work in 90s hard rock. This mastery of atmosphere is especially obvious in the seven-minute, Eastern-tinged, acoustic-led “Space Cadet,” where his electric guitar is used to mimic a sitar. However, it even shows up when the band is running at full tilt, such as the solo section of explosive opener “Gardenia.”

And as much time as the band spends shifts between speeding urgently through 100mph riffs or patiently blossoming through more atmospheric jams, they’re undoubtedly at their best when those elements converge. This is most obviously seen on the closer “Whitewater,” which punctuates punishing halftime riffs with subdued instrumental sections that blossom with an electricity not too unlike that of Miles Davis’ electric period.

Admittedly, this isn’t an easy album to get into cold. There are some dated elements (most obviously, the vocals), and some moments aren’t as effective after being divorced from the desert generator parties (in what other context would the expanding distance between chord hits in “Supa Scoopa and the Mighty Scoop” make sense?). But when you take these songs on their own terms, this record blossoms into a masterpiece that is as rewarding as it is influential.