As an album starter, “Brennisteinn” makes a better introduction then, well, any introduction I can think of. The track doesn’t emerge from beneath the sound of wind over a mobile phone. Instead it truly bursts from its first few seconds. It’s a long pummelling from a trained pugilist, and a hosing-down on a freezing morning. It’s not what I was expecting …

I have struggled with this review. For some reason it’s taken me much longer to come to terms with this album than I expected. I think it has something to do with Iceland itself, the mesmerising, inextricable otherness of the place. With the release of Kviekur, Sigur Rós leap in a new direction. A grittier sound, shrouded in guitars, and driven by the percussion of collapsing glaciers – or maybe drums.

Released only a year after Valtari, Sigur Rós have doubled back on the evolution of their sound. Where Valtari was muted, controlled, and drawn out, Kviekur is short, loud, and dogged. Valtari was a logical progression but Kviekur is a better album. Perhaps they realised what many feared, that they had begun to settle into the ubiquitous noises of post-rock, and so they have actively tried to rebel against their own sound. They’ve channelled the influences behind ( ) and Agaetis Byrjun, but the sound is angrier now, and more energetic.

Kviekur is not only an outstanding whole, a beautiful, jarring, and disconcerting exercise in the otherworldly, it’s also a collection of songs you’ll beg to hear live. Each track drips with a liquid intensity. “Isjaki” and “Yfirborð” are obvious centrepieces for upcoming live shows, with their signature eeriness and crystalline beauty; and the title track, “Kveikur,” and “Bláþráður,” will wake up some over-comfortable audiences.

Post-rock is an acquired musical taste, and foreign language music hasn’t much traction in English-speaking markets, but Sigur Rós have been almost singularly successful. Listening to Sigur Rós is an extraordinary experience, feeling almost like an opportunity to partake in some sort of lost Norse ritual. There is a quality in Kviekur that I cannot articulate. It’s a feeling I recognise though: the experience of viewing a truly beautiful thing. I think this is when you’re actually supposed to use the word “awesome”.