One might wonder why Edward Gardner has taken so long to get to Salome, but it soon becomes clear that the self-confessed Strauss fan (‘There are pieces by Strauss that I would go to my grave with,’ he says) has an ambivalent relationship to the composer’s operatic breakthrough of 1905. ‘When I went to hear it a lot in the theatre, at Covent Garden and elsewhere,’ he explains, ‘I felt like curling away from it in a foetal position. The experience was so unnerving: a stage full of characters you couldn’t identify with, you can’t love.’

It’s also clear, however, that he could hardly have wished for more propitious circumstances to tackle the work: with extensive rehearsals and semi-staged performances in Bergen before the Edinburgh International Festival performance with the Bergen PO recorded and now released by Chandos. ‘There was the freshness of working with an orchestra who had no concept of the piece. I’m not even sure they’d ever done the Dance of the Seven Veils. So we really got stuck in!’

Strauss’s score accommodates some 100 minutes of music into around 350 dense pages, each teeming with detail, so I begin with a question about the work’s structure and the remarkable – and still viscerally shocking – final scene, described by Michael Kennedy as a ‘perverted Liebestod’. Does everything in a way work back from that? ‘It’s funny,’ Gardner responds, ‘how Salome feels as though it’s in three parts as you conduct it. And I remember, after a week or so of rehearsals, getting to the contrabassoon solo [five bars after fig 151] and the whole scene with Herod and thinking, “Great, I’m halfway through.” But you’re not!’ He laughs. ‘You’re barely a third of the way through. But it’s interesting what Kennedy said, because you need to find …’ – he pauses, to find the mot juste. ‘You need to energise that final section, because it does feel in some ways like the most inflated coda in musical history, this demented Liebestod.’

For me, I note, this is also when Strauss takes us right into Salome’s mind. ‘You’re in her head – I think that’s right,’ Gardner responds. ‘In elements of the first two thirds of the piece she’s a Lulu-like cipher; we’re putting things onto her. But we’re with her after that dance, we understand her, we’re there. It feels like there’s a psychological spotlight on her that the piece avoids until then.’ This, I suggest, is one of the many fundamental and telling ways in which Salome differs from Elektra, despite the fact that the works – both snappy one-acters named after their female protagonists – are often lumped together. ‘Exactly. And with Elektra, certainly after Clytemnestra’s scene, you know where you’re going; it feels like a journey that’s consequent in a way that Salome doesn’t.’

We jump back to the opera’s opening, and the slithering clarinet line that Theodor Adorno heard as the sound of the curtain going up. ‘I think of it like that too,’ Gardner agrees. ‘And that’s the polar opposite of Elektra, where it’s like “BAAAAH!” and then it’s that gorgeous, almost Ravel-like late-Romantic world.’ And what of Salome’s entrance, sidling almost unnoticed into the drama? ‘Again, it’s the opposite to Elektra. And, of course, with the waltz, this being Strauss … Let me get the page up.’ He flicks forwards on his iPad. ‘It’s a beautiful, swinging, breezy waltz.’

I mention an oft-heard description of Salome as a tone poem for the stage: a score where barely an idea or image passes by in the libretto – cut down by Strauss himself from Hedwig Lachmann’s German translation of Wilde’s French play – without the orchestra adding its own description or comment. Does that make it especially challenging? ‘For me, that’s all Strauss,’ Gardner responds. ‘As a conductor he was brilliant at keeping the line through music and you have to have that in your head – it’s a constant challenge. On every page there’s something miraculous.’

There must also be challenges involved, I suggest, in the score’s best-known – and most oft-excerpted – passage: the Dance of the Seven Veils, composed by Strauss separately after the rest of the work. Does Gardner, I wonder, see this as a separate, stand-alone set piece? ‘No, I really don’t,’ comes the definitive reply. ‘Of course, you’re right that it’s a kind of discrete piece in its own right, but the build of it and the conversation that it’s come out of in the opera – it’s so clear. And it really shows Salome taking control of the opera, of everything.’

The idea of Salome taking control brings us back to the final scene, surely one of the most intense 15 minutes in all opera. How, I ask, does a conductor go about pacing that? ‘I had the huge benefit of doing it with Salome sung by Malin Byström, who has done the role so much,’ Gardner begins. ‘She has a really clear idea dramatically about how to pace that whole section. I found that you need to know where you’re aiming for; you shouldn’t be giving away the world with every fortissimo.’ He turns to the opening of the scene and Salome’s ‘Ah! Du wolltest mich nicht deinen Mund küssen lassen, Jochanaan!’ (fig 314). ‘The detail in that music is extraordinary, and if you can’t hear the basset clarinet and cellos, if you can’t hear everything in the texture, you’re too loud. And the effect of those accents in the brass with the immediate release – but which you want even earlier than Strauss writes – so that the melody in the violins comes across. It’s the weirdest thing to say, but it needs to feel like chamber music – even with a hundred players.’ He reflects further. ‘Just looking through it again reminds me that I really felt that my job, my role in this music, was to “present” it. And that’s not about being passive; it’s about letting the music be heard, letting the singer be heard on top of everything. Then the climaxes take care of themselves if you do what Strauss says. It’s very artisanal work, in a way!’

We cover several details, but I can’t help noticing the evident care Gardner has taken with the small violin gesture – a sighing, moaning, or a mixture of both – that crops up between figs 355 and 357, accompanying Salome’s first words after the brief final interjection by Herod and Herodias. ‘Oh my God,’ he says, ‘that gives me the chills just looking at it. It’s so horrific. You can tell I marked it up more than pianissimo and made them slide between the notes. It’s so dirty.’ He makes a noise of shuddering disgust. ‘But I love it. I had to hear that!’

That moment marks the beginning of the opera’s end, as Strauss moves the scene towards its scrunching climax. ‘By the time you get to fig 359 all bets are off,’ Gardner explains. ‘I remember getting the most delicate thing I could possibly get in the context at fig 360, but then you’re overwhelmed. That awful harmony in the bar before 361 [the bar after Salome completes her final phrase] with those trumpets.’ He pauses briefly. ‘My God! Strauss had to be cold-blooded to write that bar. It’s disgusting. But to do that to himself – wow, what a person!’