I’m a dogged patron of coffeehouses. You have to have time on your hands here, just as you do when you’re making or playing music, and then your soul can just wallow. I like the idea of people living in this café, as there were a century ago. At home you sleep, but in the coffeehouse you live. Some people had their mail delivered here and made their pension over to the landlord. And when he’d settled their bills, he handed them what was left over as pocket money. For me, Einstein’s local in the Kurfürstenstraße is the nicest café in Berlin. It’s part and parcel of my life in Berlin. I moved here in 1987 and stumbled on the place a fortnight later. The same waiter served me for thirty years. Whatever area of the city I’m living in, I come here once a month and order my double mocha with whipped cream.

Or two. In all that time I was never treated badly – that’s got to be a record! For me, the Einstein is reminiscent of string instruments with sordines, soft chords, horn, bassoon, bass clarinet. Maybe it’s the brown wood panelling and the muffled level of noise. This coffeehouse is the only spot where music comes to me in spite of the barrage of different noises. You’re in a crowd but still kind of on your own. I like people-watching. There was a time when I used to sit here jotting down my impressions in a notebook.

When two people are having an argument, I study their gestures. In a way it’s music in motion. I’ve just finished writing OCEANE for the Deutsche Oper Berlin, an opera based on Fontane’s fragment “Oceane von Parceval”. Fontane lived on Potsdamer Straße, just around the corner from Einstein. His Oceane material dates from around 1880, just like this villa. Maybe he even used to walk by here.

Oceane is a modern Melusine. Fontane had a thing about these mythical creatures, who were at odds with their surroundings. His interest may have been because of his daughter, an intelligent but socially maladjusted young woman. He worried that she might harm herself in some way – and so it was to be. Many years later, after Fontane’s own death, she committed suicide.

Fontane’s fragment is not packed with action, so I really had to get inside the characters to reveal their drama. The key tones in Oceane are a broken D major chord and a bunch of spaltklänge, high and low tones with nothing pitched in the middle. The main character is out of kilter, while her male antagonist, Martin von Dircksen, chimes with complete chords in the middle ground. Acoustically, it’s quite clear that the two characters are not compatible. The story points up a clash of two cultures similar to the clash over the foundation of the German empire, which Fontane loathed. He represented the modest side of Prussia and reviled Bismarck and the callow, arrogant Germany with its aspirations of grandeur and urge to make a splash. Such is the nature of Martin von Dircksen, who is set on marrying and building up a farming empire. This all leaves Oceane cold. She is Fontane’s antithesis to the idea of a technology-based age. She loves the sea, is one with nature, is quiet and aloof. On the other hand, she’s a wild dancer, guzzles huge quantities of water and tears off her clothing.

“This woman’s way of behaving is very different to ours. Which means she can never truly be one of us,” says the Pastor in the opera: “And you want to make babies with that?” Oceane is passionate but does not yet know how it feels to be in love – and is weighed down by that fact. “Nothing in the earthly realm could give me what I needed,” she says, “so I’m leaving.” When Oceane walks into the sea at the end, she’s going home.