How many people are celebrating the fact that, last week, one of Europe’s most inspired writers about music, modern art and aesthetics celebrated his 90th birthday? The answer is relatively few, which might seem surprising. He is a world-renowned authority on the grotesque and the absurd — territory through which he darts mischievously in his poems, originally composed in his native German. But you have to turn to his essays written in English to experience his refined sarcasm, which is either delicious or mortifying, depending on whether you feel incriminated by his strictures against intellectual laziness. He is quirky and rigorous — a combination associated with his beloved Dada, a movement I’d written off as an embarrassment until I read his dazzling essay on the subject in the New York Review of Books.

And yet, as I say, his writings aren’t attracting the attention they deserve as he turns 90. That’s because he is Alfred Brendel, the revered Austrian interpreter of the piano music of the Viennese masters. The media will inevitably focus on his recorded legacy. The tributes won’t be as easy to write as, say, birthday salutes to Rubinstein or Horowitz. That’s because Brendel, who retired from playing more than a decade ago, was always determined not to project his own personality from the keyboard.

Ironically, his fidelity to the composer’s markings led some critics to claim that his trademark was a certain didactic fussiness. You can work out where they got this idea, if you search hard enough among the 114-CD set of Brendel’s Philips recordings. But I despair of anyone who thinks he’s defined by the occasional whiff of overthinking. I’ve met a few Brendel-haters in my time; they tend to be either tiresome evangelists of ‘period practice’ or old queens whose idea of perfect pianism is Horowitz in Liberace mode.

Alfred Brendel’s central achievement has been to give us authoritative readings of almost the entire piano music of Mozart, Beethoven and Schubert, together with the best of Haydn and Liszt. Authority may be in the ear of the listener, but it’s surely significant that so many music lovers hear a remarkable quality in his playing: the ability to reconcile structure and spontaneity by mimicking the phrasing naturally employed by singers.

That’s too subtle a skill to make his sound instantly recognisable, and I suspect Brendel would be appalled if it did. But his writing could never be mistaken for anyone else’s. Only he could have written the glorious poem in which Mozart discovers Beethoven is black.

Brendel’s writing, unlike his nobly self-effacing recordings, hints at a slightly scary personality. He may relish the calculated absurdity of Dada, and he lists as a hobby the search for ‘unintentional humour’, but he won’t tolerate mediocrity or pointless vulgarity, especially in dead composers. His pet hates include Reger (‘given the choice of playing his piano concerto and dying, I’ve always thought I’d prefer to die’) and Rachmaninov. As a young man, he played Rachmaninov’s Second Piano Concerto, but concluded that his music was ‘a waste of time’.

For Brendel, Rachmaninov is tainted by kitsch. He argues that in the early 20th century ‘there existed a Bermuda Triangle between Puccini, Rachmaninov and Lehar, in which primary, genuine, noble emotions were in dire danger of being sucked away’. Yet he doesn’t despise all varieties of kitsch. In The Veil of Order, a book-length series of interviews with Martin Meyer, Brendel quotes Milan Kundera’s theory that the ‘second-hand emotions’ generated by kitsch made possible the concept of the brotherhood of man. But he felt that the Czech novelist underestimated the ingenious range of kitsch. ‘There is also a scatological genre of kitsch. Kundera denies this, but I could show him some postcards.’

I’m sure he could.