The country's most famous living author launched the attack on social networks and modern technology in an interview in which he said the idea of being constantly contactable - and possibly under surveillance - was "abhorrent".
He was speaking in an videoed interview for the Louisiana Museum of Modern Art in Humlebaek, Denmark, in cooperation with the German political website Cicero Online.
The 85-year-old, who won the Nobel Prize for Literature in 1999, said he was surprised more people had not walked away from Facebook and social networks since the NSA scandal revealed a mass online surveillance programme by US and British secret services.
“With the latest findings in mind, it surprises me that millions of people do not distance themselves from Facebook and all that crap, and say, "I want no part of it."
Grass said that he talked to his eight children and 18 grandchildren about Facebook which had led to his dislike of it. He said: “I do have certain reservations when one of them tells me I am on Facebook…I have 500 friends. I say someone who has 500 friends has no friends.”
The author said that virtual and online experiences could be no substitute for direct experiences.
“I feel a bit like a dinosaur,” he admitted. “I still write my manuscripts by hand. Then I type them up on my old Olivetti typewriter. There's no computer in my study. I don’t even have a mobile phone."
He added: "If I want information I make the effort and do research. I look things up in books, in the library. I know it's all a bit slower - and modern tools can speed things up. But literature for example... You can't speed it up when you work with it. If you do, you do so at the expense of quality."