Harrison, 54, donned reading spectacles to pore over large bundles of court documents as he gave evidence to stop an amateur recording of the group made at the beginning of their fame 36 years ago.
"Unlike the experts who wallow in Beatle trivia I spend a lot of time getting the junk out of my mind through meditation so I don't know or remember - I don't want to know or remember - every last detail because it was trivial pursuit," he said at one point.
Mr Harrison, Ringo Starr, Sir Paul McCartney and Yoko Ono, who is executrix of John Lennon's will, are asking a High Court judge to ban sales of a CD produced from the recording made at The Star Club in Hamburg in 1962.
In his evidence Mr Harrison told of the "wild early" days which involved "a lot of teenagers getting drunk playing rock'n'roll". He said: "That's how it was. It was just a wild thing."
The ex-Beatles and Yoko want the original tape at the centre of the case, or proof that it has been destroyed. It was made by Edward Taylor, leader of obscure Sixties band King Size Taylor and The Dominoes, on his own reel-to-reel machine when he was playing a double bill with the Beatles.
Mark Platts Mills QC, representing the Beatles, told Mr Justice Neuberger at the start of the case that there had been "various attempts to exploit" the tape by people associated with the defendants, Lingasong Music Ltd, of Waltham Abbey, Essex.
Lingasong is claiming that John Lennon, who was shot dead in 1980, gave his verbal consent to the recording, but the other group members say they did not even know it was being made.
Mr Harrison said that Ted Taylor was not a close friend. "He was a leader of another one of the groups. In those days, everyone was friendly to one another but only saw one another if they happened to play the same club at the same time."
Harrison then went on to talk candidly about The Beatles' early days. He said that Lennon was "like the loudest of us" and the eldest - before Ringo joined. "But we had a democratic thing going between us. Everyone in the band had to agree with everything that was done."
Harrison said the record at the centre of the case was the "crummiest" ever made in the group's name. "The only person who allegedly heard anything about it is the one person who is dead, who can't actually come here and say it's a load of rubbish."
He said John Lennon would have said something about the tape if he had known about it: "He never said anything to anyone. He didn't say anything to Brian Epstein or to Paul McCartney."
Even if anything had been said between John Lennon and Ted Taylor it did not constitute a business deal: "One drunken person recording another bunch of drunks does not constitute business deals."
The case continues