Here's the source Wikipedia gives: lazyka.com. My impression is that the blurbs below are verbatim clips from the liner notes of various releases.

THE CAPITOL COLLECTORS SERIES:
"Scotch And Soda" is actually from the group's first LP, "The Kingston Trio," though for some reason it was not released as a single until four years after the album came out, on April 9, 1962. The song has a history all its own: In 1954 Bob Shane and Dave Guard went to Fresno for Easter to Visit Dave's girlfriend, Katie Seaver. Katie turned out not to be at home, but her parents and 11-year-old brother entertained the boys. Mrs. Seaver played piano while her husband sang a song from their honeymoon in 1934. Four years later, Dave revised the tune for the Trio, and Bob sang it. It was subsequently covered by The Manhattan Transfer on their 1976 album, Coming Out. (And Katie's little brother grew up to be baseball great Tom Seaver.)

THE CAPITOL YEARS set:
Master #18389A added to the Capitol archives December 14, 1958
Previously unreleased
Now considered the ultimate saloon song, "Scotch And Soda" was already an oldie when Dave and Bob first heard it In 1953. They were on a pre-Trio double date and Dave's dates parents {whose most famous offspring became baseball great Tom Seaver) played them a memorable song they'd heard at a hotel piano lounge on their honeymoon. When the time came to record the Trio's first album, Dave worked up an arrangement for Bob's solo. After nearly five years of pleas from DJs, Capitol released "Scotch and Soda" as a single In 1962. The version Included here is the earliest known live recording of the song, another previously unreleased selection from the STEREO CONCERT tapes. Today "Scotch And Soda" is still Bob's favorite Trio tune and the identity of the original composer still remains a mystery.

THE KINGSTON TRIO: THEIR GREATEST HITS AND FINEST PERFORMANCES
Rarely did a Trio member have a whole solo, but this memorable ballad spotlights Bob Shane's grainy voice. "Scotch and Soda," written by Trio member Dave Guard, came from their first LP, The Kingston Trio (1958), but Capitol waited four years to release it as a single. Although it climbed no higher than No. 81, the song has always been a big favorite of Trio fans, including The Manhattan Transfer, who sang it on their 1976 LP Coming Out.


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