Lyric discussion by pumkinhed 

Cover art for Ocean Spray lyrics by Manic Street Preachers

i don't quite understand the purpose of the grungey guitar bit after the choruses.

Regarding the grungey guitar bit, I think it's because even though he wants the drink to hlep her he knows it won't, so the guitar is showing his frustration at not being able too much of a difference. Perfect example of why I love the Manics, using guitars to escape the sadness.