Series of notes in small capitals on drinks (6)
I believe the answer is:
scales
'series of notes' is the definition.
(musical scales)
'small capitals on drinks' is the wordplay.
'small capitals' becomes 'sc' (abbreviation used in printing).
'on' means one lot of letters go next to another.
'drinks' becomes 'ales' (ale is a kind of drink).
'sc'+'ales'='SCALES'
'in' acts as a link.
(Other definitions for scales that I've seen before include "Fish flake or weighing device" , "Set of musical notes - balanced on a fish?" , "though it's not Pisces" , "Sets of musical notes - balanced on a fish?" , "Climbs the weight measuring device" .)