Rang understudy back about beer (6)
I believe the answer is:
pealed
'rang' is the definition.
(pealing is a kind of ringing)
'understudy back about beer' is the wordplay.
'understudy back' becomes 'ped' (I am not sure about this - if you are sure you should believe this answer much more).
'about' means one lot of letters goes inside another.
'beer' becomes 'ale' (type of beer).
'ped' enclosing 'ale' is 'PEALED'.
Can you help me to learn more?
(Other definitions for pealed that I've seen before include "Sounded like the loud ringing of bells" , "Rang out loudly" , "produced claps" .)