It's instrumental in having wine around (8)
I believe the answer is:
clarinet
'it's instrumental' is the definition.
(clarinet is a kind of musical instrument)
'having wine around' is the wordplay.
'having' becomes 'in' (I can't justify this - if you can you should believe this answer much more).
'wine' becomes 'claret' (claret is a kind of wine).
'around' means one lot of letters goes inside another.
'in' placed inside 'claret' is 'CLARINET'.
'in' is the link.
Can you help me to learn more?
(Other definitions for clarinet that I've seen before include "Find an instrument in claret" , "musician" , "member of orchestra" , "Wind instrument made from Clare tin" , "Instrument in claret, strangely" .)