Riotous satire about new drink (7)
I believe the answer is:
'drink' is the definition.
(I know that Retsina is a wine)
'riotous satire about new' is the wordplay.
'riotous' indicates anagramming the letters.
'about' indicates putting letters inside.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'satire' is an anagram of 'retsia'.
'retsia' going around 'n' is 'RETSINA'.
(Other definitions for retsina that I've seen before include "Greek wine - nastier sort" , "Flavoured Greek white wine - nastier brand" , "Type of Greek wine" , "Oily-tasting Greek white wine" , "Greek white wine flavoured with resin" .)