The wine tasting bit (4)
I believe the answer is:
asti
'the wine' is the definition.
(I've seen this before)
'tasting bit' is the wordplay.
'bit' indicates the answer is hidden within the clue.
'ASTI' is hidden within 'tasting'.
(Other definitions for asti that I've seen before include "town in Italy" , "It's a (anag) - wine" , "Italian drunk" , "Sparkling white wine" , "Sparkling drink" .)