Wine produced by Irish county town's capital (6)
I believe the answer is:
claret
'wine' is the definition.
(claret is a kind of wine)
'by irish county town's capital' is the wordplay.
'by' is a charade indicator (letters next to each other).
'irish county' becomes 'clare' (I've seen this in another clue).
'capital' indicates taking the first letters.
The initial letter of 'towns' is 't'.
'clare'+'t' is 'CLARET'.
'produced' acts as a link.
(Other definitions for claret that I've seen before include "Purplish-red - blood" , "Alcohol" , "Irish county starts the wine" , "Deep purplish-red" , "Deep red colour" .)