Liquid may start to curdle after utensil used to mix cocktail (6,3)
I believe the answer is:
whisky mac
'cocktail' is the definition.
(cocktail of whisky and ginger wine)
'liquid may start to curdle after utensil used to mix' is the wordplay.
'liquid' indicates anagramming the letters.
'start to' says to take the initial letters.
'after' means one lot of letters go next to another.
'utensil used to mix' becomes 'whisk' (kitchen utensil for mixing).
The initial letter of 'curdle' is 'c'.
'may' is an anagram of 'yma'.
'yma'+'c'='ymac'
'ymac' after 'whisk' is 'WHISKY MAC'.
(Other definitions for whisky mac that I've seen before include "Mixed drink" , "Drink with ginger wine" , "Chaser" .)