Set a test for flavour (5)
I believe the answer is:
taste
'for flavour' is the definition.
(I've seen this before)
'set a test' is the wordplay.
'set' indicates an anagram (instruction to set the letters).
'a'+'test'='atest'
'atest' anagrammed gives 'TASTE'.
(Other definitions for taste that I've seen before include "Small sample of food" , "The ability to discern good quality" , "gains experience" , "Experience - discrimination" , "Nice distinction felt in the mouth" .)