Friend adjusted tea to taste (6)
I believe the answer is:
palate
'to taste' is the definition.
(palate can mean an ability to distinguish tastes)
'friend adjusted tea' is the wordplay.
'friend' becomes 'pal' (pal can mean a friend).
'adjusted' indicates an anagram.
'tea' anagrammed gives 'ate'.
'pal'+'ate'='PALATE'
(Other definitions for palate that I've seen before include "One may savour" , "Liking" , "Sense of taste at roof of mouth" , "A plate (anag.)" , "Roof of the mouth, seat of taste" .)