Infuse fermented herb tea (7)
I believe the answer is:
breathe
'infuse' is the definition.
(thesaurus)
'fermented herb tea' is the wordplay.
'fermented' indicates an anagram.
'herb'+'tea'='herbtea'
'herbtea' anagrammed gives 'BREATHE'.
(Other definitions for breathe that I've seen before include "Do this before you go under" , "Take in 30" , "Inhale/exhale" , "sigh" , "Take inspiration" .)