Certain to tuck into alcohol in a responsible manner? (8)
I believe the answer is:
measured
'in a responsible manner?' is the definition.
'certain to tuck into alcohol' is the wordplay.
'certain' becomes 'sure' (synonyms).
'to tuck into' means one lot of letters goes inside another.
'alcohol' becomes 'mead' (mead is a kind of alcohol).
'sure' placed into 'mead' is 'MEASURED'.
(Other definitions for measured that I've seen before include "Determine dimensions" , "Weighed" , "certain content of alcohol" , "Deliberate, restrained" , "Found the size or quantity of something - using tape or ruler" .)