Understand about beer — is into it (7)
I believe the answer is:
realise
'understand' is the definition.
('understand'->'realize' is in my internal thesaurus and 'ize'->'ise')
'about beer is into it' is the wordplay.
'about' becomes 're' (regarding).
'beer' becomes 'ale' (I've seen this before).
'into it' is an insertion indicator.
'ale' enclosing 'is' is 'alise'.
're'+'alise'='REALISE'
(Other definitions for realise that I've seen before include "Come to be aware" , "Figure out" , "Become aware of something" , "Grasp" , "produce" .)