More stout and ale, drinking large one (8)
I believe the answer is:
portlier
'more stout' is the definition.
('portly' can be a synonym of 'stout')
'ale drinking large one' is the wordplay.
'ale' becomes 'porter' (porter is a kind of ale).
'drinking' is an insertion indicator (inserted letters are consumed or drunk).
'large one' becomes 'li' (I can't explain this - if you can you should believe this answer much more).
'porter' enclosing 'li' is 'PORTLIER'.
'and' acts as a link.
Can you help me to learn more?
(Other definitions for portlier that I've seen before include "Larger" , "more stout" .)