Wine in endless session, more savoury (7)
I believe the answer is:
tastier
'more savoury' is the definition.
('tasty' can be a synonym of 'savoury')
'wine in endless session' is the wordplay.
'wine' becomes 'asti' (I've seen this before).
'in' indicates putting letters inside.
'endless' means to remove the last letter.
'session' becomes 'term'.
'term' with its last letter taken away is 'ter'.
'asti' put into 'ter' is 'TASTIER'.
(Other definitions for tastier that I've seen before include "Having a more pleasant flavour" , "More attractive" , "More palatable" , "More appetising" , "More flavoursome" .)