Ale supplier having bartender empty pitcher (6)
I believe the answer is:
brewer
'ale supplier' is the definition.
'bartender empty pitcher' is the wordplay.
'empty' says to hollow out the word (remove centre letters).
'pitcher' becomes 'ewer' ('ewer' can be a synonym of 'pitcher').
'bartender' with its centre taken out is 'br'.
'br'+'ewer'='BREWER'
'having' is the link.
(Other definitions for brewer that I've seen before include "Bitter maker?" , "I make tea" , "work I supply to pubs" , "Beer-maker" , "Ale manufacturer" .)