Servant who can provide his own beer (5)
I believe the answer is:
valet
'servant' is the definition.
(valet is a kind of servant)
'provide his own beer' is the wordplay.
'provide his' becomes 'vt' (I can't explain this - if you can you should give a lot more credence to this answer).
'own' indicates putting letters inside.
'beer' becomes 'ale' (type of beer).
'vt' placed around 'ale' is 'VALET'.
'who can' acts as a link.
Can you help me to learn more?
(Other definitions for valet that I've seen before include "Clean (a car); attendant" , "Personal serving man" , "Male servant" , "Man's servant" , "Man's manservant" .)