Bitter beers (4)
'bitter beers' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ales that I've seen before include "Alcoholic drinks" , "Types of beer" , "A sale of beers" , "What might be delivered by pumps" .)
(Other definitions for porters that I've seen before include "They fetch and carry" , "They carry luggage and supplies" , "Luggage carriers" , "They carry luggage etc." .)