Brewing ale and demon drink (8)
'drink' is the definition.
(lemonade is a kind of drink)
'brewing ale and demon' is the wordplay.
'brewing' is an anagram indicator.
'and' says to put letters next to each other (I've seen this in other clues).
'ale' after 'demon' is 'demonale'.
'demonale' with letters rearranged gives 'LEMONADE'.
(Other definitions for lemonade that I've seen before include "Leo named oddly for a soft drink", "Flavoured mineral drink", "Sweet beverage of diluted juice", "Sweetened beverage of diluted juice", "Lead me on to the strange drink".)