Composer who confused beer with whiskey (5)
I believe the answer is:
weber
'composer' is the definition.
(Carl Maria von Weber was a German composer)
'confused beer with whiskey' is the wordplay.
'confused' indicates an anagram.
'with' indicates putting letters inside.
'whiskey' becomes 'w' (alpha bravo charlie delta ...**).
'beer' is an anagram of 'eber'.
'eber' placed around 'w' is 'WEBER'.
'who' acts as a link.
(Other definitions for weber that I've seen before include "bit of magnetism" , "German composer of Der Freischutz" , "physics unit" , "Unit of magnetic flux, composer" , "Founder of the German Romantic school of opera, d. 1826" .)