Large beers toff unwrapped during American garden event (5,2,3)

'large beers' is the definition.
(large measures of beer)

'toff unwrapped during american garden event' is the wordplay.
'unwrapped' indicates the central letters (the letters which wrap the word are removed).
'during' is an insertion indicator.
'american garden' becomes 'yard' (US term for a garden).
'event' becomes 'sale' (promotional event).
The central letters of 'toff' are 'of'.
'yard'+'sale'='yardsale'
'of' put inside 'yardsale' is 'YARDS OF ALE'.