Lager frozen in order to remove excess water (3,4)
I believe the answer is:
ice beer
'lager' is the definition.
(I know that ice beer is a type of lager)
'frozen in order to remove excess water' is the wordplay.
I cannot really understand how this works, but
'frozen' could be 'ice' (I've seen this in other clues) and 'ice' is found in the answer.
The remaining letters 'beer' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for ice beer that I've seen is " strong drink".)