Effervescent beer (5)
I believe the answer is:
lager
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">effervescent beer</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for lager that I've seen before include "African camp" , "A brew" , "Light beer needed" , "Light-coloured beer" , "Lout's drink?" .)