Prepare, as coffee (4)
(Other definitions for brew that I've seen before include "Make, eg, beer" , "Mixture" , "Cup of tea (informal)" , "Concoction" , "Prepare by boiling and infusing" .)
(Other definitions for percolate that I've seen before include "Sift gradually through clear poet" , "Strain" , "Penetrate gradually" , "Filter - to replace (anag)" , "Pass through fine openings, like coffee say" .)