Two fifths of Chardonnay, a half of coke and a quarter of alcopops needed for barbecue (8)
I believe the answer is:
charcoal
But I can't explain it at all! Could you help me understand?
(Other definitions for charcoal that I've seen before include "Black residue of burnt wood" , "Artist's black material" , "It's made by burners for use in burners" , "It's used in drawing and barbecues" , "Kind of fuel made by burning wood" .)