Quantity of wine? Chat with son involves litre (5)
I believe the answer is:
glass
'quantity of wine?' is the definition.
'glass' can be an answer for 'quantity' (glass is a kind of quantity). I am not sure about the 'of wine?' bit.
'chat with son involves litre' is the wordplay.
'chat' becomes 'gas' (informal term meaning to chat).
'with' is a charade indicator (letters next to each other).
'son' becomes 's' (genealogical abbreviation for son).
'involves' means one lot of letters goes inside another.
'litre' becomes 'L' (abbreviation).
'gas'+'s'='gass'
'gass' placed around 'l' is 'GLASS'.
Can you help me to learn more?
(Other definitions for glass that I've seen before include "(Material used in) mirror" , "Watch-face cover" , "Perhaps schooner" , "Eg, tumbler" , "Calm lake may be compared to this" .)