Drink containing old grape (5)
I believe the answer is:
pinot
'grape' is the definition.
(I know that Pinot is a type of Vitis vinifera)
'drink containing old' is the wordplay.
'drink' becomes 'pint' (pint is a unit of liquid volume).
'containing' means one lot of letters goes inside another.
'old' becomes 'o' (abbreviation as in OT - Old Testament).
'pint' placed around 'o' is 'PINOT'.
(Other definitions for pinot that I've seen before include "Wine-making grape" , "drink" , "Kind of wine grape" , "Variety of grape used for Burgundies and champagnes" , "Variety of wine grape" .)