Spirit had very good finish when stored in oak flakes (5)
I believe the answer is:
vodka
'spirit' is the definition.
(I know that vodka is a type of spirit)
'very good finish when stored in oak flakes' is the wordplay.
'very' becomes 'v' (abbreviation).
'good' becomes 'ok'.
'finish' means to remove the first letter.
'when stored in' means one lot of letters goes inside another.
'oak flakes' becomes 'oda' (I am not sure about this - if you are sure you should believe this answer much more).
'ok' with its initial letter removed is 'k'.
'k' placed within 'oda' is 'odka'.
'v'+'odka'='VODKA'
'had' is the link.
Can you help me to learn more?
(Other definitions for vodka that I've seen before include "Russian tipple" , "Spirit traditionally made from fermented grains or potatoes" , "Colourless liquor" , "Basis of a Bloody Mary" , "Russian liquor" .)