Gas — more than enough bottles (6)
I believe the answer is:
ethane
'gas' is the definition.
(ethane is a gas)
'more than enough bottles' is the wordplay.
'bottles' indicates a hidden word (bottling is a kind of containing).
'ETHANE' is hidden in the letters of 'more than enough'.
(Other definitions for ethane that I've seen before include "Flammable gas; eat hen (anagram)" , "Flammable hydrocarbon" , "Chemical" , "Ate hen (anag) - hydrocarbon gas" , "Fuel" .)