Porridge base (4)
I believe the answer is:
oats
'porridge base' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oats that I've seen before include "Cereal for porridge" , "A cereal crop" , "Young men sow wild ones" , "Food for horses and Scots (said Dr Johnson)" , "Wild ones are sown in youthful excess" .)