Compensate for bad batch (6)
I believe the answer is:
offset
'compensate for' is the definition.
(I've seen this in another clue)
'bad batch' is the wordplay.
'bad' becomes 'off' (eg meat that's gone off is bad).
'batch' becomes 'set'.
'off'+'set'='OFFSET'
(Other definitions for offset that I've seen before include "Amount by which something is out of line" , "Compensate(d) for" , "Distance out of line" , "Compensation; printing technique" , "Compensation - printing process" .)