Lots of cold-hearted soaks (7)
I believe the answer is:
batches
'lots' is the definition.
('batch' can be a synonym of 'lot')
'cold-hearted soaks' is the wordplay.
'cold' becomes 'ch' (I can't explain this - if you can you should believe this answer much more).
'hearted' indicates putting letters inside (some letters go to the heart of the word).
'soaks' becomes 'bates' (bating is a kind of soaking).
'ch' inserted into 'bates' is 'BATCHES'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for batches that I've seen before include "Quantities of goods produced at the same time" , "Numbers of loaves baked at the same time" , "Collections of things to be handled together" .)