Rather too much to soak (5)
I believe the answer is:
steep
'soak' is the definition.
(steeping is a kind of soaking)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for steep that I've seen before include "Sheer, precipitous" , "Difficult" , "Precipitous - exorbitant" , "Lofty" , "over the top" .)