From what I could tell (and I'm still ascending the Ric Olie Observation Tower, to the point at which C3PX's mob funding ran out, so my observations are somewhat limited) The ice in the bathtub was water, but the liquid was slightly watered down whiskey. I did take time to note, however, that the whiskey level did not change as the ice melted.

Ferris- I'm glad to know that you think that ABC is a horrible horrible man even if it's based on his mad attempts to freeze whiskey as opposed to the little detail of the fact that he drugged me and stole my kidneys!