So what is the purpose of the ice bath at the end of the smoking & cooking of sausage. ???
It is my understanding that when the IT is reached you give them an ice bath to stop the cooking to prevent fat out. Just as a brisket or butt will continue to "cook" when they are pulled, the sausage will also continue to cook. I am sure that one of the sausage pros will be by shortly to fully explain the ice bath and blooming process.
Sailor hit the nail on the head. You want the cooking process to stop once you've reached your target IT. The ice bath stops the cooking and rapidly cools the sausage. Then you want to hang it to dry (Blooming).