Use whatever liquid you want to try and enhance your flavors the most. I've done it with apple juice, beef broth, chicken broth, grape juice, pineapple juice and water....
I've had great success using it and the judges don't seem to be able to notice the flavors... At least they haven't said so for my products that I am turning in....
FROM SEA TO SHINING SEA BBQ TOUR
Red Jambo one off
Homer Simpson 22 " Weber Kettle
Red 18 1/2" Weber Kettle
Black 26 3/4" Weber Kettle