By Adam Perry Lang from his book Serious Barbeque.
1/4 C Prepared yellow mustard
1/4 C Water
1 T Worchestershire Sauce
1 T Apple Cider vinegar
Used first time 6/18/16 on Loin and Spare Ribs. Loins had a nice bark from this added on top of My Rub. Could not say it made a difference from straight yellow Mustard.