Creatine Monohydrate causes water storage, which is one of the major benefits to creatine. Anything with caffeine (which is a diuretic) is going to send the body the message to empty extra water stores. This is especially true with coffee, which has high amounts of caffeine. Daddy has a good idea, but I would be sure to wait about 30 minutes before consuming the creatine. This way, you have the benefit of the dialated blood vessels from the caffeine, and the extra water storage from the creatine.