Creatine works better in a liquid form.
In fact, in liquid form, you may not even be getting creatine, but creatinine, a by-product of creatine breakdown. Creatine, in powder form, is extremely stable. When exposed to an acidic environment or moisture for a long time, creatine will begin to break down into worthless creatinine. The citric and phosphoric acids found in many liquid creatines, which are used to preserve the shelf life of these products, actually helps break creatine down. So as a rule of thumb, if you're going to make a creatine shake, drink it by the end of the day.