Okay, five hours later. The water is about 3/4 of an inch low. The water is cold and stirring causes some fizzing, but no heat is released when stirring. Pouring the water out of the cup revealed that the QC looked the same as when it was poured in. Exposure to air caused no reaction. All in all, a rather boring experiment.
"If ye love wealth better than liberty, the tranquility of servitude than the animated contest of freedom, go from us in peace. We ask not your counsels or arms. Crouch down and lick the hands which feed you. May your chains sit lightly upon you, and may posterity forget that you were our countrymen!” - Samuel Adams