Hmmmm. This calls for SCIENCE!
I'm thinking of a test vessel kind of like those glasses that are double-hulled and have the freezing medium in that void space between. We could exhale the vapour into the vessel and measure how much gets reconstituted.
The one hitch is that we need a completely dry environment to test in, so that no ambient humidity condenses in the vessel. Oh, and we'd need a camel to blow the vapour into the vessel, to reduce any potential water in the exhalation. That means we'd need to train a camel to vape. I wonder how expensive camel trainers are per hour....
Imagine getting THAT research grant across your desk.