But as it cools the gasses reintegrate. So I'm not sure the science backs this up. Water at the same temp should have the same amount of dissolved gas regardless of how it got to that temp (given enough time for the gas to reintegrate).
I think you're incorrectly discounting that time aspect. If you leave a glass of tap water sitting out, eventually there will be a bunch of bubbles clinging to the sides of the glass. This doesn't happen immediately, but rather over many hours. Similarly, I would think that boiling water won't reach its gas equilibrium during the course of making tea, but hot water sitting around waiting to be used will.
I agree with this. I develop my own film and the way I manage water is to boil it, put it into sealed bottles, and store those in the fridge. This avoids bubbles more readily than just using tap water (which is over 20C in the summer anyway, which is why I do the refrigeration thing). No, I don't have an aerator on my tap either. Obviously that introduces a lot of bubbles.
