LowInFat wrote:I've heard some mixed opinions regarding how water that's been boiled too long/re-boiled affects tea. Apparently whenever water is boiled, oxygen evaporates, leaving the tea brewed from said water tasting flat. Frankly, I don't see the logic behind this. If the oxygen is boiled out, doesn't that just leave hydrogen on its own, which isn't even water? If this is a misconception, does re-boiling water affect the tea in any way? If it isn't, can someone explain the chemistry behind it?
I tried searching for existing threads but couldn't find any.
I was going to let someone with more chemistry knowledge than me speak up. But when we talk about the oxygen leaving the water, we are not talking about the oxygen in the water molecules themselves, but rather there are other gases in gas form so to speak dissolved into the water. So there is some oxygen, nitrogen, carbon dioxide even inside the water itself. Again not the water molecules but you can imagine molecules of Oxygen, nitrogen and the like floating around among all the water molecules.
A way to think about this is if you've seen those gels that have bubbles or other little beads floating in them, its very similar to that except on a much smaller level. Where the gas molecules that the place of the bubbles or the beads, and the water is the gel.
Now yes the dissolved gases work their way out when boiled, but if the kettle sits for awhile some will naturally start to work their way back in slowly. And I have a hard time completely believing that the water gets that dead, as the turbulence of the pouring of the water in the brewing should introduce a good bit of air back into the water right before it is brewed. Granted I do not have the equipment to be able to run any sort of test to see how much it would be off.