Re: Why? Does water go off?
Depends how long you leave it.
LOL at that.
Boiling the same water several times must also affect its mineral content in ways that are detrimental to what your palate is used to.
I wasn't really thinking about multiple boils, more that it's just sitting in the pipe or just sitting in the kettle and how little difference that could make. If you are in an area where the chlorination is detectable, leaving it standing in the kettle will outgas the chlorine. Maybe boiling it "fresh" will too.
But, since you mention multiple boils of the water, I wonder if that really makes any difference? And if it does, does it matter where the water came from in the first place? Many years ago our local water came from an underground reservoir and was "hard", ie from under the limestone hills These days it comes from a stonking great man made reservoir filled by rain and whatever is picked up as it runs on/over/under the ground to get there but is not hard. No kettle fur here any more.