Does water that's been left to sit and then reboiled taste different from fresh water boiled once? This may sound like a silly question, but I've always wondered:
If I boil some water and use some of it and leave the remainder in the kettle, and then a few days later boil that same water again, will it taste the same as if I'd emptied the old water and boiled fresh new water?
I've got a habit of emptying the kettle water and starting with fresh water to boil when I prepare my coffee (using a French press), and I'm wondering if there's no good reason to do that.
For what it's worth, the kettle has a top (so I'm ruling out dust as a concern), and the water I'm boiling is tap water that's been through a Brita filter in a jug.
If the taste is different, what's the chemical or physical justification?
Yes, it is different. Two things happen: the dissolved oxygen boils out, and whatever mineral solids are in there become concentrated as steam evaporates.