Cecil said:
This is true, but you should never make tea (or any drink that requires
hot water) from reboiled water, as the removal of most of the dissolved
oxygen from the water during the first boiling makes the water taste
awful - and your tea ever more so. That’s why water from an urn (as
many offices have) always makes shite tea.
So… ALWAYS boil fresh water - only as much as you need - each and every time! 
So the first boiling removes the dissolved oxygen, yet somehow its influence is still there when you make tea from it? How is it that the problem appears only when it’s boiled a second time?
Tea connoisseurs will tell you that you must not boil your water for tea. You must remove it from the heat immediately before it begins to boil. They even sell special little devices that you put in your tea kettle which rattle when the bubbles begin forming on the bottom – but before the water reaches a full boil.
Personally, I cannot tell the difference.
I make awesome tea (It’s my superpower, seriously. Ask anyone who knows me.) and I’ve never noticed a difference between once-boiled or twice-boiled water. Or four-times boiled for that matter (I get distracted a lot).
Sorry, I made my point poorly. :smack:
What I meant was this: Boiling water removes SOME of the dissolved oxygen -
reboiling removes MORE and it’s this that affects the taste. Reboiling AGAIN
will taste even worse.
Sure, there are those who say they’ve never noticed a difference, but that
doesn’t mean there isn’t a difference in taste, it simply means that these
poor people are unable to tell the difference. This could be due to a poorly
developed palate, a lack of observational skills or perhaps they’re
smokers (or just ‘simple’?) who knows?
The thing is, we need to be VERY wary of the lazy, illogical, existential notion of
“If I didn’t see it/touch it/taste it, then it doesn’t exist”. My mother lived in Romania
during the '50s and SWORE there was no Russian influence in Romanian politics,
and NO Hungarian revolution - simply because she (a) saw no Russians, and (b)
heard nothing about the uprising in Budapest.
Facts are facts, perceptions can lead us to facts, but they are not facts themselves.
Anyway, if you’ve REALLY not noticed it, try this test.
(1) Fill a cup with cold tap water. Put it to one side and label it (A)
(2) Boil some water.
(3) Fill another cup with this water. Label it (B)
(4) Reboil the remaining water.
(5) Fill another cup with this water. Label it (C)
(6) Leave all cups to cool.
(7) When all cups are at the same room temperature, drink from each one.
(8) Each cup WILL taste differently. The boiled water will most likely taste flat,
dead, dull. (A) will taste better than (B) and (B) will taste better than (C).
(9) If you still don’t notice a difference, might I suggest you never ever
eat at good restaurants or buy good quality food. There’s no point, it’s
wasted on you! 
NOTE: It’s important to note that we’re talking about dissolved oxygen, and not the oxygen that makes up the H2O molecules. 
And I’ve never noticed the curvature of the earth. I guess it must be flat after all!
Not the same thing, snarky man. And your “boiled water taste test” is irrelevant. What’s wanted is a BLIND taste test, by many people, using tea made from unboiled, boiled, and reboiled water, because the tea itself has a strong flavor. Not only that, you’d have to control for other things in the water like mineral content. I can hypothesize that some minerals, having been concentrated by the reboil, might actually make tea taste better, possibly depending on the type of tea.
Then there’s the problem of the cup of tea made from unboiled water. How long should it steep cold? Should it be drunk cold? Almost certainly not, but then how do we reheat it so as to be sure we lose no dissolved oxygen? Is the process of cold steeping significantly different than hot steeping such that there are other taste differences introduced?
We can agree that boiling and reboiling removes dissolved oxygen from water. As for the rest, unless one is a tea company, de gustibus…
Dang, Cecil, why’d you bring this up again?
I suspect the origin of the “hot water freezes faster” myth comes to us with the advent of the ice makers in refridgerators. I remember many years ago hearing a salesman telling a potential customer that he should connect the icemaker to the hot water supply because it would freeze faster. Yeah, right. It hadn’t been that long since I’d aced my high school physics so I figured an experiment was in order.
I went home and dumped the ice out of four trays, filled two with hot tap water and two with cold tap water then put then in the freezer. I repeated this several times placing the trays in various locations, and spaced the experiment over two days annoying tha crap outta my then wife.
Guess what. The cold water froze faster every time. By quite a bit. I was gonna go back and kick that salesman’s ass on principal, but little woman (this was back then) wouldn’t let me.
I guess that settles that!
Uhh, mangeorge… This article was about boiling, not freezing. That was a different column.
I shall apologize when Cecil Himself calls me out.
I am sure cold water boil much faster than hot one.
posted in wrong area and removed - sorry
To add onto this topic, there is are certain circumstances where hot water will freezer faster than cold water. It’s called the Mpemba effect.
I feel the need to chime in that I prefer once boiled water to never boiled water. Boiling removes the chemical flavors and gives it a cleaner taste to me. I agree with the noticeable change, but to some it’s for the better.
Is that “stowed”, Bob, or “stewed”?