I think you are assuming that all "vessels" absord heat at the same rate.
Even if you don't pre-heat the vessel by pouring boiling water in it, its
temperature may vary a great deal. A thick, cold mug is going to pull the
temperature down a lot further than a warm bone china teapot!
"Tom Blorst" wrote in message
om...
Hi Everyone,

I've been conducting an experiment with water temperature lately, and
have gotten some results that surprised me.

In brief, I've always had a problem that many others here have
mentioned -- how to estimate the temperature of water (mainly for
sensitive green teas) without resorting to a thermometer.

A method that had been working well for me was to pour boiling water
into a mug and let it sit for a minute or two, then add the leaves. I
figured this would get the temperature down to about 180F, and it
seemed to work great.

One day, though, I decided I'd actually check to see what kind of
temperatures it was producing, and, when I got the thermometer out, I
found that it was more like 150F. So I tried pouring water into a
cold mug, waiting a few seconds (basically just long enough for it to
heat the mug), then taking the temperature. I found that even boiling
water (212F, since I'm at sea level here) drops almost immediately to
about 170F when poured into a room-temperature vessel, and this 170F
figure is consistenly repeatable. This seems awfully low -- is my
thermometer broken?

I've always read (and, of course, believed) that you lose about 10
degrees F to the heating of the vessel, but it's looking like I'm
losing a lot more. If anyone else can duplicate these results, I can
see at least two consequences it would have:

1) It underscores the importance of pre-heating the cup/pot for black
teas that really do need 195F-plus water, which is a step that I've
often skipped in the past.

2) It makes the preparation of 170-180 degree greens much easier --
just let the water boil, pour it into the vessel, wait a minute, and
add the leaves.


Any thoughts?

"juanon" writes:

Even if you don't pre-heat the vessel by pouring boiling water in it, its
temperature may vary a great deal. A thick, cold mug is going to pull the
temperature down a lot further than a warm bone china teapot!

Of course you are correct as you state this. But a thick, cold mug will hold
heat longer than a thin bone cup or pot. It's a matter of rate of heat
transfer. In the long run, the tea will reach ambient temperature; it will
get there more quickly with a thin vessel. There is no possibility of it
becoming colder than that (unless the vessel was pre-chilled, and I assume
that is not the case).

This time of year our kitchen is chilly in the morning, and when I make my
Irish Breakfast (same blend for probably ten years now) and pull a cold cup
out of the cabinet, I'm needing to heat extra water for that pre-heating of
both pot and cup.