Re: Heat loss in brewing vessels

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 don't know, but in my experience a thermometer typically shows a drop of about 10 degrees F when boiling water hits a brewing vessel. Believe me, I've seen this *many* times.

What does your thermometer show when dipped into boiling water in a saucepan?

/Lew

Reply to
Lewis Perin
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For what it's worth:

It makes sense that a cold vessel with greater mass will absorb more heat from a cup of water poured into it than would either a cold vessel with less mass, or a preheated vessel of any mass. The ratio of "calories needed to heat the vessel" to "calories available in the tea steep water" is also probably less favorable when the water quantity is a cup as compared to a potful. Comparatively speaking, there'd not be as much heat available in the newly-added water proportionate to the mass of the heat-hungry vessel. That is, hotting a pot might draw off, say, 6% of the calories in the water, hotting a cup might draw off 13 or 14% of the calories in the water. (These are entirely made-up numbers for illustration only.)

Anyway, you already know the temperature currently ends up lower than you want with a cup of water added to a cold cup. So, logically, the next thing to try is to add a preliminary cup of water for the express purpose of pre-heating the cup, toss it out, and add a fresh cup for steeping. The steep water will lose less heat during steeping because the cup won't be so eager to draw it away. Once the cup has been pre-heated, the steep water in a more massive cup or mug may maintain heat better than that in a pre-heated thin cup, which would be a more effective radiator to the surrounding air.

It remains to be seen whether that will be enough of an improvement to serve your brewing goals. I also tend to put a saucer over the cup while steeping to delay heat loss, to retain heat for the steep.. If you're still a few degrees shy of what you want after trying all that, you can try pre-heating a small vacuum bottle as your steep vessel. That should get you there if the simpler tactics do not!

Hope this helps some ... Good luck, good leaf.

Reply to
Clark Kent

In Britain 'tis learned at mother's knee that an essential prerequisite to making good tea is to warm the tea pot first. Black tea of course. The pot is also considered when measuring in the tea "one spoon for each person and one for the pot".

Nigel at Teacraft

Reply to
Nigel at Teacraft

While I was learning to brew chinese teas in Kuala Lumpur, the most common method of judging water temperature taught to me was touch. Heated water was poured from the kettle into a fair cup and repeated tapping of the fair cup with your fingertips allows you to judge the temperature. This does take quite a bit of practice, but it is possible to get very accurate.

All brewing vessels are preheated with boiling water.

Reply to
Cameron Lewis

That last bit is probably very good advice for those concerned about significant heat-loss while pouring the water into a teapot. Warming the brewing vessel(s) with hot water before brewing the tea would more than likely make a big difference.

N.

Reply to
WNW

Cameron snipped-for-privacy@posting.google.com9/17/03

22: snipped-for-privacy@mailandnews.com

Yes, quite quite right. I often add a drop or two of water for the initial aroma fix. Also, using a cup with easily grasped and removable inner infuser, I sometimes grab out the infuser for a sniff. Any port in a storm. Your point about aroma is well taken.

snip

Michael

Reply to
Michael Plant

Smelling dry Japanese tea in a warmed pot is indeed a great pleasure.

I had been out of Gyokuro for a month or so, and with the August heat, I really didn't feel compelled to get some right away. Besides, I was making due with some Ti Kwan Yin and the occasional Darjeeling. Now, though, I have some again. That first taste after going without was almost narcotic in it's effect. I actually had to close my eyes after swallowing, my head lowered. Perhaps now you can understand why I feel little compelled to try out other teas.

--crymad

Reply to
crymad

Some of the finer green teas have the same effect on me, especially when I taste them after not having had any for a while -- they make me sit in appreciative silence, sometimes with eyes closed, simply enjoying their goodness.

N.

Reply to
WNW

Reply to
juanon

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.

Reply to
ChipsChap

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