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Mar 17th, '09, 16:44
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by hpulley » Mar 17th, '09, 16:44

All I know is my induction stove says not to use cast iron on it so I'm not going to risk voiding the warranty with a frying pan, tetsubin or anything.

As for rust in the tetsubin, "seasoned" and used properly it should NOT rust internally much if at all. I know most old ones you see on eBay are in terrible, terrible shape but with the right water and correct use it isn't a problem.

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Mar 17th, '09, 16:50
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by MarshalN » Mar 17th, '09, 16:50

Oh in general they don't rust that much, but they do eventually rust -- iron is iron and it will react with water, especially if you use it a lot.

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by MarshalN » Mar 17th, '09, 16:50

And I think guessing they ask you not to use cast iron mostly because induction plates will get scratched up by the rough cast iron surface

Mar 17th, '09, 18:06
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by Intuit » Mar 17th, '09, 18:06

Gas burner forms carbonic acid:

CH4 + O2 ---> CO2 + H20 ---> carbonic acid (acidic attack on iron when hot, causing rust)

Maybe labile iron in certain tetsubins (ie., not treated under reductive oven conditions to prevent this) can chemically 'attack' partially oxidized tea oil components in aged and fermented teas, making them slightly bitter or perhaps it attacks secondary reaction components that contribute to aroma?

:unsure:

Induction burners and cast iron: would have to be the rate of heating, causing uneven expansion between cast iron and typical ceramic lining??

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Mar 17th, '09, 18:50
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by chamekke » Mar 17th, '09, 18:50

Intuit wrote:Induction burners and cast iron: would have to be the rate of heating, causing uneven expansion between cast iron and typical ceramic lining??
But a lined cast-iron tetsubin shouldn't be placed on any type of heat source.

I have been assuming that this discussion is about unlined tetsubin ("teakettle") rather than the lined variety ("teapot"). So my question is, why would there be a problem with putting an unlined, pure cast-iron tetsubin on an induction burner? The heating would be even, rather than otherwise...
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Mar 17th, '09, 19:39
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by Intuit » Mar 17th, '09, 19:39

>But a lined cast-iron tetsubin shouldn't be placed on any type of heat source.

Not true. I found more expensive tetsubin that were lined and could be used on a stove to heat water (not intended to be used as a teapot).

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Mar 17th, '09, 20:05
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by chamekke » Mar 17th, '09, 20:05

{cautiously} That seems to suggest that a flat-bottomed tetsubin should be OK with an induction plate...
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Mar 17th, '09, 20:07
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by MarshalN » Mar 17th, '09, 20:07

Tom, rather than worrying about induction plates, I'd suggest just getting a regular heating plate. Yes, it's more dangerous as it will cook everything, not just iron/steel, but it does work quite well and that's what I normally use these days. I don't see why cast iron should not work. They're usually thick enough, I'd imagine.

It has been my experience trying to use tetsubin water to brew various types of tea that, in general, it softens the teas in question, and personally I find it enhances the flavour/mouthfeel of the tea.

Mar 17th, '09, 21:09
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(I) Second the motion.

by Intuit » Mar 17th, '09, 21:09

Agree with Marshall. Get a regular variable power hot plate. They're cheaper and they will work just as well as the induction coil, plus you won't have the worry of whether or not cast iron is in fact safe to use on an induction heater.

A lined tetsubin negates the original purpose (Japanese and Chinese) of using cast iron to improve the taste of super soft water. Some teas (many black teas, for instance) taste flat when prepared in very soft water. The oldest Glaswegian tea houses had tea blends prepared that tasted good when prepared using the very clean/soft loch water that has been the primary public water supply of Glasgow Scotland for a long, long time.

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Mar 17th, '09, 23:33
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by chingwa » Mar 17th, '09, 23:33

Yes the electric cooktops are cheaper, and they work well, but I wouldn't say they work AS well. Induction will heat the tetsubin directly (rather than having to heat an electric element first then transfer that heat to the kettle on contact.) This reduces wasted energy and drastically cuts the time it takes to bring water to a boil.

I've had no problems heating my tetsubin with induction, I've been doing it for about 3 months now.

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Mar 18th, '09, 02:24
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by Oni » Mar 18th, '09, 02:24

Thanks for the info, I will buy a tetsubin on my birthday, that is in 1st of june, and I will use it on an electric stove, but when you use such a stove, the hot plate will not cool down when you shut it off, so I think you bring the water to fish eye, use the required amount and than remove from the stove, to a stand, till I am ready to start the next infusion, than I can put it back and heat it to the right temperature, and I will probably need to remove the lid to see the bubbles.

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Mar 18th, '09, 08:21
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by hpulley » Mar 18th, '09, 08:21

For most tetsubin which lack a hole in the lid it is in fact best practice and traditional to have the lid open while heating it. Once at the right temperature you reduce or turn off the heat, close the lid and dispense the water. When tea is finished, you open the lid again to signify that it is over.

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Mar 18th, '09, 13:37
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by JoeCha » Mar 18th, '09, 13:37

I can second hpulley on leaving the lid off if there is no whole to vent.

If I don't, I end up with a boiling water fountain arching across my kitchen.

The pressure pushes the water out of the spout.

--J

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Mar 20th, '09, 14:45
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by wyardley » Mar 20th, '09, 14:45

BTW, for anyone who's interested: http://half-dipper.blogspot.com/2009/03 ... g-101.html
Hopefully will dispel some of the myths / misinformation around induction... I'm personally neutral on the issue, and I am not using a metal kettle right now anyway.

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