How much heat can a tetsubin take?

miig
Posts: 33
Joined: Mon Jan 15, 2018 3:12 pm
Location: Germany

Wed Nov 10, 2021 3:57 pm

Hi guys,

I am on the process of rediscovering Tetsubin and thus am coming back to an old worry of mine. Thing is, I got a tetsubin that is said to be 50-60 years old. It is very beautiful, but with almost 3l of volume overly bulky and massive - not very practical for tetsubin standards.

The hotplate I use is a rommelsbacher 15cm 1000 watt hotplate. If I use level 2/3, it is fine, but it takes more than 30 minutes to heat 700ml of water. If I use level 3/3, it gives a lot of cracking noises that are very worrying. I also tried starting off with a lower setting and gradually increasing power, same effect. As soon as I go beyond 66% power, mr. tetsu makes very unhealthy noises.

Due to several reasons, I have ordered a new kunzan one from artistic nippon. It should fit better - 1,6l of volume, and 13.2cm bottom plate for improved heat transfer. So now I wonder how much power I should be giving it - do you think it will take the full 1000w without damage in the long run? Also, do you consider it wise to start at a lower setting, or is it too much effort?

(I know not to put cold water in a hot tetsu etc.)
DailyTX
Posts: 882
Joined: Wed Jul 03, 2019 4:43 pm
Location: United States

Wed Nov 10, 2021 4:19 pm

miig wrote:
Wed Nov 10, 2021 3:57 pm
Hi guys,

I am on the process of rediscovering Tetsubin and thus am coming back to an old worry of mine. Thing is, I got a tetsubin that is said to be 50-60 years old. It is very beautiful, but with almost 3l of volume overly bulky and massive - not very practical for tetsubin standards.

The hotplate I use is a rommelsbacher 15cm 1000 watt hotplate. If I use level 2/3, it is fine, but it takes more than 30 minutes to heat 700ml of water. If I use level 3/3, it gives a lot of cracking noises that are very worrying. I also tried starting off with a lower setting and gradually increasing power, same effect. As soon as I go beyond 66% power, mr. tetsu makes very unhealthy noises.

Due to several reasons, I have ordered a new kunzan one from artistic nippon. It should fit better - 1,6l of volume, and 13.2cm bottom plate for improved heat transfer. So now I wonder how much power I should be giving it - do you think it will take the full 1000w without damage in the long run? Also, do you consider it wise to start at a lower setting, or is it too much effort?

(I know not to put cold water in a hot tetsu etc.)
@miig

I also use a cast iron hotplate (1500 watt full power) as a heating source for my tetsubin. I treat my tetsubin like a cast iron pan...as long as it has water, I think it should be fine. If don't want to wait for the hotplate to heat the water to boiling point, you can use an electric kettle to boil the water and transfer the hot water into the tetsubin, it should be faster. The cracking sound maybe coming from the hotplate, just a guess. Enjoy!
miig
Posts: 33
Joined: Mon Jan 15, 2018 3:12 pm
Location: Germany

Wed Nov 10, 2021 4:44 pm

Hi,
thanks for your reply. So you go from 0-max with your tetsu always? Which model of hotplate do you have, I wonder?
DailyTX wrote:
Wed Nov 10, 2021 4:19 pm
If don't want to wait for the hotplate to heat the water to boiling point, you can use an electric kettle to boil the water and transfer the hot water into the tetsubin, it should be faster.
Pre-heating the water and then pouring it into the tetsu feels wrong :twisted: I can't do that. But yes, it would work :)
DailyTX wrote:
Wed Nov 10, 2021 4:19 pm
The cracking sound maybe coming from the hotplate, just a guess. Enjoy!
I suspected that, too. But it doesn't.
a) No cracking if the stove is set to 2/3 or lower.
b) I use it often with a Lin's clay kettle and a Stainless Steel kettle. I love the latter - it's completely worry-free. Bump it against stuff, leave water in it all day, pour water in the hot thing - it will take all that for decades to come. But I digress - no cracking with the other pots, regardless of the power settings. Happens only with the old tetsu and full power.

Image

Here it is, by the way.
DailyTX
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Wed Nov 10, 2021 4:49 pm

miig wrote:
Wed Nov 10, 2021 4:44 pm
Hi,
thanks for your reply. So you go from 0-max with your tetsu always? Which model of hotplate do you have, I wonder?
@miig

This is the one I am using:
miig
Posts: 33
Joined: Mon Jan 15, 2018 3:12 pm
Location: Germany

Wed Nov 10, 2021 5:12 pm

Hi,

I can't see it :)
DailyTX
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Wed Nov 10, 2021 5:44 pm

miig wrote:
Wed Nov 10, 2021 5:12 pm
Hi,

I can't see it :)
Here: Cusimax Hot Plate Electric Burner Single Burner Cast Iron hot plates for cooking Portable Burner 1500W with Adjustable Temperature Control Stainless Steel Non-Slip Rubber Feet, Upgraded Version
miig
Posts: 33
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Location: Germany

Wed Nov 10, 2021 5:56 pm

Got it, thanks. Looks nice.
.m.
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Location: Prague

Wed Nov 10, 2021 8:30 pm

That's a nice tetsubin. Although 3l sounds a little bit heavy. :)

The cracking noise might indicate some tension in the material, which is a bit worrying. Could it be because you fill it less than 1/4? In theory the water allows to take the heat from the base and redistribute it more evenly, and in particular it prevents overheating of the base, but if too little water is used then the top of the kettle may still be significantly cooler than the bottom resulting in tension in the material...
I use my tetsubin on infrared kitchen stove on a maximum power, not sure how much it is, but it heats 700ml in about 10min, i'd have time it. I usually fill between 1/2 and 2/3 of volume.
miig
Posts: 33
Joined: Mon Jan 15, 2018 3:12 pm
Location: Germany

Thu Nov 11, 2021 2:32 am

.m. wrote:
Wed Nov 10, 2021 8:30 pm
That's a nice tetsubin. Although 3l sounds a little bit heavy. :)

Thanks m :) Yeah, it is gorgeous, but way too big. That makes it very difficult to handle, but also it absorbs great amounts of heat and thus it takes very long for water to boil.
.m. wrote:
Wed Nov 10, 2021 8:30 pm
The cracking noise might indicate some tension in the material, which is a bit worrying. Could it be because you fill it less than 1/4?
Agreed. I had it in for repairs, which was quite a desaster - most of the bottom exploded when they tried to weld it, and now it has been replaced in a way that I'm not super thrilled about.

Before:

Image
Image

After :?

Image
Image


I dont really blame the company, they didn't know how to work with this and did their best. Anyhow, they said it was a nightmare to work with because the iron is not only very brittle but even flaky and comes off in distinct layers, like puff pastry. So I don't dare use it at this point. Also I don't know the material they used. A sand-iron+urushi-plug would have probably solved the problem.


But this is probably why its crackling - the stuff is moving internally, way more than it should.

That's why I got a new one now, Kunzan via Artistic Nippon. That one has the right size and is new sturdy. Now i wonder if I can give this one full heat or not - i'd like to have it last a little while, especially since I haven't found anyone in Europe who could fix a leaky Tetsubin bottom... tried to find someone, but the welding company is specialized in other stuff...
DailyTX
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Thu Nov 11, 2021 10:08 am

@miig
Thanks for sharing your repair experience. One of my tetsubins could use some repair but it’s old enough to be a display piece. The inside does look like those flaky pastry as you mentioned but it doesn’t leak yet. Looking at your photos helped made up my mind to leave it as it is.
miig
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Location: Germany

Thu Nov 11, 2021 12:38 pm

Yes @DailyTX, I'd only give such a Tetsubin to someone now who definitely has worked with them. An experienced Tetsu mechanic will easily be able to put in a plug without altering the kettle's appearance. But when I did that research, I only found such people in Japan, which adds significant cost.
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Youzi
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Sat Nov 13, 2021 6:17 am

The heat problems are due to the urushi plug, which could melt or have a crack around it. Only a concern with more expensive tetsubins.

Cheaper mass made ones like Oigen and Iwachu, the not hand made ones, are fine to go with 100% power.
miig
Posts: 33
Joined: Mon Jan 15, 2018 3:12 pm
Location: Germany

Sat Nov 13, 2021 11:31 am

Thank you @Youzi for your input. Yes, I heard the same thing. The Tetsubin I ordered is from Kunzan, using Urushi plugs. So I wonder how much heat I can apply to this without the plugs taking damage on the long run.
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Youzi
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Sat Nov 13, 2021 2:52 pm

miig wrote:
Sat Nov 13, 2021 11:31 am
Thank you Youzi for your input. Yes, I heard the same thing. The Tetsubin I ordered is from Kunzan, using Urushi plugs. So I wonder how much heat I can apply to this without the plugs taking damage on the long run.
With those I'd go with as gently as possible, for your self to wait 10s of minutes to reach boiling. :D
miig
Posts: 33
Joined: Mon Jan 15, 2018 3:12 pm
Location: Germany

Sat Nov 13, 2021 4:53 pm

Thanks @Youzi. I will try some things - with the big Tetsubin, heating around 750ml takes up to 35 minutes - too long for some uses, especially since I heat water 3-4 times for a longer session. With the clay kettle, it's 15 minutes, with the stainless steel kettle that has a sandwich bottom, less than 10. I'd hope to achieve something like the 15minutes of the clay kettle...

If other Tetsubin owners here want to chime in, I'd be happy to see some experiences on how much power you give your tetsubin.
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