Jan 19th 16 4:20 pm
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Tall glass & hotplate

by Gianfra » Jan 19th 16 4:20 pm

Hello,
I'd like to ask a couple of questions, maybe someone can help me. First one probably is a stupid one for most of you. I read that you can use a tall glass for brewing some green teas; is this glass heat resistant? I ask that because, looking around, I cannot find an heat resistant glass like that, just the normal one for cocktails etc. . Or maybe is not necessary because you usually don't brew green tea with boiling water?
The second one is about an infrared hotplate. I just bought one from aliexpress (didn't get it yet), the description says that when you turn it on the original power is 600W, than you can adjust it up to 1500w. Now , I use a tetsubin and I would like to know if starting from 600w can be dangerous. For now I use my gas stove starting at a VERY low flame, however the gas make the tetsubin rust (outside) so that's why I would like to try an electric stove. Anybody has experience with an infrared mini stove/tetsubin? I don't want to damage it, better rusty and alive!
Thank you

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Jan 19th 16 4:37 pm
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Re: Tall glass & hotplate

by Fuut » Jan 19th 16 4:37 pm

1. Most glass wares (unless you get the standard IKEA cups) aren't made to use with very hot liquids. Or heating them in say a microwave. Most glass made chawan for instance are used for cold tea.
2. Heat element / plate, I'm not experienced with using these with a tetsubin or chagama, but i don't think it would cause harm.
3. Gas fire is not good for caste kettle and the like, because there is water, (i can't recall the right word) released in the vapors and that causes the rust. An electric stove see 2, i can't imagine the heat damaging it.

Though best would be just to use the charcoal:)

Don't take these as fact, someone more experienced and knowledgeable will come along.

Jan 20th 16 9:48 pm
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Re: Tall glass & hotplate

by Gianfra » Jan 20th 16 9:48 pm

Thank you Fuut,
I'd like to brew some Taiping Houkui in a glass, the leaves are too long for my little teapot. I know someone use tall glasses, so I wonder if a regular glass can resist 80° or so.
I live in a flat, I have no possibility to use charcoal; I don't have even a balcony.
I asked about the danger of using an hotplate because I read on Hojo website that you have to be very careful using an induction plate and also you have to start heating with low temperature. Infrared stove is different but I prefere to be cautious.
Thanks

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Jan 20th 16 11:39 pm
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Re: Tall glass & hotplate

by Frisbeehead » Jan 20th 16 11:39 pm

I use a regular tall glass for Longjing, and I haven't had problems. I pour boiling water into it. I'm not sure if I'm pushing its limits or anything, but it hasn't broken on me. It is also not very thin glass, it is I would say medium thickness. Like a typical tall plain glass you'd find at any kitchenware/houseware type store.

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Jan 21st 16 3:47 pm
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Re: Tall glass & hotplate

by hopeofdawn » Jan 21st 16 3:47 pm

Generally most glasses are safe to pour hot water into, but I wouldn't boil anything directly in a glass on a hotplate or a stove unless you get something that's designed for that (Pyrex, for example).

Jan 21st 16 6:53 pm
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Re: Tall glass & hotplate

by Gianfra » Jan 21st 16 6:53 pm

Thank you very much! I'm going to try then..

Jan 21st 16 8:18 pm
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Re: Tall glass & hotplate

by .m. » Jan 21st 16 8:18 pm

- mason jar (or any kind of jar) is your friend,
- thermal shock isn't your friend.
- glasses with a thick bottom and thin walls are usually prone to cracking.
- gentle preheating is always a good idea.
- cast iron has surprisingly small heat conductivity, so it is safer to start slowly and increase the heat when it gets warm, but i understand that you've been already doing that. for example putting cast iron pan straight on high heat may over an extended period of time warp it, but i've never heard of cracking. i'm using a ceramic kettle on an old cast iron hotplate which has the advantage/disadvantage to start really slow, it is a different situation...

Jan 22nd 16 10:05 pm
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Re: Tall glass & hotplate

by Gianfra » Jan 22nd 16 10:05 pm

Hi,
actually when I watch a video or pictures on the web brewing green tea with a glass it has usually a thick bottom; of course I don't know how thick are walls. Anyway breaking a glass isn't a big problem but a tetsubin is another story! For safety, now that is cold, I don't even put it on the weak flame but I hold it 30-40cm over the flame for one or two minutes until the tetsubin get a little warmer. Perhaps I exaggerate....

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Jan 23rd 16 4:41 pm
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Re: Tall glass & hotplate

by Evan Draper » Jan 23rd 16 4:41 pm

I spent a long time looking for a green tea glass just as you described. Tough to find one that is durable but also not too large. I just had a friend bring a couple from China. Since that may not be possible for everyone, looking for a "Collins glass" will point you to appropriate dimensions. (I drink more Collinses out of them these days anyway!) Lab glassware (flasks, graduated cylinders) are a quirky presentation but are designed to handle the heat. Preheating is your friend, and you probably don't want to use boiling water with Chinese greens anyway.

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Jan 23rd 16 4:53 pm
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Re: Tall glass & hotplate

by Evan Draper » Jan 23rd 16 4:53 pm

Gianfra wrote:I'd like to brew some Taiping Houkui in a glass, the leaves are too long for my little teapot.
Before I found an appropriate glass, I was brewing TPHK in a gaiwan. The first time I tried it was with a friend, and I offhandedly broke some of the leaves in half. The guy wound up outing my sloppy technique on the Internet.... :lol: You can simply let the leaves moisten gradually, and they will slide in like spaghetti--uneven extraction is not a big deal.

Jan 24th 16 10:07 pm
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Re: Tall glass & hotplate

by Gianfra » Jan 24th 16 10:07 pm

Thank you E.D.,
I didn't know about Collins glasses, first time I hear it but they looks what I was looking for.
I love tea and teawere as well (I'm sure like all the forum members), I'm not attracted to drink tea from a lab glass or a mason jar, sorry! A tall glass it's not that beauty but it's ok, it is decent! I'll try soon, thank you very much.

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Jan 25th 16 2:18 am
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Re: Tall glass & hotplate

by miig » Jan 25th 16 2:18 am

Hi there,
It will probably be for the best to heat the water in another source. There are glass kettles which don't cost a lot of money, and can be used on your stove and the infared plate, too.
But for longjing you'd want the water not to be too hot anyways, 80°C max I'd say.

I'm using a Tetsubin on a hotplate (not infrared, but a cast-iron plate, but close enough :) ). Maximum power of my plate is 1000W, I start with about 600W, wait until the kettle has warmed up a bit and then go to full power. This should not be a problem, most people don't even bother with that :)

Jan 25th 16 10:22 am
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Re: Tall glass & hotplate

by Gianfra » Jan 25th 16 10:22 am

Hi Miig,
just for couriosity, how long does it take for boiling, let's say half liter, with your tetsubin/iron cast hotplate?
Thank you

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Jan 26th 16 8:00 pm
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Re: Tall glass & hotplate

by miig » Jan 26th 16 8:00 pm

Hi, hmm my tetsubin is quite large, 2,6l filled to the rim, so I never use less than 0.75 litres or so... usually about a litre. That takes 20-30 mins, depending on how quickly I move to the highest setting.

I also have a Lin's clay kettle, which is smaller. In this one, I can heat up 500ml in about 15 minutes if I push it. Its funny, but the clay kettles from Lin's seem very resilient as far as strong heat is concerned. But hit the edge of the table with that thing even once :evil: :evil: :evil:

Anyways, I thought a bout it a little, and even though I'm not a tetsubin expert or anything, I think I wouldn't worry so much about shocking your tetsu with high heat (unless it has been in the freezer before 8) ) Many people use such kettles over charcoal fires, and there you go from 0 to 100 in a couple of seconds, without any problems. But thats just guessing.

What should be avoided though is to pour cold water into the tetsubin that is still hot, e.g. if you want to heat up more water, or heating up the kettle without water in it.. this will obviously kill it quickly.

Jan 27th 16 10:06 pm
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Re: Tall glass & hotplate

by Gianfra » Jan 27th 16 10:06 pm

Hi, thanks a lot for the informations, so I have an idea what to expect from my new hotplate. About heating too fast, I worried about because I read it on Hojo website. He was talking about induction hotplate, however he wrote that using too strong heat will stress the metal; the weakness of the Tetsu are the two holes at the bottom that are filled with a kind of resin/iron. He talk about leaking rather than cracking. I like very durable things, I'd like my tetsubin to last a few hndreds years...ahahahaha...
Thanks again!