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Mar 2nd, '13, 22:48
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Temperature guessing with glass kettle?

by Joel Byron » Mar 2nd, '13, 22:48

I have a Yama glass kettle. I know you can estimate water temp by the size of the bubbles, but it seems that this kettle doesn't work that way. There are really no bubbles until the "fish eye" or "streaming pearl" stage of boiling. I'm using it on an electric stove with the wire "w" that comes with the kettle on the element. I do not live at high altitude.

It's not really a big deal, I can put a thermometer in the spout if I want to brew at a lower temp. Just wondering if anyone else has had the same experience with glass kettles. Although, I did get the kettle so I could estimate water temp without the thermometer.... :?

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Mar 2nd, '13, 23:03
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Re: Temperature guessing with glass kettle?

by the_economist » Mar 2nd, '13, 23:03

Plop some charcoal pieces into the kettle so that bubbles can form more easily.

Mar 3rd, '13, 10:01
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Re: Temperature guessing with glass kettle?

by Namnai » Mar 3rd, '13, 10:01

Bubbles require nucleation sites to form more easily. Nucleation occurs with more difficulty on surfaces that are very uniform like modern day glassware. Same reason why when you heat water in the microwave and then disturb it, it bubbles over. You nudged it ever so slightly to cause the bubbles to form and expand at a very rapid rate and hence the liquid bubbles over.

Skewers or other imperfect surfaces - like charcoal suggested- placed in the kettle/mug would remedy this and allow the bubble nucleation to occur more easily. Also avoiding the rapid bubbling over when you try to move the mug/container

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Mar 3rd, '13, 11:19
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Re: Temperature guessing with glass kettle?

by Teaism » Mar 3rd, '13, 11:19

Joel Byron wrote:I have a Yama glass kettle. I know you can estimate water temp by the size of the bubbles, but it seems that this kettle doesn't work that way. There are really no bubbles until the "fish eye" or "streaming pearl" stage of boiling. I'm using it on an electric stove with the wire "w" that comes with the kettle on the element. I do not live at high altitude.

It's not really a big deal, I can put a thermometer in the spout if I want to brew at a lower temp. Just wondering if anyone else has had the same experience with glass kettles. Although, I did get the kettle so I could estimate water temp without the thermometer.... :?


Joel,
It great that you are sensitive and observant. Yes you can guess quite accurately tell the temperature of the water by looking at the bubble. One of the basic skill of tea brewing is temperature control and this is one of the way to gauge it.

Another way is when you do not have glass kettle and cannot see the bubbles. You can guess the temperature by feeling the vibration of the kettle handle. Takes a lot of practice and feel on this but if you do it long enough, you can gauge it quite accurately.

You can buy a infrared thermometer to check the actual temp and calibrate with your sensing experience.

Give it a try and make it a habit. It is one of my habit now. :D

Cheers!

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Mar 3rd, '13, 11:30
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Re: Temperature guessing with glass kettle?

by Joel Byron » Mar 3rd, '13, 11:30

Thanks, that makes sense. Where is a good source for bamboo charcoal?

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Mar 3rd, '13, 11:51
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Re: Temperature guessing with glass kettle?

by wyardley » Mar 3rd, '13, 11:51

The charcoal will also help prevent superboiling. It will make a little bit of noise, though. Do you have a Japanese 99 cent store near you? Otherwise, you may need to find the charcoal online.

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