Yixing

faj
Posts: 710
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Sat Jan 09, 2021 4:42 pm

polezaivsani wrote:
Sat Jan 09, 2021 3:18 pm
thanks a ton for speaking some thermo dynamic sense into my filled with trite analogies head. I appreciate it!
Bear in mind that my reasoning could be flawed, but it could also be true yet useless. If an experienced tea drinker (i.e. not me) has determined through dedicated testing that, to her palate, thick teapots are better with tea X because of heat retention, that drinker could be wrong about the "heat retention" part, but still be right about how to make good tea. A given technique will yield the same results whether or not our intellectual understanding of the phenomena involved is right or wrong.
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Bok
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Sat Jan 09, 2021 7:16 pm

faj wrote:
Sat Jan 09, 2021 1:33 pm
polezaivsani wrote:
Sat Jan 09, 2021 12:54 pm
faj, those shuipings seem to have walls on the thinner side, which might be not ideal with heat loving teas.
I have posted previously on why I think thick walls will probably mean a lower infusion temperature except in specific conditions.

viewtopic.php?p=19339#p19339

The gist is this :
  • A teapot, thick or thin, is not going to heat the boiling water you put in it. The best it can do is reduce heat losses.
  • A thick teapot will insulate a bit more than a thin one, but that is probably a weaker effect compared to other heat losses (wait time between infusion where evaporative cooling is at work, thermal inertia of the leaves and teapot). Insulation has negligible impact for shot steeps.
  • A thick teapot (all other things being equal) will suck up more heat from the water compared to a thin one if both start at the same temperature, unless the teapot is as hot as the water.
If my reasoning is right, heat loving teas require, first and foremost, that time between infusions be kept very short. Since that is not, for better or for worse, how I drink my tea, I think a thin teapot actually achieves higher infusion temperature in (my) real world conditions, especially when using pots that are rather small (higher surface-to-volume ratio) as that increases the impact of thermal inertia relative to that of insulation properties.
I fully agree with you on that one! Never understood how that concept came to be. A pot that reacts fast with heat is best in my view. If the session drags on, or condition in are cold, the thicker one will also start to cool from outside, much harder to maintain or heat up such a clay again in the middle of a session. So I want my clay to heat up fast in order to always get the temp my tea needs.

I find a thicker pot much harder to control, too slow to react and adapt. It’s for low maintenance teas...
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OCTO
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Sat Jan 09, 2021 9:50 pm

faj wrote:
Sat Jan 09, 2021 10:33 am
At this time, the only Yixing teapot I own is a small modern "zhuni" teapot from M&L, but at some point I would like to experiment a bit more with Yixing clay, especially for Liu Bao which I like a lot. I wonder if pots like these could, as claimed, be expected to be well made with decent clay, keeping in mind I approach this from a tea drinker's perspective, not as a collector.
@faj

LiuBao lovers musts have at least one DCQ pot in their lineup os teapots! It's a perfect match with LiuBao. A well seasoned retailer / vendor will be able to advise you which DCQ pot is best for LiuBao!...

Cheers!!
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OCTO
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Sat Jan 09, 2021 9:53 pm

DailyTX wrote:
Sat Jan 09, 2021 2:14 pm
faj
Another for your consideration is EOT 90s di cao qing. I think this was talked about in earlier post. Those pots were order to pair with liu bao tea for the south East Asian market. I have one that I have been using for mid aged Sheng. If they have other shapes, I am more than happy to collect another
https://essenceoftea.com/collections/yi ... ing-teapot
+1
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Tea Adventures
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Sun Jan 10, 2021 3:48 am

OCTO wrote:
Sat Jan 09, 2021 9:50 pm
faj wrote:
Sat Jan 09, 2021 10:33 am
At this time, the only Yixing teapot I own is a small modern "zhuni" teapot from M&L, but at some point I would like to experiment a bit more with Yixing clay, especially for Liu Bao which I like a lot. I wonder if pots like these could, as claimed, be expected to be well made with decent clay, keeping in mind I approach this from a tea drinker's perspective, not as a collector.
faj

LiuBao lovers musts have at least one DCQ pot in their lineup os teapots! It's a perfect match with LiuBao. A well seasoned retailer / vendor will be able to advise you which DCQ pot is best for LiuBao!...

Cheers!!
I have been using a duanni pot for Liu Bao because I thought Duanni was best for this type of tea. Guess I need to rethink my brewing strategy.
karma
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Sun Jan 10, 2021 3:53 am

Tea Adventures wrote:
Sun Jan 10, 2021 3:48 am
OCTO wrote:
Sat Jan 09, 2021 9:50 pm
faj wrote:
Sat Jan 09, 2021 10:33 am
At this time, the only Yixing teapot I own is a small modern "zhuni" teapot from M&L, but at some point I would like to experiment a bit more with Yixing clay, especially for Liu Bao which I like a lot. I wonder if pots like these could, as claimed, be expected to be well made with decent clay, keeping in mind I approach this from a tea drinker's perspective, not as a collector.
faj

LiuBao lovers musts have at least one DCQ pot in their lineup os teapots! It's a perfect match with LiuBao. A well seasoned retailer / vendor will be able to advise you which DCQ pot is best for LiuBao!...

Cheers!!
I have been using a duanni pot for Liu Bao because I thought Duanni was best for this type of tea. Guess I need to rethink my brewing strategy.
duanni is just fine, don't worry about it if you like it
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Tea Adventures
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Location: Belgium

Sun Jan 10, 2021 11:15 am

karma wrote:
Sun Jan 10, 2021 3:53 am
Tea Adventures wrote:
Sun Jan 10, 2021 3:48 am
OCTO wrote:
Sat Jan 09, 2021 9:50 pm


faj

LiuBao lovers musts have at least one DCQ pot in their lineup os teapots! It's a perfect match with LiuBao. A well seasoned retailer / vendor will be able to advise you which DCQ pot is best for LiuBao!...

Cheers!!
I have been using a duanni pot for Liu Bao because I thought Duanni was best for this type of tea. Guess I need to rethink my brewing strategy.
duanni is just fine, don't worry about it if you like it
Yes, it’s fine at the moment. However, I have never tried brewing Liu Bao in a DCQ teapot. Now I want to know the difference (if there is any). This means I have a good excuse for another pot...
McScooter
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Location: NYC/NJ, USA

Sun Jan 10, 2021 3:37 pm

faj wrote:
Sat Jan 09, 2021 10:33 am
The Essence of Tea has a couple of inexpensive shuiping half-handmade teapots on offer, which they claim have decent clay :

At this time, the only Yixing teapot I own is a small modern "zhuni" teapot from M&L, but at some point I would like to experiment a bit more with Yixing clay, especially for Liu Bao which I like a lot. I wonder if pots like these could, as claimed, be expected to be well made with decent clay, keeping in mind I approach this from a tea drinker's perspective, not as a collector.
I'm not planning to pair it with Liu Bao, but I'm going to pull the trigger on the shuiping hongni from EoT later today, and can pass along my notes thereafter. I'm planning to experiment with yancha and younger sheng. Given even some of the recent discussion re: authentication of 70s pots in this thread, I think I'll just go with something modern, even if it ends up falling into the "tuition" category over time. Besides, 60/70s stuff is expensive enough as it is, and I think I prefer to give this pot a go vs. something equivalent from the green label period, at least at present.
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OCTO
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Mon Jan 11, 2021 9:41 am

My view before bedtime!... Cheers folks!!

E636253E-2E75-4234-8E7A-CBEE2E48AE00.jpeg
E636253E-2E75-4234-8E7A-CBEE2E48AE00.jpeg (157.82 KiB) Viewed 3846 times

A reflective moment before we head towards another lockdown.
faj
Posts: 710
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Mon Jan 11, 2021 10:27 am

OCTO wrote:
Sat Jan 09, 2021 9:53 pm
DailyTX wrote:
Sat Jan 09, 2021 2:14 pm
Another for your consideration is EOT 90s di cao qing. I think this was talked about in earlier post. Those pots were order to pair with liu bao tea for the south East Asian market.
+1
They have this one too, a much lighter shade of di cao qing. Is color typically an indication of anything? This teapot is part of their "clearance" section, handmade, but claimed to be sold at a price lower than they normally would. If the higher price is related to the teapot being handmade (the others above are half-handmade), it might not be worth it to me, but if the clay is better, maybe it would.

https://essenceoftea.com/collections/yi ... ing-teapot
dcq_shuiping_2.png
dcq_shuiping_2.png (464.94 KiB) Viewed 3835 times
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wave_code
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Mon Jan 11, 2021 10:35 am

Bok wrote:
Sat Jan 09, 2021 7:16 pm
faj wrote:
Sat Jan 09, 2021 1:33 pm
polezaivsani wrote:
Sat Jan 09, 2021 12:54 pm
faj, those shuipings seem to have walls on the thinner side, which might be not ideal with heat loving teas.
I have posted previously on why I think thick walls will probably mean a lower infusion temperature except in specific conditions.

viewtopic.php?p=19339#p19339

The gist is this :
  • A teapot, thick or thin, is not going to heat the boiling water you put in it. The best it can do is reduce heat losses.
  • A thick teapot will insulate a bit more than a thin one, but that is probably a weaker effect compared to other heat losses (wait time between infusion where evaporative cooling is at work, thermal inertia of the leaves and teapot). Insulation has negligible impact for shot steeps.
  • A thick teapot (all other things being equal) will suck up more heat from the water compared to a thin one if both start at the same temperature, unless the teapot is as hot as the water.
If my reasoning is right, heat loving teas require, first and foremost, that time between infusions be kept very short. Since that is not, for better or for worse, how I drink my tea, I think a thin teapot actually achieves higher infusion temperature in (my) real world conditions, especially when using pots that are rather small (higher surface-to-volume ratio) as that increases the impact of thermal inertia relative to that of insulation properties.
I fully agree with you on that one! Never understood how that concept came to be. A pot that reacts fast with heat is best in my view. If the session drags on, or condition in are cold, the thicker one will also start to cool from outside, much harder to maintain or heat up such a clay again in the middle of a session. So I want my clay to heat up fast in order to always get the temp my tea needs.

I find a thicker pot much harder to control, too slow to react and adapt. It’s for low maintenance teas...
I'm sure some of this comes out of simple marketing combined with maybe a mis-interpretation of "heat retention". marketing in the sense that thick walls = good heat retention = most important thing because I said so and you don't know any better, sort of in the same way that showing pot can be flipped over without a lid coming off or tight lid fit now seems to indicate that a pot is good :roll: .

the other thing I wonder if it adds to this or in combination is that if a thick walled pot stays hot to the touch on the outside, because its drawing the heat out (someone correct my physics here please?), people interpret this as good heat retention because its hotter to the touch than their other pots, but that might not indicate the actual internal/water temp. I've been meaning to get a kitchen thermometer and do a test between 3 different clays in the same size volume over time, see which one actually maintains the actual water temp the best/longest, because theres also no reason to assume the curves of the cooling rates would be the same either, possibly making some clays better for different brewing styles.

I wonder if some of this also has to do with some clays that tend to have thicker walls holding heat better, not because of the thickness necessarily but because of the other characteristics (like clay density/porosity), and that the clay's characteristics require it to be thicker causing the assumption in people thick walls = heat retention? my experience is limited but I've found nixing and jianshui to have good heat retention for longer brews (from the outside touch at least, which could be inaccurate), but those pots tend to be thicker because the clays tend to be wheel thrown or crack easier, thus thicker walls, and that if thin walled jianshui pots were possible they might hold heat just as well.
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Youzi
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Mon Jan 11, 2021 11:47 am

wave_code wrote:
Mon Jan 11, 2021 10:35 am
Bok wrote:
Sat Jan 09, 2021 7:16 pm
faj wrote:
Sat Jan 09, 2021 1:33 pm


I have posted previously on why I think thick walls will probably mean a lower infusion temperature except in specific conditions.

viewtopic.php?p=19339#p19339

The gist is this :
  • A teapot, thick or thin, is not going to heat the boiling water you put in it. The best it can do is reduce heat losses.
  • A thick teapot will insulate a bit more than a thin one, but that is probably a weaker effect compared to other heat losses (wait time between infusion where evaporative cooling is at work, thermal inertia of the leaves and teapot). Insulation has negligible impact for shot steeps.
  • A thick teapot (all other things being equal) will suck up more heat from the water compared to a thin one if both start at the same temperature, unless the teapot is as hot as the water.
If my reasoning is right, heat loving teas require, first and foremost, that time between infusions be kept very short. Since that is not, for better or for worse, how I drink my tea, I think a thin teapot actually achieves higher infusion temperature in (my) real world conditions, especially when using pots that are rather small (higher surface-to-volume ratio) as that increases the impact of thermal inertia relative to that of insulation properties.
I fully agree with you on that one! Never understood how that concept came to be. A pot that reacts fast with heat is best in my view. If the session drags on, or condition in are cold, the thicker one will also start to cool from outside, much harder to maintain or heat up such a clay again in the middle of a session. So I want my clay to heat up fast in order to always get the temp my tea needs.

I find a thicker pot much harder to control, too slow to react and adapt. It’s for low maintenance teas...
I'm sure some of this comes out of simple marketing combined with maybe a mis-interpretation of "heat retention". marketing in the sense that thick walls = good heat retention = most important thing because I said so and you don't know any better, sort of in the same way that showing pot can be flipped over without a lid coming off or tight lid fit now seems to indicate that a pot is good :roll: .

the other thing I wonder if it adds to this or in combination is that if a thick walled pot stays hot to the touch on the outside, because its drawing the heat out (someone correct my physics here please?), people interpret this as good heat retention because its hotter to the touch than their other pots, but that might not indicate the actual internal/water temp. I've been meaning to get a kitchen thermometer and do a test between 3 different clays in the same size volume over time, see which one actually maintains the actual water temp the best/longest, because theres also no reason to assume the curves of the cooling rates would be the same either, possibly making some clays better for different brewing styles.

I wonder if some of this also has to do with some clays that tend to have thicker walls holding heat better, not because of the thickness necessarily but because of the other characteristics (like clay density/porosity), and that the clay's characteristics require it to be thicker causing the assumption in people thick walls = heat retention? my experience is limited but I've found nixing and jianshui to have good heat retention for longer brews (from the outside touch at least, which could be inaccurate), but those pots tend to be thicker because the clays tend to be wheel thrown or crack easier, thus thicker walls, and that if thin walled jianshui pots were possible they might hold heat just as well.
I think it's best to go back to the basics. What matters most when brewing tea, if the Leaf to Water Ratio is fixed?
The brewing time and your brewing Temperature.

The time is easily determinable. However your brewing temperature is not constant.

Firstly, when you add boiling water into your Gaiwan and leaves, the temperature of the Gaiwan + Leaves + Water has to come to an equilibrium.
Basically your water is heating up the the Gaiwan and the leaves, while the water cools down. This process isn't exactly linear at the higher temperatures (about 70-80+ degree range).

When an equilibrium is reached, let's say 80 degrees. Then starts the second phase of your brewing. The cool down phase. When the whole system (Gaiwan + Water + Leaves) starts to cool down, by surface convection of the Vessel. The rate of cooling is determined by the Heat Retention of the system.

Both phases are determined by one parameter: The specific heat of the Gaiwan/Pot + The Specific heat of the water. What Specific Heat tells you is basically how much energy you need to change the temperature of the System by 1 degree.

Water requires 4x more energy to change its temperature than Porcelain/Clay.

Based on my testing, unless you steep for really long times, over 6 minutes, heat retention doesn't really matter. Because it doesn't have enough time to take an effect, for 80% of a session, especially not at the beginning, which is the most important.

So really, what determines how "Strong" you can brew is basically how much porcelain/clay, you have to heat up, with your water. Because brewing at 80-75 degree for 5min vs brewing at 85-80 degree for 5 min, is a Huge difference in taste.
faj
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Mon Jan 11, 2021 12:03 pm

wave_code wrote:
Mon Jan 11, 2021 10:35 am
I wonder if some of this also has to do with some clays that tend to have thicker walls holding heat better, not because of the thickness necessarily but because of the other characteristics (like clay density/porosity), and that the clay's characteristics require it to be thicker causing the assumption in people thick walls = heat retention?
This is a valid question, and I have no answer.
wave_code wrote:
Mon Jan 11, 2021 10:35 am
my experience is limited but I've found nixing and jianshui to have good heat retention for longer brews (from the outside touch at least, which could be inaccurate)
The teapot being hot does not mean it is insulating well. It means it is losing heat. Think of a freezer : if you touch a freezer and find its wall is cold, will you conclude "this freezer has great cold retention"? Surely not. A perfectly insulating teapot would not feel hot on its outside, due to no heat leaking out. Of course, clay teapots are not perfect insulators, not by any means.

Heat may be lost due to contact (with air, with your hand) and radiation. Different clays could maybe feel warmer to the touch yet lose less heat by contact with air or ratiation. It is not easy to figure out intuitively. This being said, you would probably expect a better insulating teapot to feel not as hot as the beginning (better heat retention means less heat leaking out), but at some later time to feel warmer (because it has kept enough heat that it still has some to lose).
faj
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Mon Jan 11, 2021 12:18 pm

Youzi wrote:
Mon Jan 11, 2021 11:47 am
Both phases are determined by one parameter: The specific heat of the Gaiwan/Pot + The Specific heat of the water. What Specific Heat tells you is basically how much energy you need to change the temperature of the System by 1 degree.

Water requires 4x more energy to change its temperature than Porcelain/Clay.
Interesting. This means that if you put 100g of water at 100C in a 100g vessel preheated at 80C, the equilibrium temperature (excluding heat losses and the time it takes for that equilibrium to be reached) is about 96C (EDIT: previously incorrectly stated 85C, thanks to @Youzi for catching my silly mistake). That being said, insulation is important too : if the teapot were a perfect insulator (and sealed), water would remain at its initial temperature forever, no matter the respective specific heat of water and clay.
Youzi wrote:
Mon Jan 11, 2021 11:47 am
Based on my testing, unless you steep for really long times, over 6 minutes, heat retention doesn't really matter. Because it doesn't have enough time to take an effect, for 80% of a session, especially not at the beginning, which is the most important.
That makes sense, especially for very short brews.
Youzi wrote:
Mon Jan 11, 2021 11:47 am
So really, what determines how "Strong" you can brew is basically how much porcelain/clay, you have to heat up, with your water. Because brewing at 80-75 degree for 5min vs brewing at 85-80 degree for 5 min, is a Huge difference in taste.
It seems to me there is a way to cheat : if you are going to be brewing tea for several minutes and care for the temperature, you can perform a flash brew to preheat the teapot and leaves, pour that out, and add hot water again for the real infusion. The flash infusion is not going to cost much in terms of lost flavor (or else you would not need a long infusion), and you can still sip on it so there is no loss, really.
Last edited by faj on Mon Jan 11, 2021 12:44 pm, edited 1 time in total.
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Youzi
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Mon Jan 11, 2021 12:40 pm

@faj
Interesting. This means that if you put 100g of water at 100C in a 100g vessel preheated at 80C, the equilibrium temperature (excluding heat losses and the time it takes for that equilibrium to be reched) is about 85C.
No, the equilibrium temperature would be 96 degree. but at those temperatures it's not a linear thing anymore, so it'd probably be closer to 90.
It seems to me there is a way to cheat : if you are going to be brewing tea for several minutes and care for the temperature, you can perform a flash brew to preheat the teapot and leaves, pour that out, and add hot water again for the real infusion. The flash infusion is not going to cost much in terms of lost flavor (or else you would not need a long infusion), and you can still sip on it so there is no loss, really.
That's actually an awesome idea. Which further reinforces the need for lower mass teapots. As opposed to thicker heavier ones.
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