Yixing teapot - maintain temperature with surrounding water?

[Mark-S]

Hi,

Hopefully this is the right category for this question.

When I prepare tea in Yixing teapots I always use a bowl for the wastewater. However, I have seen that many people just pour it all over the teapot so that the teapot is completely surrounded by water/tea. How do they maintain the temperature this way? The surrounding water/tea cools down very quickly especially with very small pots.

[Bok]

I’ve been mystified by this as well, common logic has it the surrounding water will cool down the pot.

My explanation has a few points:

- people are lazy, can’t be bothered to control the pour and stay relatively dry.

- regions were gong fu method is used are very hot and humid so it won’t matter that much: Guangdong is very hot even at night and people brew outside. So westerners are just “aping” them without putting it into relationship to their own environment.

- some people just like to mess around with water

I do prefer a semi-dry style with a low bowl, if it’s too much water I empty in the waste water jar. Some old pots with high lid flanges are impossible to fill and close without water overflowing.

[Rickpatbrown]

I always pour my rinses on my pot to try to develope a patina.

It seems to reason that waste water is cooler than the pot, so it would indeed cool it, but I dont see that being a big deal for the first steep.

What I've witnessed on subsequent steeps, is people pouring water from the kettle over the pot. In this case, that water is very hot and may help elevate the outer clay temperature slightly.

In any case, I'm not sure how these minor changes in temperature would affect major differences in extraction, but maybe I'm not as skilled at sensing those differences.

[Mark-S]

I think that's a good explanation, thanks, @Bok

but I dont see that being a big deal for the first steep.

And after the first steep you empty the water in a wastewater bowl/jar? I am asking because I have seen people nearly drowning the teapot in wastewater during the whole session and this definitely cools down the pot a lot. If it's only for the first steep then it's not a big problem in my opinion.

[Bok]

@Mark-S mostly foreigners? Some things are just cultural miss-appropriations/understandings like pots must be drowned and Puerh must taste like dirt

[Hmm]

I don't get this either.

Won't the water cause more added mass, therefore allow easier transference of heat to warm up the cooling water mass?

If you're constantly pouring out the cooling waste water, and then adding in fresh boiling water every steep, then I can see how that would help maintain temperature a bit longer. Otherwise you're just cooling the pot faster than if you were just to have air surrounding it.

[Mark-S]

@Bok

Yeah, mostly foreigners

@Hmm

That's exactly what I thought. So I'll just continue with my style then. I don't pour water/tea over my big teapots and with the small pots I'll pour out the old water/tea after each steep.

Thanks for the help

[mbanu]

So there is tea rinsewater and fresh boiling water. These are used at different times.

When you brew, you want the teapot to be a certain temperature, but when you are not brewing, you want it to cool as quickly as possible to keep the leaves from stewing.

So the cycle would be something like:

1. Preheat empty pot with boiling water.
2. Rinse the tea, saving the tea rinsewater (one reason for the design of those tea boats with a platform for the pot is because it allows the rinsewater to spread and cool more quickly, I think).
3. Make the first round.
4. Pour the cooler tea rinsewater on the outside of the pot to help it to chill, then remove the lid to help evaporative cooling.

OK, now you have a pot that is not so warm, but you want to make a second steep.

5. You put the lid back on the partially used leaves and then pour boiling water on the outside. While there will be a bit of evaporative cooling at the end, the pot is small enough that you can raise the temperature more with the boiling water than will be lost through the cooling. You can also wipe off the pot with a dry pot brush or teacloth.
6. Now you can pour boiling water in for the next round, and the pot will already be warm, as though you had preheated it the first way.
7.You can repeat the cooling step with that first tea rinsewater again and again, since it is now just a tool for drawing temperature from the pot while maybe transferring some tea seasoning to the exterior.

[Bok]

@mbanu that is the first time I hear this theory, where did you get it from?

The thing people to do to keep it from stewing the leaves in between brews is simply leaving the lid next to it, that is by far enough. A cooled down pot is much more detrimental to consequent brews...

[faj]

When you brew, you want the teapot to be a certain temperature, but when you are not brewing, you want it to cool as quickly as possible to keep the leaves from stewing.

I would think the best way to "cook" leaves is putting them in hot water, as water contains much more heat by unit of volume and transfers it more quickly than air. When you pour the tea out, the most harm you can do to the leaves is probably already done. Now, I understand you might want to cool the leaves after that to prevent further damage.

Intuitively, I would say that, by an order of magnitude at least, evaporative cooling of the leaves is going to be a much more powerful driver for cooling them than reducing the temperature of the pot (which reduces heat transfer by contact, convection and radiation). That will be especially true for teas that have leaves that will allow air to circulate better between the leaves, which, I would say, happen to be the kind of teas that are associated with hot water infusion.

In other words, if you want your hot leaves to cool fast, you might be better lifting the lid quickly to let cool air in rather than leaving it on and pouring cool liquid on top of the pot. This is not something I have tested, but it seems to me there is a good case to be made that just removing the lid is not only "good enough", but might conceivably turn out to be better than the more complicated alternative.

If I were compelled to come up with an "extreme cooling" method, it would probably involve blowing air inside the pot to increase evaporative cooling rather than trying to cool the teapot.

[mbanu]

@Bok, a bit of reverse-engineering, I guess.

We know the two goals, which are to keep the pot warm when it is brewing tea, and to keep the leaves cool when it is not, and we have the tools. What actually started me on it was re-reading John Blofeld's old book.

When he described his gongfu set back in the 1980s, it had not just a tea tray for catching water, but also a tea-boat and a cup-plate; now why would someone need so many ways to catch rinsewater? And why is his tea boat deep while his cup-plate is shallow? Wouldn't it just be easier to have two cup-plates? Or one big cup-plate? Or to get rid of the boat and the plate and just do everything on the tea tray which catches all the water anyway? This got me to thinking about how tea rinsewater is used.

One thing that clicked was when Blofeld mentioned that his tea-boat was deep because he was taught to pour boiling water over the pot until it was almost half-submerged. Now why would someone do that? Well, the parts of the pot that are underwater are not suffering from evaporative cooling directly, so maybe a deep tea boat would do a better job at helping to warm the pot than a shallow cup-plate or a tea tray.

When Blofeld was making tea, he was taught that the tea rinsewater goes straight into the tea tray; so why then would some people pour it over the exterior of the pot, especially after having been poured into the cups, cooling it even further? There are the explanations about patina, yes, but the tea rinsewater will be cool, which is not helpful -- unless you pour it on the pot when it no longer needs to be hot, such as between steepings.

[mbanu]

Intuitively, I would say that, by an order of magnitude at least, evaporative cooling of the leaves is going to be a much more powerful driver for cooling them than reducing the temperature of the pot (which reduces heat transfer by contact, convection and radiation). That will be especially true for teas that have leaves that will allow air to circulate better between the leaves, which, I would say, happen to be the kind of teas that are associated with hot water infusion.

In other words, if you want your hot leaves to cool fast, you might be better lifting the lid quickly to let cool air in rather than leaving it on and pouring cool liquid on top of the pot. This is not something I have tested, but it seems to me there is a good case to be made that just removing the lid is not only "good enough", but might conceivably turn out to be better than the more complicated alternative.

This would be a fun test! If I understand correctly, we would time how long it takes to pour the tea rinsewater over the pot before taking off the lid, and then compare it with if we had just left the lid off for that additional amount of time?

[Youzi]

I have a simple practice that I picked up myself during my sessions.
Basically I preheat the pot.
Then Rinse the tea. (pour the rinse into the cup, so it picks up some aroma, stays warm)
Do the first infusion.
Pour out into the cup. (rinse is poured into the waste jar)

Then basically blow out the hot steam air inside the pot. It's enough to quickly drop the temperature around the leaves, but still keep the pot fairly warm and the laves, so they don't cool down too much. After this, I put back the lid, to preserve the temperature. I found teas to last more infusions this way, and produce more consistent results.

No need to play with water, and 100% dry brew compatible.

[faj]

This would be a fun test! If I understand correctly, we would time how long it takes to pour the tea rinsewater over the pot before taking off the lid, and then compare it with if we had just left the lid off for that additional amount of time?

I happened to have leaves in a teapot on the counter waiting for their next infusion, so I made a quick test.

I preheated the pot by making an infusion, which I poured out. I made another infusion right after that. Before pouring the water out, I measured the water temperature (about 90C) with a contact thermometer. I then poured the tea out and switched to an infrared thermometer before opening the lid, which read a bit below 85C right after opening. Within the first 5-10 seconds, it dropped to below 75C, then cooling more gradually to below 70C. I do not know how low the temperature must drop to avoid "cooking the leaves", but opening the lid allows a significant and quick drop within a short amount of time.

At the beginning, the leaves are hotter than the pot, but after 15-20 seconds they are actually cooler than the pot, and at that point I guess the temperature of the vessel contributes quite a bit to the much slower observed cooling through conduction, radiation and convection.

This is not a teapot that lends itself to pouring water on top, so I did not try the other method.

[faj]

Then basically blow out the hot steam air inside the pot. It's enough to quickly drop the temperature around the leaves, but still keep the pot fairly warm and the laves, so they don't cool down too much.

This makes a lot of sense. Basically, you try cooling the leaves just enough so that they are protected, while retaining the most heat overall to optimize water temperature of the next infusion. Maybe cooling a few degrees is enough to protect the leaves, and I will take the results you observe as hinting that it might well be.