My (mostly pointless) heat retention experiment

[Benjamin]

Hey guys!

So I was chatting with a friend about the effects of clay on tea, and also the heat retentive properties of yixing and its contribution to the brew. I figured I'd line up a bunch of pots, rinse them all with hot water to pre-heat, dump, and refill to the brim. I didn't pour any water on the outside of the pots, but just let them all sit and waited to see which ones cooled off the fastest. Keep in mind this was with each pot full, seeing which pots cooled off when empty probably could've been done more quickly and I'd be surprised if the order was any different than it is here, but I digress.



There are the pots I chose; some new, some old - some thicker, some very thin. Different clay types, etc. I could say I tried to curate this selection, but really this was just what was laying around when the idea struck.

Here were the results:



So, suprise surprise, the biggest pot went the longest and the smallest pot cooled the fastest. Hence the "mostly pointless" part. Still, the way the tiaosha/zini pot held heat was impressive, and the F1s likewise did a pretty decent job given their thickness. The thinner zhuni definitely has its uses as a quick-cooling pot for certain teas.

No real amazing takeaway point or anything like that, but hey I already wasted all this time so why not share!

[LeoFox]

If you generated temperature curves, can you share them? also please include the volumes and thickness of the pots

[Victoria]

Welcome to TeaForum and thanks for sharing your experiment @Benjamin. Curious what the difference in temperature/time/ml size was between the pots? That late Qing early Republic period zini tiaosha looks interesting too, I’d be interested in more info and images on that one, looks pretty thick.

[mbanu]

Volume is a secret ingredient, I agree! I think one reason people believe that green tea needs lower-temperature water is because they are brewing it in big (for green tea) teapots, where if they follow the instructions designed for smaller teapots, they end up with bad green tea.

[Victoria]

Volume is a secret ingredient, I agree! I think one reason people believe that green tea needs lower-temperature water is because they are brewing it in big (for green tea) teapots, where if they follow the instructions designed for smaller teapots, they end up with bad green tea.

If you are speaking about pan fried Chinese greens that makes sense. With Japanese steamed greens though cooler temperatures (130-170F) are more favorable in both larger and small kyusu in my experience. Although, I can see using even lower temperatures as the kyusu get increasingly larger, like at 350, 450, 550 ml. Another experiment

[Benjamin]

If you generated temperature curves, can you share them? also please include the volumes and thickness of the pots

I'm not that cool

Volumes, I can definitely post when I have a moment.

[LeoFox]

If you generated temperature curves, can you share them? also please include the volumes and thickness of the pots

I'm not that cool

Volumes, I can definitely post when I have a moment.

How about the starting and ending temps?

[Benjamin]

If you generated temperature curves, can you share them? also please include the volumes and thickness of the pots

I'm not that cool

Volumes, I can definitely post when I have a moment.

How about the starting and ending temps?

Didn't bother as I was only really interested in the general lineup of "most heat retentive" to least. I agree it would be interesting to measure the water right at the beginning, and maybe every 5 minutes afterward to get a more accurate understanding of what goes on. This was just my random off-the-cuff idea so nothing that methodical went down, but maybe next time!

[Victoria]

How about the starting and ending temps?

Didn't bother as I was only really interested in the general lineup of "most heat retentive" to least. I agree it would be interesting to measure the water right at the beginning, and maybe every 5 minutes afterward to get a more accurate understanding of what goes on. This was just my random off-the-cuff idea so nothing that methodical went down, but maybe next time!

We can call this thread Heat Retention Experiment(s) if someone wants to do this experiment logging;
teapot volume ml/thickness of vessel wall/temperature every 2 minutes

[Benjamin]

How about the starting and ending temps?

Didn't bother as I was only really interested in the general lineup of "most heat retentive" to least. I agree it would be interesting to measure the water right at the beginning, and maybe every 5 minutes afterward to get a more accurate understanding of what goes on. This was just my random off-the-cuff idea so nothing that methodical went down, but maybe next time!

We can call this thread Heat Retention Experiment(s) if someone wants to do this experiment logging;
teapot volume ml/thickness of vessel wall/temperature every 2 minutes

Definitely, I'd be interested to hear others' experience. My selection is too small to come to any great conclusions, but was done mostly to assess which of my pots would be good for which of my teas. Something more objective would definitely be a welcome contribution.

[Youzi]

I'd equalize for peak temperature. Otherwise you are mixing the two together. Maybe one teapot cools much faster than another, but because it reached a higher leak temperature, then it seems like it has better heat retention.
(typically the case with thin vs thick teapots)

Also if you don't measure the teapots separately, then preheating introduces more errors into your measurement, and it's also not really realistic, because you can only preheat at the beginning and the very end of a session, and unless you are using really small pots, you can't really keep up with the pots being fully heated all the time.

[Benjamin]

I'd equalize for peak temperature. Otherwise you are mixing the two together. Maybe one teapot cools much faster than another, but because it reached a higher leak temperature, then it seems like it has better heat retention.
(typically the case with thin vs thick teapots)

Also if you don't measure the teapots separately, then preheating introduces more errors into your measurement, and it's also not really realistic, because you can only preheat at the beginning and the very end of a session, and unless you are using really small pots, you can't really keep up with the pots being fully heated all the time.

Sure, makes sense.

[Bok]

unless you are using really small pots, you can't really keep up with the pots being fully heated all the time.

Bingo!

: )