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Hello,

I'm sorry if this was already asked a hundred times here, I'm new here, I tried to google my question to little success! I also thumbed through a few related threads here, but it was never quite what I was looking for.

I'm looking to buy two kyusu (kyusu? kyusus? ....kyusi? Plurals, huh?), one with a 120ml output, and one with a 240ml output --- Meaning, kyusu (A) is for either 2x60ml or 1x120ml cups, and kyusu (B) is for either 2x120ml cups or 3-4x60ml cups. I'm thinking two kyusu instead of one large one, because I've read that underfilling makes the tea bitter. But overfilling is also an issue, because of cramped leaves, and that's where my question lies!

My question is: How much space do I have to add for the leaves and handling? Is a 150ml-capacity kyusu enough for 120ml output of tea, or should it be even larger? Similarly, is 280ml capacity the right size for 240ml of output?
If I want to check the capacity of a teapot, would I measure that larger, room-for-leaves capacity (so, the 150ml or 280ml in my case) to-the-brim or at a reasonable fill level?

I'm not sure I'm making much sense, but I hope somebody gets what I'm trying to ask!

Thanks everybody

Welcome to TeaForum @PadMatt. Depends on the amount and type of leaf you introduce into the kyusu. Each leaf expands differently. For instance this morning I’m steeping Ippodo’s premium gyokuro in a 100ml Konishi kyusu; 10g/80ml/60c/90sec. First steep, I introduced 80ml water but the liquor output is just 60ml. Second steep, only 60ml water fits into the 100ml kyusu. Third steep just 53ml water fits, pouring out just 45ml into the guinomi, with squeezing the leaves 58ml. So I started with a 100ml kyusu, less 10g dry leaf, leaving 90ml available, yet on second steep only 60ml water will fit, so 10g of dry leaf has on second steep absorbed 30ml of water. Rocking and rotating the kyusu back and forth will extract a few more drops.

I’ll check later with a larger kyusu using sencha to see what the results are. Is there a particular reason you need a precise output?
I’ll add that output also depends on how dense or porous your kyusu is.

Some examples I have in my head

1. Porcelain roundish pot (measured several times with rolled oolong; I think it was the same with sheng pu-erh).

140ml water fits in the empty teapot
125ml water fits on first steep (6-8g dried tea inside)
100ml water fits on refills

(140ml to the brim; the 125ml and 100ml measurements are just below the brim, so I can close the lid with no more than a few drops of overflow)

2. Kyusae (just kidding--probably best to avoid using a Latin suffix for a Japanese word; pl. "kyusu" [using the unmarked Japanese plural] or "kyusus" look like reasonable choices to me, a non-native English speaker)

* 110ml flat kyusu, good for 70-75ml high leaf ratio sencha (measuring water only, incl. resteeps), 80ml is pushing it (might overflow on resteeps)

* 200ml flat kyusu, up to 150ml high leaf ratio sencha comfortably, 160-170ml uncomfortably (esp. if it's a sencha than can resteep many times--it will overflow after some steeps)

(high leaf ratio: 7g/100ml)

Overall observation: something like 70%(+-10pp) of the pot volume (measured to the brim) is "usable" for Japanese style brewing, as in: you can put that much water with wet leaf already inside w/o overflow. It depends a lot on pot shape: if it's a larger pot and narrow towards the mouth, you'll probly get closer to 80%. Also, some poorly crafted pots make a mess when pouring from what looks like "usable" fill.

So, if you want to pour in a constant 120ml of water for sencha (first steep will pour out significantly less, as the leaves absorb a few times their weight), then a 150ml kyusu (120ml/150ml=80%) will be cutting it close--might *just* work if it's not flat/wide mouth. My 200ml flat seems perfect for making 120ml (a 180ml should work just as well).

As to space needed to unfurl, I'm unaware of anybody having examined the question seriously (blind trial among several participants, published methods, etc.). You can read many opinions, but don't underestimate the capacity for self-delusion even among communities of experienced drinkers. My personal preference/self-delusion is for flat kyusus for sencha (could be more about thermal management & preparation habits rather than leaf expansion space; maybe visual and other aspects influence me, etc.).

Thank you both for the responses and examples, that helps a lot! From what I'm gathering here, is that I should skew upwards a bit more, perhaps 180ml and 300ml, instead of 150ml and 280ml.

@Victoria It's not so much that the output has to be precise, and more that 120ml and 60ml respectively are comfortable fill sizes for the cups I already own and love, and I would like to (best case scenario) have a kyusu that actually fits those in volume! I saw many recommendations for useful kyusu sizes in this lovely forum, but (from what I saw) they rarely talked about cup sizes in relation to those, and I would be sad if I spend upwards of a hundred euros on a kyusu that turns out to be too small for my cups, let alone two kyusus at double that

@teatray (Kyusae made me laugh. Thank you for that!)
So many detailed examples, lovely! Thanks!

I believed the "space needed to unfurl" thing blind, mainly because it seems to align with the common arguments against tea eggs! -- The strainer, I mean, not the food. But you're probably right in that I'm overthinking this a little and that a lof of it is self-delusion in the end


Thanks for the advice!

I just measured another, non-flat, 120ml kyusu after a few infusions (of 7g kama-iri cha) and only got 68ml of water (57%) in there, losing a few drops of overflow when closing the lid. The % was surprising to me--lower than what I wrote above. Maybe the numbers in my head were skewed by mainly measuring the first 2 infusions, or part of the explanation is that this pot's particular geometry/filter don't drain the leaves as well as my other pots.

@teatray Thank you for the further information and still thinking of my silly little question! :)

I actually got two lovely little teapots a few days ago which I am, so far, very happy with!
Turns out my measuring jug is inaccurate, and after using a gram scale, I found out that my two cup sizes are actually 60ml and 100ml, not 60ml and 120ml!

But since 2x60 is still 120 I stuck with that number, and decided on a 90ml houhin and a 180ml kyusu, with plans to maybe get a 300ml kyusu for company some other day in the future. I decided on the small houhin, because I realised that brewing 60ml in a 180ml kyusu would not be ideal temperature-wise, and I most often drink on my own anyway.
I get pretty much exactly one 60ml cup out of the 90ml houhin, and two 60ml cups out of the 180ml kyusu, or one 100ml cup with a bit of underfill (120ml would obviously still work, too. Not sure about more, I would have to try!). At least on first infusion for all of those, second and third is always a little less with each, but that's fine with me! The houhin is intended for gyokuro for myself, and the kyusu for gyokuro in company, or sencha for myself. The 300ml would allow for sencha in company, or a third person to enjoy gyokuro with, but that's dreams of the future...
They're both from Master Gyokko's workshop, and I am very happy with how they handle and with the sizes! In no small thanks to the help of you two, I would have bought a too-small kyusu without the input. :) Thank you! Whilst obviously there's always room for improvement if you're willing to pay even more, I think they're very well made, the lids fit very tightly and both have a very delicate, quiet water stream. No spillage yet! Both are unglazed, and the kyusu has a clay strainer.

@Victoria Tagging you too, because I want to thank you for your help too, and in case it interests you what came of this question :)

Congrats! Glad you found good ones on the first try! More about the potters running the Gyokko kiln: http://www.tac-net.ne.jp/~gyokko/syoukai.html [you can compare sig on the pots to the rightmost characters of the potter names in the section headings, switching back and forth between Japanese/English].

@PadMatt glad you are pleased with your new kyusu and shiboridashi. By the way, a hohin has a filter, whereas a shiboridashi is a simple lidded bowl sometimes with a few raked groves to help pass the drops along. A good explanation here by pedant, What is a Shiboridashi, Hohin, Gaiwan?. Since you posted this question I’ve been measuring my steeps on and off and agree with @teatray that +-20-30% of water is absorbed by Japanese steamed green tea leaves on first/second infusions. Also, you probably don’t want to fill your cups, I typically only fill 1/3-1/2, and you will most likely find yourself collecting teacups like clothing, switching between options and teas.