24 Comments
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testingthewaters's avatar

A nice experiment, well done. If you ever follow up with additional factors, may I suggest a response surface method such as central composite design? A reasonably efficient way to add in some complexity without your home overflowing with tea cups and schematics.

https://en.wikipedia.org/wiki/Central_composite_design

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Julia D.'s avatar

I hope your pyramidal teabags are not the type I've seen which are made of plastic mesh. Those release a lot of microplastics (and I would assume plasticizers) when heated to tea temperatures.

https://pubs.acs.org/doi/10.1021/acs.est.9b02540

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dynomight's avatar

I appreciate that! But no, I never buy tea in those plastic bags and PG Tips thankfully makes paper pyramidal bags: https://www.telegraph.co.uk/foodanddrink/foodanddrinknews/10984110/Pyramid-tea-bags-better-than-round-advertising-watchdog-rules.html

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Julia D.'s avatar

Oh good! It seemed like the sort of thing you'd share my concern about, given your attention to bad particles in air (ultrasonic humidifiers, air purifiers). I'm glad your tea is safe.

At the risk of lightly sprinkling on your parade, while I was searching for a quality link to support my comment above, I ran across claims that even some brands of paper teabags have plastics in them, with some of the same concerns. I was previously unaware of this. We drink a fair amount of herbal tisanes. I'm not sure at this point whether to switch to the brands that claim they've eliminated plastics from their paper teabags, or to switch to loose-leaf, or to ignore it until the problem goes away since it might be minor and it seems the trend is to fix this issue.

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dynomight's avatar

No worries. Truth be told, I drink loose-leaf tea probably 95% of the time. I only used bagged tea for this experiment because I wanted a very consistent amount of a widely available tea and be easy to reproduce, etc.

Edit: FWIW I intellectually tend to be not *that* worried about exposure to plastics in diet. Though I still avoid them as much as possible (at least in cases like this, where it's easy).

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matt bee's avatar

I admire Subject B's granularity, and I find their data the most plausible. In science you rarely see perfectly round numbers like 3. Good job, Subject B

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Riley Haas's avatar

I don't like hot things so I brew my tea, walk away (it steeps forever) and then I eventually drink it when I can handle the temperature. I then (shock, horror) reuse the tea bag 1-2 times depending on the day of the week.

I'm going to have to try this because maybe I'd like it even more if I brewed it at 80 (or even lower) and then drank it with less steeping. Somehow it never even occurred to me to brew black at a temperature I'd brew other teas at.

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Pjohn's avatar

I have (as will become clear..) Many Opinions about tea, and I am very doubtful of these results!

1) Considerably stronger results (..and possibly also stronger tea..) should be needed to overturn a lifetime's experience in making and drinking tea, not to mention the existing literature:

Douglas Adams' "How to make tea, for Americans": https://hatterstea.wordpress.com/2011/04/21/douglas-adams-on-tea/

George Orwell's "A nice cup of tea": http://www.booksatoz.com/witsend/tea/orwell.htm

(I can wholeheartedly recommend both essays as being essentially right-headed about tea-making..)

2) The tea mugs weren't warmed with boiling water beforehand - as every English grandmother will tell you, one must warm the pot before making tea in it. This effect probably scales with temperature, so the boiling water was probably cooled by the mugs more than the 80°C water was.

2.5) (Speaking of English grandmothers, they will also tell you that one brings the pot to the kettle, never the kettle to the pot: the English grandmother vote is definitely on the side of actually-boiling water, here...)

3) Even a small quantity of sugar obscures the taste of tea, even very strong tea, so overwhelmingly that the "with sugar" results for all categories (except possibly "aroma" - unsure about this one!) are likely tracking micro-variations in the sweetness of the tea rather than the actual flavour of the tea.

3.5) (Also, as any Indian grandmother will tell you: when one adds sugar, even a single granule, one simply ruins a pot of tea!)

3.75) (For this reason, scoring sugar-flavoured tea more highly than tea-flavoured tea ought to have been a sufficient exclusion criterion for any participant...)

4) I would guess that all the participants were American - if so, I think this introduces a considerable bias. Specifically, I think the American palate genuinely is different enough from the palates of tea-drinking cultures that appreciating tea brewed the right way is probably a learned skill for most Americans, compared to nations wherein (in generations past, at least: not so much now) youths grew up drinking tea. (This works both ways round, I'm sure: to the British palate, pretty much all American stuff, from beer to chocolate, just frankly tastes ruddy peculiar!)

5) "Export" tea is often bagged differently: much thicker bags are used so that there's no chance of the bag splitting and no chance of even a single tea leaf escaping through a hole (both of these things are harmless - rather, as indicators of a sufficiently-permeable teabag, they can be a good sign - but for some reason export markets seem to be concerned with them over and above lesser teabag considerations such as permeability..)

(These 'export' bags are sometimes identifiable by being individually enclosed in sachets, or having a string and a cardboard tab attached, or having a slightly plastic-ey texture - none of which, by the way, contribute anything of value either to the flavour of the tea or to the tea-making process.) I suspect that these bags limit the infusion rate enough to confound the experiment: even brewing tea with "normal" teabags makes it come out weaker than loose-leaf tea - and if I make tea with the "export" teabags I have found that I usually have to put two in to get a reasonable strength tea - and I don't even drink my tea particularly strong!

6) The statistical methodology was flawed: obviously it ought to have been *puts on sunglasses* a t-test.

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dynomight's avatar

(1) I only claimed "very weak evidence" (2) The tea wasn't brewed in the mugs at all, but in a pre-heated (indeed continuously heated) measuring cup. (4) Bad guess!

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Pjohn's avatar

1) Acknowledged and agreed.

2) Sorry if I missed that - I withdraw this objection.

4) If you had subjects with palates that we might expect to be developed/attuned to properly-made tea, then I withdraw this objection also.

Thanks for the reply!

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dynomight's avatar

I actually think it's possible (2) could explain my results, but from the other direction? Since I was continuously heating the brewing vessel, it's possible the effective brew temperature was hotter than would be achieved even with water poured into a pre-heated mug. This would mean the best tasting temperature would be lower than typical. (Certainly if you didn't use a pre-heated mug, it would probably drop the temperature 10-20C over the course of the first couple minutes.)

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Pjohn's avatar

I don't think I understand what you mean by "the best tasting temperature would be lower than typical": d'you mean that if the best-tasting tea is brewed at 100°C then the highest-scoring brew would be (say) the 95°C sample which - assuming 5°C heating from the teapot - would be brewed closest to 100°C?

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dynomight's avatar

Oh, I just mean that 80C according to my brewing protocol is probably warmer than 80C as most people would brew.

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Rick Hull's avatar

Subject D seems suspiciously familiar with Substance T

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Katie's avatar

I also derive much of my joy in life from tea, and my hypothesis would be that I'd get the opposite results!

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dynomight's avatar

You should try it! Though note that I maintained the temperature of the measuring cup while brewing. So if you just poured 79C water into a cold mug, for example, the effective temperature would be much cooler.

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Shawn's avatar

Interesting, and I would be tempted to repeat the study except that I am such a black tea fan that I would suck a dry tea bag if that's all that was to hand.

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cmart's avatar

Unfortunately this is a high-dimensional domain. Brewing extracts different chemicals at different rates (modulo temperature and agitation), but also changes or volatilizes some of them in the process. Caffiene and aromatics come out early. Tannins come out later (which make over-extracted black tea taste like ass). Oolong and green teas can develop a nice pot liquor (i.e. the tea feels velvety or viscous) with more extraction, but in doing so you volatilize (and lose) some of the aroma. All of that interacts with everyone's individual preferences.

This seems to be why people who get into tea like to do several short brews of the same leaves (with small amounts of water). It's sort of a pointless exercise with fully-oxidized black tea, but takes you on a flavor journey with, (e.g.) a loose leaf oolong that was picked within the past year. At the end it can feel like a sweet and savory soup broth.

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dynomight's avatar

Agreed. Ideally you'd vary the tea (and the serving temperature and the brew time, etc.) The main reasons for using a semi-crappy black tea were (1) that it's "standard" and (2) that everyone knows you should brew oolongs and green teas a lower temperatures but most people would (I think?) think that PG tips should be brewed with boiling water.

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cmart's avatar

(dynomight can I send you some tea?)

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Evan Fields's avatar

Since subject D is so obviously so well calibrated, it'd be interesting to see them rate a wider range of brewing temperatures, presumably discovering some optimal temperature. Or maybe the linear trend continues forever and we should all brew our tea at 0.1C!

(Double bonus points for doing this with a nice oolong...)

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dynomight's avatar

I assumed that 79C was cool enough that it would be below-optimal, but that didn't seem to be the case. I might do some more experiments, but the randomization and blinding is just so annoying when you need to serve everything at the same temperature. (Maybe I should just make all the teas and stick them into a constant temperature oven or something...)

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Tommy C's avatar

I am mildly shocked that sugar makes practically no impact on your overall score! Maybe even more intriguing is that it improved the flavor at low temps, but worsened the flavor at moderate temps. Do you normally add sugar or not?

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dynomight's avatar

To be fair it was a very small amount of sugar, so little that subjects A-C weren't even sure what was different.

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