Teaberry and partridgeberry tisanes (natural wintergreen herb tea)

 

teaberry!  aka wintergreen.

partridgeberry; smaller, rounder leaves.

I've long since been intrigued by the possibility of making an herb tea / tisane from teaberry leaves, or at least a plant type I grew up knowing as teaberry.  In reviewing background for this post it turns out that two different local plants--that are common where I'm from, Western Pennsylvania, where I visit now--are both probably referred to as teaberry, when one is a variation of partidgeberry.  Or so a couple of online sources indicate; it's hard to drill down to the absolute fact of the matter in online references.  

Let's start with what I understood, beyond picking and eating what I took to be teaberries.  I've read different accounts about using teaberry as a tisane, including a claim that it oxidizes well, as "real tea" does.  Here is more background, from the book "Secrets of Native American Herbal Remedies:"

Wintergreen (Gaultheria Procumbens) is an aromatic evergreen shrub native to North America.  Also called Canada tea and deerberry, wintergreen is often used to relieve pain and inflammation.  The leaves of wintergreen contain methyl salicylate, which is closely related to aspirin.  Several tribes, including the Delaware and Mohican, have used a tea made from the leaves to treat kidney disorders.  The Great Lakes and Eastern Woodland tribes have used poultices from wintergreen, applying them topically to treat arthritic aches and pains.

That hadn't really the basis for my interest, but it was interesting.  Wikipedia adds this, about teaberries:

The fruits of G. procumbens, considered its actual "teaberries", are edible, with a taste of mildly sweet wintergreen similar to the flavors of the Mentha varieties M. piperita (peppermint) and M. spicata (spearmint) even though G. procumbens is not a true mint. The leaves and branches make a fine herbal tea, through normal drying and infusion process. For the leaves to yield significant amounts of their essential oil, they need to be fermented for at least three days.

teaberry leaves with moderate bruising, not nearly enough to enable oxidation

teaberry leaves bruised and chopped

It was partly this oxidation potential that made it interesting.  This Youtube video clarifies the difference between partridgeberries and teaberries, confirming that both are edible, as fruits (berries) or leaves.  That correct identification helps explain why the partridgeberry fruit is a little bit minty but the leaves aren't overly so.  This Youtube video passes on guidance for finding and identifying "real" teaberry.

This plant source covers more background, about that second plant type:

Mitchella repens, Partridgeberry, Partridge Berry, Native Bare Root Perennial

A trailing, evergreen herb with white, fragrant, tubular flowers in pairs. Partridgeberry is a creeping, perennial herb, no taller than 2 in. high. All parts are dainty, including its pairs of small, rounded, evergreen leaves; tiny, trumpet-shaped, pinkish-white flowers; and scarlet berries.

A most attractive woodland creeper with highly ornamental foliage, it can be used as a groundcover under acid-loving shrubs and in terraria in the winter. The common name implies that the scarlet fruits are relished by partridges, and they are consumed by a variety of birds and mammals. Indian women drank a tea made from the leaves as an aid in childbirth.

No one brews an herb tea / tisane from either of these plants where I'm from, typically; the teaberry name isn't necessarily taken as an indication that drying and brewing the leaves would be a great idea.

I've tracked down both, growing right beside my parents' and brother's homes, and have made a tisane out of both (attempting some rolling of the leaves, then drying them).  At time of writing an early draft I've only brewed the teaberry leaves, but I will write this related to trying the other.

Teaberry tastes minty, as this one passage suggests; the leaf flavor really is "wintergreen."  The teaberries don't taste that much like the leaves, but there is some overlap.  I'll skip adding more on partidgeberry character in this intro section, but related to tasting fresh leaves they just taste a bit vegetal, without much flavor coming through at all.

Preparation and review:

I tried out bruising / rolling the leaves to support oxidation, but it didn't seem to have much effect.  I'm not sure that the compounds in these leaves are right for this transition (either of them, really), or if I just didn't bruise them enough.  I suspect using a mortar and pestle and really grinding the leaves a bit would help, where I just tried rolling the partridgeberry with a rolling pin, and pounding the teaberries with a mallet for tenderizing meat, then slicing those into thin strips, to support more air contact to internal leaf compounds.  Onto review notes then.

teaberry / wintergreen brewed on the lighter side

Teaberry:  it tastes like wintergreen.  For some people that's all I would need to say, if that mint flavor range is familiar.  It's less peppery than peppermint or spearmint, but closer to spearmint for being milder.  It's quite sweet and pleasant.  I didn't use enough to really dial up infusion strength, maybe 3 grams for two rounds of Western style brewing, but it was enough to see how it would work out.

It seems odd breaking that down further.  It was minty, along that particular line for flavor, wintergreen.  There's not much to add.  There was no astringency, or vegetal range character.  I suspect that variation and depth could be had by properly oxidizing the leaves, but I'm out of time to experiment with that here, and I'm not carrying fresh plant leaves back to Thailand.  I could rapidly dry some, skipping an oxidation step, but I've already tried that prepared herb version.

I brewed the leaves twice and mixed the mostly spent leaves with partly brewed out black tea, from breakfast, and the resulting mix tasted strongly of that one mint note, in a pleasant way.  Apparently they had more to give.  Simmering the leaves might be promising, really forcing flavor extraction.  Or there's a masala chai trick of simmering tea and herbs, letting it sit, re-simmering it, and letting it sit again, resulting in brewing at or near boiling point temperature for an extended time.

Partridgeberry:  there is a trace of mint, but not much, and beyond that the vegetal range flavor is a bit subtle.  It doesn't taste like much.  It's nice that it can be used as a tisane, and I suppose it could be helpful if it really does have medicinal qualities, but related to the experience of drinking it there just isn't that much going on.  Teaberry leaves as a tisane are interesting and pleasant, but partridgeberry leaf isn't.

One might wonder why I'm going on and on about plants that produce berries in relation to brewing the leaves, and leaving the berries out of it, not brewing those.  They're not berries in the sense of strawberries or raspberries; they're subtle in character.  Teaberries are pleasant, sweet and minty, but partridgeberries don't taste like much at all.  Teaberries aren't really flavorful enough to be promising as a tisane, brewed alone, although maybe I'm wrong, and that might work.

There's one mystery left in all this, related to ligonberries, which are described as the same thing as partridgeberries in some references.  How is this possible?  Ligonberries are relatively similar to cranberry; they should be quite flavorful and tart, but these are almost entirely flavorless.  Two possibilities come to mind, but there may be others:  these aren't really a variation of ligonberries (or just that, called a different name), or they are related but it's a plant type variation, that isn't identical.  I don't know, really.  Intensity could vary by season, related to time of the year, but surely not as much as this, to cause a strong-flavored berry to be flavorless some of the time.

At any rate the one plant people refer to as teaberries locally really is that, and its berries are sweeter and more flavorful, with the leaves "wintergreen" in flavor.  The other doesn't taste like much, as berries or dried and brewed leaves.

Family visit photos, back to Western Pennsylvania

As I'd mentioned I've been in Western PA, visiting my family.  These notes, and most of the text, is from that visit, and I finish the editing while traveling back to Bangkok again.  I won't add much more about that, but I will share some photos from there.

view from a balcony at my parents' house

the colors change fast; this was two weeks later

a hunting lodge sort of theme

again earlier in the stay, a creek beside their house

not much later, showing more color

my kids and two cousins

meeting those kids was a main highlight (and one other); it was hard leaving them

Bi Yu and Lishan Taiwanese rolled oolongs

 

I'm reviewing two very interesting and pleasant Taiwanese rolled oolongs, from Tea Mania, a vendor based in Switzerland.  Peter, the owner, passed on these samples in a visit awhile back (many thanks).  There's a lot to say about them so I'll cite the product listings for more background and get on with the review notes section.

I might first add that I was really more into rolled oolong scope very early in tea exploration; it's essentially where I started, checking out Thai versions that were around (in Bangkok).  Variety and quality scale is pretty broad, and it's my opinion that the best versions come from Taiwan.  I tried a pretty good more oxidized and roasted Tie Guan Yin, from Anxi, China, not too long ago, but these are something else.  Thailand can make ok versions, and Vietnamese range can be better than Thailand's, really extending to the top of the Taiwanese quality range in the rarest cases, but it could be hard to find those best of the best versions from there.

Bi Yu  (15 CHF or $17.63, seemingly for 50 grams)

Bi Yu is a rare Taiwanese cultivar that descends from the well-known Qing Xin and Jin Xuan cultivars. The aroma profile of Bi Yu lies between the two parents, Qing Xing and Jin Xuan. A decisive difference is the pronounced fruitiness which is underlined by floral notes.

Due to the traditional processing, it can be stored without any loss of aroma. With increasing age, the aroma changes and develops its very own charm.

Harvest date: spring 2021

Aroma: fruity, with light, floral notes on the finish

Oxidation: approx. 40%

Roasting: middle

Terroir: Mingjian, Nantou, Taiwan

Lishan Gaoshan Wulong (30 CHF or $35.25 for 50 grams)

Lishan Gaoshan Wulong is a slightly oxidized, bouquet style highland tea from Lishan. Due to the slight oxidation the tea has a very floral and refreshing character, which reminds of the floral in the green tea, but due to the processing as wulong tea it has a much stronger body and is a much more intensive taste experience. With the slightly oxidized wulong, the leaves are not shaken as much, but are handled much more gently. This means that there are no red leaf edges, which makes the tea taste much more floral and refreshing. The infusion in the cup is also much brighter. The reverberation in the mouth is still clearly perceptible even over a longer period of time and it is a pleasure to trace the character of the tea in meditative silence and to fathom its complex character more and more.

Lishan Gaoshan Wulong is not roasted and only slightly but nevertheless well oxidized. Thus the character of highland teas is clearly visible. Due to the traditional processing it can be stored without any problems and without losing its aroma. With increasing age, the aroma changes and develops its very own charm.

Harvest time: spring 2020

Aroma: floral, with notes of osmanthus and honey

Oxidation: approx. 20%

Roasting: non

Terroir: Lishan, Nantou, Taiwan

Note that these are from different years, 2021 for the Bi Yu, and 2020 for the Lishan, and oxidation level is higher for the Bi Yu, with only that version roasted.  I don't speculate about those inputs in these review notes (I checked the descriptions and added them later in editing), focusing on the experienced aspects instead.  Even that tends to run long.

I've researched and written quite a bit about Taiwanese cultivars in this blog, just nothing for the last half a dozen years.  I'll also skip going into any of that, but anyone interested could search it up here.  One reference I cite in those posts covers what the older plant types and newer hybrid cultivars are.  Jin Xuan is an example of the newer range (#12 in that series), as Bi Yu must be.  Qing Xin is really a range of more original plant types, not just all one thing genetically, according to this research study reference.

this post covers more about this, with the table from this reference

Bi Yu left, in all photos

Review:

Bi Yu:  it's quite good; I expected that.  There is an intensity of floral range and mineral base that's distinctive across most Taiwanese rolled oolongs, and this expresses that.  Floral range is intense and complex.  A mineral base is harder to notice but that is what helps ground the rest, making it come across as a very complex experience.  

Intensity is good, on the high side.  I brewed this for longer than a typical infusion to get it started from still completely dry and compacted, for 30 seconds or just over, and it's not on the light side at all.  The effect is just as it should be.  

Related to regional character, tied to the origin, or the cultivar type, I won't be able to comment on what is or isn't most type-typical; I just don't drink that much Taiwanese oolongs.  I've had good versions before, but it will still even be hard to place these within the scope of the highest quality range.  It's quite good; that's all I can tell.  I may not be able to get much further than describing this as expressing complex floral range; it's not one of my things to list out 3 or 4 flowers this resembles.

Lishan:  interesting!  I had expected this to be pretty similar to the other version, but it's not.  It's creamier, and it includes a nutty sort of flavor aspect.  Plenty of sweetness and floral range too, but it's quite different.  A touch of vegetal range enters in along with the floral tone, and the rest, but it's limited, and hard to place.  That might either develop or else drop out, and then I'd have either some or no chance of describing it further.  Mineral is a little different in this too.  It's so heavy that it leans a little towards salt or metal, in a good sense.  Maybe that vegetal range links with a savory edge too, and I'm just not connecting the parts appropriately.  

In re-trying the first version after tasting this the aftertaste in the Bi Yu version extends longer.  It's really pretty close to what I expected this tea to be like.  Am I thinking of conventional Alishan character instead?  I'm not at all clear on tea production areas in Taiwan, and tea plant types also factor in.

Bi Yu #2:  I brewed these for about 15 seconds, probably long enough to draw out plenty of intensity.  I didn't have the best guess for proportion in these, having been mostly off rolled oolongs for awhile, trying only a few over the last year, but I guessed it would be a good bit, a gaiwan full, so on towards the 10 grams I might often brew at one time.  It's too much for many people's preference, but kind of familiar range to me.  It will limit getting far through a full infusion cycle of two versions.

Creaminess picks up.  Intensity would also, if it hadn't been so intense in the first round, but I think the added complexity makes it come across as stronger.  Feel is nice and rich, aftertaste range is extended and pleasant.  The main story is intense floral taste.  It's almost like that new car smell, but in a good sense, a little towards plastic of an unusual kind.  But it's heavy floral range instead, a theme that's quite familiar to anyone who has explored much above average quality Taiwanese oolongs.  

Is this an example of one of the most pleasant styles, and highest quality levels?  Maybe, at least towards that.  I've heard someone criticize Taiwanese oolongs for being too intense before, claiming that they're accomplishing that through heavy fertilizer use.  I'm skeptical that's true, but it's at least possible.  Then that leads me back to considering food issues; would we be shocked to learn that a producer is using fertilizer to grow our tomatoes or spinach?  It would be surprising if they didn't.  I love the idea of wild-grown, natural conditions produced tea as much as the next person, but I'm not hung up on it.

[later editing note]:  the product listing description places flavor range as mostly fruit, supported by floral scope, which isn't what I've interpreted it as here.  When the two themes mix in a tea it can be hard to sort out which provides more input, and what you expect can factor into judgment.  If I had read that description prior to tasting I'd have been discussing fruit tones, but without that it seemed essentially entirely floral to me.  The character would have changed a little over 3 1/2 years; it's hard to factor that in.

Lishan:  nuttiness is pronounced again.  There would be different ways to interpret that; others may not see this as tasting like nuts, and it's not exactly like nuts, just in that general range (cashews, I guess, or maybe macadamia nuts instead, or in the middle).  There is floral range as well.  

I'm not noticing even a hint of vegetal range, maybe related to brewing it so much lighter, but the mineral layer is still a bit savory.  It comes across as less full and rich in relation to the first tea really dialing up that range, but that's partly related to a comparison effect, not a gap in aspects.  I could imagine someone like either one of these more than the other, but to me the first is nicer, related to getting back to experiencing that really dialed up floral range experience again.  Pleasant mineral base, rich feel, and long aftertaste support that.

Bi Yu #3:  it would work to brew these lightly, using half the proportion that I am, and still moderate infusion times, and intensity would still be fine.  Nah; I'm dialing it up.  At least I am only brewing these for 15 seconds or so, but at this proportion that brews a strong infusion.  I think some of that relates to acclimating to young sheng intensity, which is hard to moderate, no matter how you brew it, so brewing oolongs or other teas lightly just seems thin to me.

Richness really stands out this round, and the floral tone picks up a bit of warmth, taking on a perfume-like character.  Or that also reminds me of cognac or brandy, one part of that range of experience, which I've not been through in decades, since I barely drink any alcohol, a few beers a year.  

Floral tone is heavier.  Someone more capable of describing two dozen distinct floral tone inputs would be offering a different list of them this round.  More like lavender?  Intensity has been great through all these rounds, and that's the same, it's amazing.

Lishan:  those earlier aspects settle and integrate in an interesting way.  It won't really work to describe how, exactly what I mean by that.  The nutty range is less distinct as that kind of form, and a base of what seems like less clearly defined vegetal range picks up, like a green wood tone.  Floral range is still pronounced.  It all integrates as one pleasant and unified experience more than it must sound.  Decent sweetness and bright intensity makes it work, along with a significant mineral base.  Again it seems less rich in feel with less aftertaste expression, but that's mostly in comparison with the other version.

It's interesting that the wet leaf appearance is so much greener for this version than the other, and darker.  Based on reviewing the listings (later) it's from the oxidation level being higher for the Bi Yu version, but that Lishan version seems extra green somehow, so deep and dark.

Bi Yu #4:  the progressive warming transition continues; this may be drifting just a little towards a spice tone range.  It's not there yet; maybe next round that kind of shift will be more pronounced.  Again the heavier floral range is nice.

Lishan:  maybe just a touch "greener," or it could be that I'm looking for that, after the observation about the color.  I think it's actually there too.  It makes this come across as really rich in flavor in an unusual sense, not really similar to green tea character, but I suppose it wouldn't just be a stretch if someone wanted to draw some limited comparison.  The grassiness and astringency edge isn't there, but then green teas do vary quite a bit.  Maybe more like a more savory version of one, that lacks an astringency edge.

That green part reminds me of a fresh forest scent, as much as green wood, which is how I've described it earlier.  It's like that heavy vegetal scent after a spring rain.  I suppose drawing a parallel with moss might actually make sense; it's clear enough how the different themes I'm mentioning connect.  Moss does represent the greenest and dampest fresh floral tone range, integrated with heavy mineral range.

Going back and re-trying the other version after this one the warming tones in the Bi Yu might be shifting a little towards a green wood tone, more of an actual version of that, not something comparable but different.

Bi Yu #5:  I think drinking this on the hot side emphasizes a connection to spice tone, and then in a few minutes once it cools that green wood link will stand out as much.  That's a subject I don't ever do much with, variations in drinking tea at different temperatures.  

Often I'll use two cups for making tea Gongfu style with breakfast, pouring it from one to the other one time per round, to absorb more of the heat.  I'm using a larger set of cups to prepare these, so they're drinkable right away related to temperature, but not so cool.

Lishan:  more of the same, really.  It's interesting how those heavy flavors combine, not so clearly linked to nuts range now (macadamia mostly, I guess), but combining a few dominant layers.  It's pleasant for how well it all integrates and works together.  And it helps that there are no aspects that seem like flaws, which it's easy to not explicitly notice.  

The other version is just a touch sweeter, richer in feel, and includes more aftertaste experience, but that's not really a flaw, just more positive supporting range associated with the first tea.  I suppose that someone could interpret those as "quality markers," and see it as indicated as higher in quality, but it's hard for me to conclusively conclude that.  They're just different in style.

Later rounds:  these kept going and going, of course.  In later rounds the Bi Yu faded to become thinner in profile, with more emphasis on the heavy mineral layer.  The Lishan stayed quite positive, lightening up across aspect scope except for sweetness, bright floral range, and rich feel (so forest scent / vegetal range and the mineral layer dropped out, put the other way).  It was interesting for a tea to fade in the end while retaining the most positive aspect range; usually they'll pick up a woodiness, or settle on more mineral range.

Conclusions:

It's interesting not noticing fruit from the Bi Yu vendor description, it just seeming floral.  And interesting that the version really held its own with the Lishan up until later rounds, after which the Lishan continued on as more positive.  How to place that?

One might conclude that the Lishan is a higher quality level tea, or instead that the effects of higher oxidation level and roast input lent themselves to being more positive in earlier rounds, and then to the Bi Yu version fading quicker.  Maybe it's both.

For sheng pu'er, or even for other tea types, it's easier for me to place how the different types of aspects get sorted out according to somewhat conventional preferences, from discussion of teas online, or related to vendor input.  Are the heavy green forest scent / moss aspect or macadamia nut richness in the Lishan version highly desirable characteristics, or is that negative, or neutral?  I suppose preference should really dictate that, since specific flavors don't typically serve as "quality markers."  Something like richness of feel or extended aftertaste are more often regarded as universally positive. 

It would be nice if I'd kept up more contact with rolled oolong scope, and I could do better with placing these on a general quality scale, or commenting further on value.  At a guess they're quite good, matching up well with teas sold as of exceptional quality, and 30-some and 60-some cents a gram are very fair price ranges, for what they are.  For as pleasant as this Bi Yu version is that's probably a good value, as good rolled oolong goes, but then in a different sense that could easily also be true of the other Lishan version.  

Origin area is one main input to demand level, across many tea types, and you end up paying more for what other people tend to seek out and value.  Then styles and quality level can be more variable across less demanded range, so you have to be careful about what you explore, or some experiences won't match preferences and expectations.

Looking at their Taiwanese oolong page they carry a lot of versions.  It would be tough to pick and choose among them on a tightly limited budget.  Some might seem better than others, varying with preference, but at least of what I've tried of Tea Mania versions they've all been pretty solid, with no "misses."  That would happen, if a vendor is sharing their favorite versions as samples, but I was in the habit of buying tea from them every year awhile back, before I moved on to focusing on Thai and Vietnamese teas more recently, and all that I tried was quite nice.  

You do experience more misses when exploring off-main-production-area teas, and styles vary more, so you pay a price for buying teas at lower rates.  To me that variation is nice too though, experiencing what you don't expect.

How much theanine is in tea?

 

I just looked this up related to someone bringing it up in a biohacking group, of course related to taking it as a pill supplement instead of drinking tea.  Those people love supplements, the more experimental the better, it sometimes seems.  Theanine should be harmless enough, in a normal dosage range.  But what is that?

WebMD says this; they would never steer you wrong:

L-theanine is naturally found in tea and some mushrooms. As medicine, L-theanine has most often been used by adults in doses of 200-400 mg by mouth daily for 4-8 weeks. Speak with a healthcare provider to find out what dose might be best for a specific condition.

People in that group said that 100 mg is probably ok for a starter dose, but if they mean to take that twice a day it's back to 200.  It would depend on why someone is taking it.  WebMD says this:

Possibly Effective for:  Memory and thinking skills (cognitive function). Taking L-theanine by mouth might help healthy people stay focused. It isn't clear if adding L-theanine to caffeine works better than using either of those ingredients alone.

There is interest in using L-theanine for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

Healthline said this, more in line with what those people in that group were using it for:  

It’s said to help ease anxiety, stress, and reduce insomnia.  Before trying it out yourself, learn more about the potential health benefits, as well as any possible risks or complications.

So those two not so reliable, light content health sites said completely opposite things; that can happen.  People in that group thought that it could provide different benefits, and were taking it for different reasons.

So how much is in tea, especially in relation to standard supplementation amounts?  Scanning a few sources turned up different measured amounts, but this seems kind of middle of the road for other results:

Theanine and Caffeine Content of Infusions Prepared from Commercial Tea Samples

Materials and Methods:

Theanine and caffeine contents of 37 commercial white, green, oolong, black, and pu-erh tea samples were quantified by high-performance liquid chromatography-diode array detector.

Results:

The mean L-theanine content of white, green, oolong, and black teas were 6.26, 6.56, 6.09, and 5.13 mg/g, respectively. The same values for caffeine content were 16.79, 16.28, 19.31, and 17.73 mg/g.

So just over 6 mg per gram of dry tea.  The caffeine values seem normal enough; measured amounts typically ranges between 15 and 25 mg/g, so maybe a little on the low side, but these are "commercial" products, probably low to medium low in quality level.  Both theanine and caffeine range might bump a little in relation to testing or consuming slightly better tea, but probably not too much.

Extraction rate could be a little clearer, but it seems to follow the same pattern as for caffeine, so for a relatively complete brewing process something like 90% may be extracted, possibly a little less:

So from there it's really down to daily intake, amount of dry leaf prepared per day, which is going to vary for everyone.  Someone could brew two rounds of tea a day and consume 10 grams, but I tend to brew 9 or 10 grams for each Gongfu brewing session.  10 grams at 6 mg / gram of extraction (which may be slightly lower) is 60 mg; not a lot, in relation to taking supplements, which again might be in a range of 200 mg per day (taken as pills), but that would just depend.

It's interesting that they seemed to test one pu'er sample and found no theanine in it.  That could be an anomaly, or it could be that they tested shou pu'er and fermentation really does transition that compound to become something else.  Here is that summary:

Those results are all over the place.  There may well be a correlation between theanine levels and buds and fine leaves content, versus older leaves, as there is for caffeine level, but you can't really spot an underlying cause input from this kind of list.  It would seem natural for there to be a divide between variety Sinensis and variety Assamica plants, but this definitely wasn't set up to isolate that input, or any other, really.  One sample of any given type doesn't even tell you with any certainty that other samples of the same type would follow the same pattern, and have a similar amount in them.

For me it's enough to have as a guess that we might be ingesting around 6 mg per gram of tea, since I'm not even sure what theanine would do anyway.  There's a vague understanding that it calms you while caffeine gives you a lift, so I guess a very mild speedball effect, but not much of one.  The effect would be limited if your daily consumption probably lands between 60 and 120 mg per day, and only that higher level based on drinking 20 grams worth of tea a day, which is a lot.

I glanced at a couple of other studies and they're in this general range, with some showing some black tea amounts that are a good bit higher (in this study example):

High levels of milk resulted in a marked lowering of the level of detectable l-theanine. Contrary to previous research, a standard (200 ml) cup of black tea was found to contain the most l-theanine (24.2 ± 5.7 mg) while a cup of green tea contained the least (7.9 ± 3.8 mg).

So their findings were way off that other scale, which is more typical of what other sources that I looked through were saying.  It can be confusing comparing amount per brewed cup with a derived amount per gram of dry leaf, which to me is easier to work with.  They seemed to be making tea from a standard 2 or 2 1/2 gram commercial tea bag, and then infusion time surely would've been a limitation to extraction, since you don't brew tea bags for 10 minutes.  The point here is more that studies vary on general findings, as that one study varied quite a bit in relation to measured amounts and individual tea versions, even within type categories (black, green, and so on).

Someone could keep digging if they really wanted to know, but it would be hard to factor in what these studies are not testing for:  theanine amounts in relation to tea plant material type (buds, fine leaves, old leaves), and related to tea quality level.  Guessing that a final average experienced result is around 6 grams per gram of dry tea seems good enough, with extracted amount probably just below that.  

We're taking in a significant amount of theanine when drinking tea, just not getting dosed on the high side compared to the range of 100 mg to 400 mg of intake per day.  20 grams of tea--a good bit to drink in one day, which probably would exceed that 100 mg theanine input level--might work out to 20 mg of caffeine per dry gram of ingested tea, or 400 mg of caffeine per day, the general recommended daily limit.  

That is on the high side of most caffeine level test findings; 15 to 20 grams per mg is probably a more standard range, with extraction potentially between 85 and 90%.  My point in venturing into this second tangent is that it seems that you can drink 20 grams worth of tea per day, related to not exceeding a standard caffeine input level.  Then a daily dose of over 100 mg of theanine might offset some negative effects of caffeine, feeling "jittery," as people understand might happen.  It's not completely clear that would occur, but then theanine and caffeine aren't necessarily the only two active compounds in tea, the only two that would have any effect on how you feel.