Any insight into whether matcha drinking causes a higher risk of kidney stones? (Drinking matcha is consumption of powdered tea leaves, unlike nearly all other teas where the goal is to steep and then remove the leaves.)

Your oxalate reasoning suggests matcha would be worthy of study with respect to kidney stones but I've never that. I'm genuinely curious because research suggests consuming leaf solids can be very health-supporting in other ways. e.g. including kidney support to slow progression of diabetes, reducing blood lipid & glucose levels, etc.

https://www.ncbi.nlm.nih.gov/pubmed/19735169

https://www.ncbi.nlm.nih.gov/pubmed/26448271

Well oxalate levels between Black and Green tea is pretty huge it appears.

> black tea in tea bags and loose tea leaves were 4.68 and 5.11 milligrams per gram of tea. Green teas and oolong tea had lower oxalate amounts, ranging from .23 to 1.15 milligrams per gram of tea. http://blogs.webmd.com/healthy-recipe-doctor/2008/06/tea-and...

They may technically be the same species, but the cultivars/breeds can be very different. (Think about, say, dogs.) If you've spent much time drinking various kinds of tea, you know they can taste very different, and it's not just due to the processing: I've tried greens from Korea and India, black teas from China, oolongs from India and Thailand etc and different cultivars processed the same way do not taste the same way - they do not taste like their counterparts from Japan, India, and China respectively, even when they are advertising themselves as clones and attempting to taste as much alike as possible. Since flavor is due to differing levels of organic chemicals, if there are tastable differences, why not differences in levels of other chemicals too...

There are many cultivars but tea is even more sensitive in taste then say wine and grapes. Tea is very susceptible to climate and even harvest times. Darjeeling tea is my favorite but there are three different flushes. I prefer the less expensive second flush, but each one is taken from the same tea leaves and they all taste different. Darjeeling is of the same cultiver as all Chinese teas. Since Darjeeling is grown at such a high altitude and climate you can't get the same flavor in Chine though if someone figured that out they would be a multi-millionaire. Think the farmed caviar that is now hitting the market.

PS I love tea and the crazy things that happens with it, even in the same cultivars.

You're only further emphasizing why one would have to be crazy to not test tea varieties separately...

But I was talking about the same tea plant and the same variety.

Indeed. If you can get such differences in taste from the same variety and same exact tea plant, then the differences between different plants of different varieties in different countries harvested at different times to be processed different ways will be even greater, will they not? Making it even more foolish to not try to test different kinds of teas, and your criticism deeply misguided.

Black tea is delicious and other teas are gross - I assume some chemistry, however small, must be responsible for that difference. I think green tea always pops up in health studies because it's associated with cultures that are perceived to be healthier.

Japan is known for consuming almost solely green teas and therefore their research will be in green teas only. Intrestingly they grow most of their teas under shade which makes the tea sweeter.

Black tea gets a bad rap but black tea is just as healthy as green or white.

Also there are some great green and white teas, but their is such a difference in taste in the same types. Try a Jasmine Silver Needle for White and Darjeeling which is technically a Oolong (Its my favorite tea by far). Heck Indian tea is very different from teas from China. (I prefer Indian teas)

Green tea is more bitter because you have to use 165 degree water and not boiling water. 212 degree water makes green (and white) taste VERY bitter. Use boiled water on black since they don't shed the oil out of the tea leaf. Tea is so much more complicated then coffee.

I drink a fairly high amount of black tea (about 1.5L/day) and I had read about this before a bit, but couldn't find any clear answers - what's the risk of developing kidney stones and will I have fair warning signs before permanent damage?

I drink about 1L/day I use to get kidney stones all the time. Told to stop drinking tea and dark sodas. After researching it for 10 minutes my Urologist didn't know what he was talking about.

Contents of Oxalate:

black tea 15 grams for 1 liter equals 15 * 5.11 = 76.65 milligrams of soluble oxalates

Spinach has 645 milligrams of soluble oxalates per serving size!

Cola sodas has 0 as in ZERO soluble oxalates per serving size.

My doctor told me that was all new to him. I stopped going to him as a doctor. I ate spinach everyday. I stopped eat spinach I stopped having kidney stones.

Exactly what kind of tea do you drink? Is it iced tea, a brand?

You might be drinking too much. See http://www.livescience.com/50347-iced-tea-kidney-failure.htm.... That person was drinking about 2.5 times your intake but it might wise to throttle back a bit. You might not reach kidney failure but might reach levels that impair function or which leave you vulnerable to toxic oxalate buildup if you eat other oxalate rich foods.

I finally found a good study on this,

http://apjcn.nhri.org.tw/server/apjcn/11/4/298.pdf

"The results from this experiment show that while a regulartea drinker would be consuming oxalate every day, the levelsare modest when compared to the amounts of oxalate thatcan be found in other common foods. It would be verydifficult to consume an excessive amount of soluble oxalatefrom the regular consumption of black tea without milk. Theconsumption of black tea with milk would mean that smallamounts of oxalate would be absorbed on a daily basis andwould place black tea in the low risk group of foods, asdefined by Noonan and Savage".

Seems like damage is minimal and only some people will form calcium stones to begin with. For me this means I'm not going to make any concern out of it unless I hit an issue.

I did find one oft-repeated anecdotal case of a guy who consumed ~4L+ of iced tea per day and had more major issues, but I didn't see any other examples of this.

Citation for caffeine levels and the other numerous claims you're making up and down this thread?

White, oolong, puerh (both sheng and shu) are oxidized too I think, in different ways. Also purple tea is a bit different because of a genetic mutation.