ISO3103 Tea Preparation [pdf]
sis.se
sis.se
- this is for commercial tea, not specialty or "ceremony" grade tea
- all of the big commodity houses, blending houses, brand buyers, etc have their own modifications on the standard, and this ISO tea prep standard is most definitely not the "standard"
- From elsewhere in the thread: all great tea can be brewed with boiling water. The idea that green tea (or any other type of whole leaf tea) should be brewed with something under ~100C is a technique used by merchants to sell you bad tea.
[0] www.gastrograph.com
[1] teatechnique.org/
Is this "can be brewed" as in you will end up with a beverage that is drinkable, or that you think that in general green tea is fine to be brewed at 100C. The former I can understand (especially with cheap bagged green tea) but I'd be very surprised at the later considering that goes against pretty all modern and traditional guidance I've heard or read.
Longer Explanation:
In the Chinese tea tradition, water temperature is referred to by the size of bubbles during boiling (crab eyes = small bubbles (cooler) vs fish eyes = large bubbles (hotter)).
In theory, all water at boil is 100°c, but in practice, there is often a temperature gradient within a kettle and only the gas (the bubbles) is at exactly 100°c (assuming you're at sea level), which is why even some culinary recipes will call for a "rolling boil".
In any case, the strength of the stream when pouring will have a greater effect on the resulting flavor profile of very good green tea than the variation in bubble size, as bubble size is a variance of ~2°c while water can lose up to 5°c in a high slow pour.
Thus, boiling water at crab eyes with a thin slow (but not high) pour is the method used for high end Chinese green tea amongst high level Chinese tea practitioners.
Plus there doesn't account for other green teas that aren't poured in accordance with Chinese tea ceremony, such as the Nepalese green I had earlier today.
Yes, the general idea is to adjust your boil and pour method for the type of tea you're brewing, but that is true for all tea. Water will lose the same heat under the same conditions whether you're brewing oolong or green tea.
To summarize the points addressed here:
- High-end Chinese green tea can be brewed with "boiling water" just as oolong or black tea can; the adjustments are within the range used for other classes of tea.
- Merchants recommending cooler water for green tea do so to reduce the astringency and/or grassy flavor found in lower quality tea.
- Nepal does not have a historical tea tradition and the cultivation of Nepalese green tea is a modern development. Nepal inherited its tea habits from India whom had it imposed on them by the British who stole the seeds from China. While Nepal produces good tea on par with Darjeeling, it does not compare to the highest end Chinese green teas, which are an order of magnitude more expensive, if not more.
What accounts for this difference?
High-end sencha is steam processed at a lower temperature. Steam only gets to ~100°c depending on altitude and that is the highest temperature it is exposed to throughout its production.
High-end Chinese green tea is partially processed in a wok to denature the oxidizing enzymes. The saying for Chinese tea is that "tea remembers the heat of the wok", which is the pan frying process at upwards of ~200°c.
So all wok processed green tea can be brewed with hotter water than steam processed green tea.
Certainly this is how the old coworker who had a paper copy pinned up behind their desk explained it to me, and that understanding was why they found its existence so amusing even if their preferred cuppa's preparation process was substantially different.
This could of course be entirely wrong but seeing the paper copy pinned to the wall always did make me smile.
My point was that outside of the most commodity level tea sourcing, no one uses these "standards".
To illustrate this:
Just as coffee has "cupping", a method of preparation used for sourcing and evaluation but which no consumer would ever use to prepare coffee for enjoyment....
Commodity tea has this ISO standard (also called cupping).
The reason that this method, over a method that results in a better tasting cup is used, is because commodity tea is selected via flaw minimization and consistency testing.
I'm unsure why you presented the entire point of the conversation as if it was a gotcha, but assuming it was a genuine mistake I can only suggest that you read my comment again.
https://www.orwellfoundation.com/the-orwell-foundation/orwel...
Both with and without milk? Must be how Zen monks drink it.
That would make a bitter cup of green tea. Green tea infuses best at 80 degrees and the time is dependent on the tea.
Green tea taste follows a bell shaped curve, there is a small window of about 10 seconds when the brew is best, you got to stop it precisely at the top. You can use a thermometer and a watch, but the easiest is to just take a sip of the brew every 30 seconds.
Black teas, oolong and puerh can handle 100 degree water and are not as fussy about timing.
Also, green tea is just fine at boiling, if it isn't of poor quality :)
It was part of the quality control at the tea blending / packaging factory. It ensures repeatable consistency. It's not supposed to be the best taste, or follow some tradition or style.
It is the tea equivalent of checking the strength of cement, or measuring the brightness of a light bulb.
Black tea - 95 C
Oolong Tea - 80-90 C (depending on oxidation level, more = higher temperature)
Green Tea - 75 C
Yellow Tea - 70-75 C
White Tea - 70 C
Using boiling water will scald the leaves and leave a bitter taste.
Fun fact, tea is technically only the leaves of the camellia sinensis plant, all the permutations of black, green, white etc teas are how the leaves are processed by humans after cultivation, they're not different species of the plant. Any "teas" that are not of the camellia sinensis plant are technically called tisanes, although in colloquial usage no one says tisane.
As an example, I use a glass teapot with 1 liter of water. I preheat the water 4 minutes (@ 1000 W), I add the tea bags, then I heat again for 2 minutes 10 seconds.
Obviously the precise times will be different for other microwave ovens and teapots, but the point is that with a microwave oven you can experiment with fine adjustments of the time until you get what you deem to be the best taste.
Once optimal times are found, the process will be perfectly reproducible, so you will obtain the best taste every time.
I have transitioned a couple of years ago from making the tea on a traditional gas stove to using the microwave oven and the result was much better tea tastes that are always the same.
Controlling the time in this case controls the temperature, but it is more convenient than attempting to control directly the temperature when using other cooking devices.
https://en.wikipedia.org/wiki/Superheating#Occurrence_via_mi...
I've personally never encountered this with water, but have seen it happen with diethyl ether and dichloromethane (at ~40 deg C, so much less scary)
I'm not (just) being facetious - I don't think it can be well answered, because you're obviously thinking of something specific, and someone's going to answer with their own probably different specific 'herbal' tea in mind.
In any case, there are a lot of different herbals and the perfect water temperature might be different for all of them. When I drink herbals (rarely) I just use boiling water.
In Swedish, the word for non-tea tea is "örtte", where "ört" means "herb". Very confusing.
It's so simple, I can't believe all these comments arguing over something so subjective.