Sour notes in black tea

Oxidized tea
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LeoFox
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Sat Aug 13, 2022 9:41 am

This blog post suggests sour note in Chinese blacks is a fault due to over oxidation during drying that can be countered with high baking at the end:
If leaves are under-fermented, the final product would taste very “green” and grassy. If leaves are over-fermented, it’s very likely that the final tea soup tastes sour.
...
Drying requires heat, and heat needs to be created. If the heating up process takes too long, it’s possible that tea leaves get fermented again and develop the sour taste.

Therefore, in Tongmu tea-making, a unique step called “Red Pan” is used to prevent leaves from over-fermentation. “Red Pan”, or 过红锅 (pronunciation: Guò Hóng Guō, meaning: passing the red pot), uses heat to kill off enzyme activity to stop leaves from fermenting. (Yes, it’s very similar to “kill-green/杀青” in green tea and oolong tea.)
https://www.valleybrooktea.com/post/why ... taste-sour


On the other hand, the sunny dry hong from yunnan is expected to have sour notes that go away and transform with some age, as described colorfully here
I'm asking because when I was at our Fengqing tea farmer years ago and he was making his Yesheng Hong ( wild black ) , the fresh tea leaves were in big plastic crate covered by thick , but breathable , canvas. When he opened it , the disgusting sour ( almost like somebody had puked ) odor came out. ( the similar notes of sourness you can experience in fresh made Shai Hong - sun dried blacks , as they are not high heat processed after so these notes are imprinted in taste , yet they will diminish by some time and turn to sweet jam like taste )
viewtopic.php?p=41179#p41179

And it seems that the sour sunny dry may be more suitable for aging than those that get the high temperature treatment, which adds some choco notes, as hinted by this post:
Some of them have applied final high temp. roasting for short time , called “ti xiang” or “gao xiang” , that makes cocoa – chocolate hint in flavor spec. of the tea. There is also “shai hong” ( Sun dried ) processing of black tea, which is different from the previous two and it’s suitable for further ageing for certain time.
https://www.pageoftea.com/smart-tea-drinker


What are your thoughts on the sour notes in black tea?

Personally, I don't mind them as long as they are well balanced, and are more fruity than straight up sour.
Last edited by LeoFox on Sat Aug 13, 2022 5:57 pm, edited 4 times in total.
.m.
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Sat Aug 13, 2022 10:44 am

I enjoy sourness (i love lambic beer), so i wouldn't consider it a fault per se.

One tea with a pronounced sour notes that comes to my mind is the aged dianhong from TWL, where the sourness comes from the aging and i find it to be one of the strong points of the tea.

Other sour tea i've been enjoying lately is a black tea stuffed and aged in a pomelo/grapefruit, where the sourness comes mainly from the juices of the fruit, but there might be also from some additional fermentation notes.
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LeoFox
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Sat Aug 13, 2022 6:02 pm

.m. wrote:
Sat Aug 13, 2022 10:44 am
I enjoy sourness (i love lambic beer), so i wouldn't consider it a fault per se.

One tea with a pronounced sour notes that comes to my mind is the aged dianhong from TWL, where the sourness comes from the aging and i find it to be one of the strong points of the tea.

Other sour tea i've been enjoying lately is a black tea stuffed and aged in a pomelo/grapefruit, where the sourness comes mainly from the juices of the fruit, but there might be also from some additional fermentation notes.
Image
It's interesting how some preferences can transfer across different things but not others for me. Like you, I like sour beers, and vinegars, etc - in tea I don't mind them but I don't go out of the way to seek them out. However, while I like funky barnyardy wines - and once drove over 100 miles to get a bottle of one, I cannot stand it in tea.
Andrew S
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Sat Aug 13, 2022 6:09 pm

I also don't mind a hint of sourness, so long as it is the fruity / vibrant / refreshing kind, rather than something that makes me think the tea has 'gone off'.

That may be because I don't like black tea that tastes 'malty' or 'tippy'. For example, I never liked Yunnan dian hong because it tasted heavy, dense, rich, almost cloying for want of a better word, and it lacked the refreshing qualities that I've found in some Taiwanese black teas. Perhaps I was just drinking bad examples of Yunnan black teas, but even so, I've always preferred Darjeeling to Assam, so I think that I just prefer fruitier styles over heavier styles.

With aged wulong, though, I generally prefer a re-roasted tea over one which has gone a bit sour. That may reflect how I brew them harder than I brew black tea. But that might also reflect the different flavours I get from them. I find that yancha / aged baozhong etc can taste very refreshing on its own, so to say, whereas I feel that some black teas can benefit from a streak of fruitiness (or acidity, or light sourness) to overcome the heavier flavours that they tend to have.

Andrew
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mbanu
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Sat Aug 13, 2022 7:39 pm

Interesting topic for me, as I did not realize there was such a thing as an over-oxidized black tea from a Chinese-tea perspective. From the British-tea perspective, (at least to my understanding) all Chinese black teas are over-oxidized, as they are generally very soft and mild, but I suppose this perspective must have developed from somewhere.

I'm not familiar enough with the ins-and-outs of oxidation to know about non-fermented, non-age-related sourness in black teas, but I think this is mentioned in older planter's guides. A bit of sourness (usually combined with fruitiness) in old black teas stored very dry is usually called "winey" from a British-tea perspective. It is a sort of tasty rancidity that can be coaxed out of some teas before they go flat in the usual way. On the other hand, then you run into the "old teas" vs. "aged teas" marketing battle, where people try to offload the teas they couldn't sell fresh under the argument that they are aged and now worth just as much, if not more, using the few good examples to pull along the many bad examples.

It can also lead people to do things like buy bad black tea "for aging purposes", which seems like a bad idea.
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Baisao
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Sun Aug 14, 2022 2:29 am

mbanu wrote:
Sat Aug 13, 2022 7:39 pm
From the British-tea perspective, (at least to my understanding) all Chinese black teas are over-oxidized, as they are generally very soft and mild, but I suppose this perspective must have developed from somewhere.
On a personal note this could explain why I find British style black teas revolting yet enjoy the jam-like qualities of black teas from Yunnan, the latter having a lot of genetic similarity to the former, ergo, processing helps explains the differences between them.
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debunix
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Mon Aug 15, 2022 7:40 pm

I concur with your assessment and preference for the softer black teas.
John_B
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Tue Aug 16, 2022 3:16 am

I don't tend to notice sour range so often in black tea, but I did just write review notes for a version from Vietnam that seemed sour to me. I've long since had trouble separating out if a processing input caused related experience in the past, or if it couldn't be from atypical material being used, since I run across local plant types now and again. The same comes up with Thai sheng; if it's sour I can't know if that's a plant type input, which seems possible, or a processing flaw, maybe from leaving it too wet.

Here the idea is being discussed that sour black tea is too oxidized, as if the process needs to be stopped through a heating or drying step to offset that. That's not familiar, nor is the part about shai hong seeming sour prior to aging transition, but that doesn't mean it seems any more likely to be wrong to me. I tried another Vietnamese tea version, along with that one but from a different area, made in a style seemingly identical to dian hong. It was probably from similar material (plant type as occurs in Yunnan), so it turned out to seem like a really good example of that tea type, probably even moderately oxidized and then also sun-dried, so more or less a shai hong variation. That tea wasn't sour in the slightest. But now I am wondering if other Yunnan black tea I've tried couldn't have changed with age transition.

Black teas tasting tart seems related but different, but it really comes down to how one uses those concepts and descriptions. I really don't like tartness in black tea, but I'm not sure why it doesn't work for me. I suspect that people would only have that experience here or there, infrequently, and then tend to connect which origins relate to that aspect occurrence, when it's more just the luck of the draw that caused that, and a processing or plant type input that could as easily occur in a tea from elsewhere. I've noticed it most in Guangdong origin black teas, for example, but I doubt it's a generality or typical local style instead of a coincidence.
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