Is black tea really 100% oxidized?

Fully oxidized tea leaves for a robust cup.


Nov 9th, '10, 22:05
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Re: Is black tea really 100% oxidized?

by Sirwill » Nov 9th, '10, 22:05

Entropye... wrote:
Sirwill wrote:
Entropye... wrote:
Sirwill wrote:But wouldn't the leaves still be 100% oxidized since after the withering stage they can not be oxidized anymore physically?
If you think of it that way then green teas are 100% oxidized too.
Although, black teas are only exposed to heat after the oxidation process is complete. With green teas, it is stopped before it even starts. There isn't much of a comparison because the processes are meant to produce totally different results.
But in green tea the oxidation reaction cannot proceed anymore physically either...if it could then your green tea wouldn´t stay green very long.

The method and timing by which the oxidation reaction is stopped is different but in both cases the reaction is prevented from proceeding.
True, but again, green and black tea are two different animals.
In green tea, oxidation is stopped immediately.
In the case of black tea, oxidation is encouraged throughout the leaf. So I don't see how a green tea could be called "fully oxidized" in a literal sense seeing how oxidation is a physical process. Perhaps in a conceptual and ambiguous view, yes it could be, but I thought this discussion was literal and factual.

This kind of argument only arises with us crazy tea nerds. Hahaa :)

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Nov 10th, '10, 12:10
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Re: Is black tea really 100% oxidized?

by entropyembrace » Nov 10th, '10, 12:10

Sirwill wrote:
Entropye... wrote:
Sirwill wrote:
Entropye... wrote:
Sirwill wrote:But wouldn't the leaves still be 100% oxidized since after the withering stage they can not be oxidized anymore physically?
If you think of it that way then green teas are 100% oxidized too.
Although, black teas are only exposed to heat after the oxidation process is complete. With green teas, it is stopped before it even starts. There isn't much of a comparison because the processes are meant to produce totally different results.
But in green tea the oxidation reaction cannot proceed anymore physically either...if it could then your green tea wouldn´t stay green very long.

The method and timing by which the oxidation reaction is stopped is different but in both cases the reaction is prevented from proceeding.
True, but again, green and black tea are two different animals.
In green tea, oxidation is stopped immediately.
In the case of black tea, oxidation is encouraged throughout the leaf. So I don't see how a green tea could be called "fully oxidized" in a literal sense seeing how oxidation is a physical process. Perhaps in a conceptual and ambiguous view, yes it could be, but I thought this discussion was literal and factual.

This kind of argument only arises with us crazy tea nerds. Hahaa :)
Except you have my argument backwards...I´m saying that Darjeeling is not anymore a fully oxidized tea than green tea is because in both cases there are significant quantities of unoxidized polyphenols present. In both cases the physical process of oxidation is halted before all of the polyphenols are oxidized. The distinguishing factor is the timing and method by which this process is halted, not that the oxidation process has run to 100% consumption of the polyphenols in the black tea.

If you count 100% as the reaction cannot continue then all green and oolong teas are 100% oxidized as well. That doesn´t make sense...if you´re going to count percentage of completion it makes more sense to count the percentage of un-oxidized polyphenols present. In this case the Darjeeling black tea would not be considered 100% oxidized but then neither would green tea.

Nov 11th, '10, 15:25
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Re: Is black tea really 100% oxidized?

by Sirwill » Nov 11th, '10, 15:25

Entropye... wrote:
Sirwill wrote:
Entropye... wrote:
Sirwill wrote:
Entropye... wrote:
Sirwill wrote:But wouldn't the leaves still be 100% oxidized since after the withering stage they can not be oxidized anymore physically?
If you think of it that way then green teas are 100% oxidized too.
Although, black teas are only exposed to heat after the oxidation process is complete. With green teas, it is stopped before it even starts. There isn't much of a comparison because the processes are meant to produce totally different results.
But in green tea the oxidation reaction cannot proceed anymore physically either...if it could then your green tea wouldn´t stay green very long.

The method and timing by which the oxidation reaction is stopped is different but in both cases the reaction is prevented from proceeding.
True, but again, green and black tea are two different animals.
In green tea, oxidation is stopped immediately.
In the case of black tea, oxidation is encouraged throughout the leaf. So I don't see how a green tea could be called "fully oxidized" in a literal sense seeing how oxidation is a physical process. Perhaps in a conceptual and ambiguous view, yes it could be, but I thought this discussion was literal and factual.

This kind of argument only arises with us crazy tea nerds. Hahaa :)
Except you have my argument backwards...I´m saying that Darjeeling is not anymore a fully oxidized tea than green tea is because in both cases there are significant quantities of unoxidized polyphenols present. In both cases the physical process of oxidation is halted before all of the polyphenols are oxidized. The distinguishing factor is the timing and method by which this process is halted, not that the oxidation process has run to 100% consumption of the polyphenols in the black tea.

If you count 100% as the reaction cannot continue then all green and oolong teas are 100% oxidized as well. That doesn´t make sense...if you´re going to count percentage of completion it makes more sense to count the percentage of un-oxidized polyphenols present. In this case the Darjeeling black tea would not be considered 100% oxidized but then neither would green tea.
Fair enough and your argument is understood!

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Nov 12th, '10, 09:31
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Re: Is black tea really 100% oxidized?

by Tead Off » Nov 12th, '10, 09:31

I am not an expert on Darjeeling teas but can report on what I see visually. Many of the better teas, or, what we are told are the better Darjeelings, are not nearly 100% oxidized. In fact, many are not black at all, and am told the color is also a result of how high fired the tea is in the drying stage. The higher the heat (air dryed in Darjeeling, not roasted), the darker the teas look. I was told the temperature of the air plays a significant role in the taste. But, these things can be better explained by one of the Darjeeling tea sellers like Rajiv from Tea Emporium. Maybe he will chime in to this conversation. I was certainly not going to understand all the ins and outs of Darjeeling tea from a 1 week visit. In fact, it is damned confusing as there is a myriad of teas being sold there and different invoice #'s of the same tea will mean different tasting tea. This is a case of really trusting your vendor. :lol:

Nov 12th, '10, 10:45
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Contact: brose

Re: Is black tea really 100% oxidized?

by brose » Nov 12th, '10, 10:45

100% oxidized implies that the tea is all CO2, NOx, POx, etc. gases as well as fully oxidized metals.
I assume the way the way this topic is going that what is actually meant is that 100% of the polyphenols are oxidized.

Nov 12th, '10, 13:28
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Re: Is black tea really 100% oxidized?

by Sirwill » Nov 12th, '10, 13:28

brose wrote:100% oxidized implies that the tea is all CO2, NOx, POx, etc. gases as well as fully oxidized metals.
I assume the way the way this topic is going that what is actually meant is that 100% of the polyphenols are oxidized.
Correct.
Although, it is impossible for every polyphenol in the leaf to oxidize unless you ground it into a very fine powder of sorts haha.
So while black teas are classified as "fully oxidized," there is really no such thing as far as percentages go.

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