> Table 1 for example 150.32 milligrams per gram is shown for catechins
> in the Bud & 1 Leaf in percentage terms this is only 15% catechin -
> low even for a Japanese clone (Yabukita 19.8% and Benihomare 25.6% -
> according to Nakagawa, and for a black tea clone's Bud & 1 Leaf shoot
> try 35% catechins - Nant). In Table 2 Column 2 should be headed
> Soluble Solids not Solubility, though these figures are suspiciously
> high showing 37.91% for 6th leaf even if it were a 6 leaf and bud
> shoot rather than just the 6th leaf as indicated. In Turkey the
> soluble solids for a 6 leaf shoot would struggle to get above 29%.
> Polyphenols are OK as shown but the Catechins cannot be higher than
> the total Polyphenols. And 76.3% catechins in the 3rd leaf would be a
> biochemical anomoly and a bitter cup indeed!!
>
> Nigel at Teacraft

I know I have to do extra work when Nigel (or Dogma) is involved

First, just to mention that the article is designed for an average tea
drinkers with zero knowledge of green tea, and the point to illustrate
is that younger tea shoots contain more catechins and theanine.
Anything more I add to the article would simply confuse my audience.

Now back to Nigel ...

The figures I quoted are typical of Chinese literature, where
polyphenol is around 30% and catechins below 20%. I don't think they
look unreasonable.

The 15% catechins content is for fresh leaf, which in percentage term
will be lower compared to dried tea extract. Harold Graham in his
paper Green Tea composition (1992) quoted a range of 16% to 30% for
fresh tea leaves, and 30% tp 40% for extract solids. So yes, the
catechins look low, but is still within a reasonable range.

Are your figures for fresh leaves or dried tea extract?

The second table is open for interpretation. I've left it as it's
because it illustrates the point that younger tea shoots contain more
catechins than the older ones. It appears to me that the 76.3% is as a
percentage of something, maybe the polyphenol, but I am not sure.
It'll tie in as catechins consist about 70% of polyphenol, although
the reduction seems quite rapid with age.



Now to Lewis...

<I'm not so sure about this argument. It's hardly unusual for
<black/red tea to be made from young shoots. And the main reason
<oolong is made from mature leaves, I think, is that they hold up
<better under the kneading and rolling during manufacture.

Generally speaking, high grade green tea is made from a single bud up
to two adjacent leaves. Whereas oolong tea or red tea is made from the
2 to 4 leaves. There are exceptions, like the famous green tea Liu an
Gua Pian.

Processing is important. But the chemical difference between the two
is important too.

Julian
http://www.amazing-green-tea.com