On Aug 22, 2:20 am, cha bing yahoo.com> wrote:

Both interesting and thought provoking.

The threshold reaction to Bitter taste appears to be much lower in the
USA than Europe. Robust CTC teas are the most popular in Britain but
the lighter more mellow orthodox teas are preferred in the USA. An
English Breakfast tea is principally blended from East African CTC
teas that we with enthusiasm would say are pungent and astringent but
are disliked in the New World as being too bitter. Sweet tea so
popular in the US south, and tea bag tea generally, based on almost
tasteless non bitter South American orthodox teas, is anathema to most
of us over here. The cultural acceptance in the USA of black teas
brewed in below boiling water I believe is due to this method
resulting in a less bitter liquor. With the exception of the
excellent micro brewery beers I suspect that American commercial beers
(Lites!) have the same lack of bitterness compared to European
preferred brews - the standard beer of Britain is even ordered as "a
pint of Bitter ".

However, bitterness in tea derives from different sources than in
coffee. Coffee is roasted at a much higher temperature than is any
tea. Product temperature (in the bean) will reach well above 200
degrees C when pyrolysis occurs - a heat producing (exothermic)
reaction breaking down carbon to CO2 that actually supplies 12%% of the
energy required for the roasting. (Financially hard pressed tea
producers should be so lucky!) The pyrolysis products give the
typical brown color and roasted coffee aroma (nobody would choose to
drink coffee made from green coffee beans), but pyrolysis also
produces some very bitter compounds - and the higher the roast the
more there is of them. Normal teas are dried at the much lower
temperature of 95-105 degrees C and while some browning (and flavor
production) occurs in oxidised teas when sugars and amino acids react
(by heat induced Maillard reaction - similar to browning of roasting
meat) this in tea occurs sub 100 degrees C. The only teas dried much
above 100 deg C are the so called roasted ones - mainly some oolongs
and greens. Traditionally this is done in a charcoal fired wok and,
while the temperature of the wok surface is definitely very hot (I
have seen 160 deg C quoted) the actual leaf temperature is less than
this as it is constantly stirred and moved away from the hot metal.
As the leaf dries the temperature is reduced but is nevertheless is
hot enough to produce the roasted flavor - in those tea types where it
is required. In black tea too high a temperature is bad - called by
the tea maker "high firing" or "bakey" if only a touch high - and is a
character required in some teas - Darjeelings are typically high
fired. If too high it's termed "burnt" and value drops like a stone.
Chosen Oolongs are allowed the high fired character when it is called
"roasted" - but it does not I think impart any bitterness.

Nigel at Teacraft