Worcester daily spy. [volume] (Worcester [Mass.]) 1850-1888, 1871-09-14
The Manufacture of Black Tea.


| Probably one of the most curious and inter-
| esting features connected with the tea mAnufac-
ture in China, is the fact that the newly plueked
leaves apparently possess neither that aromatic
bttcr and astrngent taste, nor the fragrant odor
Characteristic of the finished articles these Valll-
able idosynCrascs being evidently developed,
or at least rendered prominent, during the pro-
cess of manipulation. Another notable point is
that different qualities may be prepared from
the same plucking or harvest CT leaves, which,
by varied treatment can be converted at pleas
ure into black, sem-iermented, or green tea. IL
is by a heightened exposure Of the leaves TO the
air and sun. accompanied by fermentation and
gradual roasting and firing that the d'stin-
gushing color and favor are developed in black
tea; quick scorching iand rolling without fer.
mentation or exposure, but with the addition OF
more or less colOring pigment, producing the
desired appearance of green; while some expos
ure in the open air or in the whitening chamber
Yields the varieties known as Oolong PouchOng,
&C., and in India as Namunna teas. The rea-
son of this becomes obvious when the chemistry
Of the operations is considered. According to
DR.. Stenhouse, the tannin OF tea leaves is asso.
ciated with small quantity of gallo acid
afording a blue black precipitated with iron
salts. Teaeaf tannin being glucoside, when
united with ferric salt and applied to animal
| membrane, eXerts similar influence to oak
bark in producing leather; and, in COM
mon with other tannins it exhibits
remarkable thirst for oxygen, especially
in presence of metallic base. Now, expert
ence has taught the Chinese that the presence
or absence of iron absorbed from the soil and
imprisoned in the tissues of the tea plant is a
matter Of so much importance in influencing
their decision as to whether the crop shall be
converted into black or green tea, that de-
parture from the rule, at first founded on OBJ
servation and latterly confirmed by chemical
research, Is never attended with good results
Thus, although portion of the same harvest,
when dried and roasted quickly, produces a
green tea, and when subjected to protracted eX-
posture, fermentation and manipulation, black
tea, superiority as to quality in either cannot be
attained unless the preparation be judiciously
modified or reversed in view Of the presence or
absence of iron in the leaves. In other words,
where the soil is destitute of or deficient in fer
ric salts, the leaves produced are made into
| green tea; where iron abounds, the Chinese
manufacture black tea. Accordingly, travellers
mention it as prominent feature OF the Mon
ing or black tea districts that chalybeate springs
| are plentiful, and the highly ferrugnouS nature
Of even the surface soil indicates an excess of
iron not usually met with in those localities de-
| voted to green tea. Where this popularity is
| less evident, as in the plantations around Foo.
chow, 1t is found that their produce is so modi-
fed in color by the smaller amount of iron pres
ent as to have earned for it the distinctive name
of "red leaf tea." In India the same ierrugin-
GUS element must be coaXed into usefulness
when present, and in its absence a modified for
mula adopted; hence 1t ls on account of the
paucity of iron in the soil that 1t has been re-
commended always to convert the produce of
Kangra, 1ukvar, Kurisong, Dchra Dhoon, and
some parts Of Darieeling, into green tea.
The distinguishing process through Which
black tea passes, but from which green tea is
exempt, is fermentation, which produces
marked changes in the constituents of the
leaves. When the process is overdone, so that
portion Of the tannin is converted into free
gallo acid, the tea is found to have acquired a
more or less sour flavor, and in consequence its
worth Is materially deprecated. To the yaluer
or dealer possessed Of fine taste and keen sense
of smell, there is no flavor more Objectionable
than this; accordingly, samples which exhibit
slight acidity, or even a tendency in that direc-
ton, are unhestatingy priced at from four
pence to six pence per pound less than would
otherwise be the case, although they may rep
resent most attractive teas in every other re-
spcCt In order to prevent all risk of sourness
(Which was an unfortunate characteristic of the
tea produced in some Indian gardens until with
in the last few years., it has been recklessly
suggested that fermentation should be wholly
abandoned. But this rash proposal, if ever
seriously entertained, could only be adopted at
the sacrifice Of that delicious fragrance and
grateful aroma which distinguish China tea, and
in which most Indian growths are lamcntably
deficient