211 
September i, 1890.] THE TROPICAL AGRICULTURIST. 
contains (besides the common plant-constitueEts) 
theine, a volatile oil, and tannin. Theine is a rank 
poison, in toxic doses causing convulsions and paia- 
iysis, in lethi doseea death ; but in snaall quantities 
is (like strychnine) a delicate tonic. Of the volatile 
oil, Y. Kozai can affirm little beyond its well-known 
exciting action upon the organs of taste and smell ; 
nor is it easy to follow it analytically through the 
proct S'?es of manufacture ; the hot steaming employed 
(at near boiling temperature) in the green-tea manu- 
facture does not appear to diminish the volatile oil 
sensibly, though Y. Kozai intimates that preparing 
green tea by bciliog does dissipate the aroma. As to 
the properties of tannin, it is an astringent remarkable 
for its strong affinity for the albuminoids ; hence, if 
taken in excess,it may, by preeipititing the ferments 
of the digestive fluids, cause im igestion. 
The account of the chief Japanese methods of manu- 
facture is of more interest and instruction to the Euro- 
pean planter. 
We may premise that there are two (main) kinds 
of tea, viz. black and green. In the manufacture of 
black tea there are four essential processes, viz. (1) 
withering; (2) rolling, (3) fermenting, (4) drying. 
In the manufacture of green tea, the fermenting is 
omitted, and in Japan (for some kinds of green) the 
rolling also. 
For the manufacture of black tea there is no real 
difference between the Japanese method and that 
practised by English planters in Bengal. The fresh 
picked leaf (i.e. tips of the young shoots) must be first 
withered, or the petioles and leaves break under the 
rolling ; the exposure of an hour or two in strong 
sun withers tfle leaf sufficiently ; if there is no sun, the 
leaf must be withered by the aid of fire-heat. The 
rolling is done, even in Japan, by the aid usually of a 
box, and in Bengal often by steampower (and very 
roughly). The juices are thus expressed, and the leaf 
given a “ nice” twist, i.e. a twist pleasing to the fancy 
of the tea purchaser. What perhaps renders rolling 
so essential in the manufacmre of black tea (for it is 
not essential in the manufii ture of green), is that it 
masses the leaf in a state conducing without delay to 
fermenta'ion. Neither Y. Kozai nor the best Bo- gal 
authorities like to lo=e the juices more than can be 
helped. He also hazards the view that, by rolling, 
the juice is expressed from the cellular tissues of the 
leaves an! impregi-ated upon their surface; thus is 
produced fine aroma, and the leaves are more easily 
infused. Fermentation is the most important point 
in the manufacture of black tea, and by it {fide Y. 
Kozai) the leaves lose their raw smell, and tho tea 
acquires its fine flavour. The fermentation is really 
only carried a very little way: Y. Kozai says it should- 
be allowed, in a temperature of 104° F., to proceed 
only for about an hour. He thinks the process is a 
true fermentation, because if permitted to run too far 
the tea acquires an acid taste. He thinks it probable 
that the ferment is caused by a living organism, but 
he adduces very slight ground for this opinion ; and 
it has, in fact, been questioned whether there is .any 
true fermentation in the process at all. But the 
Flnglish tea-makers are agreed with the Japanese in 
the importance of stopping the fermentation exactly at 
the proper point by drying the tea, which is usually 
done by placing it first in the suii and turning it 
over till it is fairly dry, and then thoroughly drying 
it by fire-heat. 
The residt of all the Bengal experience is that the 
black tea is at least as good when these four processes 
are done simply and rapidly, as when much labour and 
time are expended in complicating them. In the early 
days of tea manufacture by Anglo-Indians, great pains 
were taken to imitate with tedious minuteness the 
careful h.and-proccsses (and repetitions of portions of 
the processes) as practised in China ; but all planters 
now follow rapid short cuts to tho finished tc.a. 
The manufacture of green tea is nothing more than 
drying the leaf; it is so little practised in British 
India as to be of no commercial interest there, but 
y. Kozai describes in detail three kinds of green tea 
manufactured in Japan. 
(1) Japanese (not China) yreeg tea, In this, the leaf 
is steamed in order to remove the raw flavour; it 
is then rolled and fire-dried, the two last processes 
being usually done together. 
(2) Chinese green tea. In this, the leaf is roasted 
(while stirred with a stick) in an iron pan over a 
fire, then rolled a little, then roasted again; these 
processess being repeated even six or eight timts, and 
the tea is then finally dried off. 
(3) Flat tea, the highest class tea of all. For this 
tea, the shrubs are usually kept shaded for three 
weeks before picking, so that the leaf is partly etio- 
lated. The choicest leaves are selected before the 
manufacture is commenced. They are steamed, but 
never rolled; nor, indeed, touched by hand at all. 
but carefully turned by the aid of a bamboo stick. 
Alter sufficient steaming they are simply dried. 
The au hor finds by analysis that there is 30 per 
cent, more theine in etiolated leaves than in the leaves 
of the same plants grown in the light. Ha tried 
many experiments to test the chemical effect of the 
manufacturing processes. Among other tables given 
by him is the following ; a quantity of leaf was 
divided into three portions, whereof one portion is 
A, another portion is manufactured into green tea 
B, the third portion is manufactured into black tea 
0. Y. Kozai analyzses A, B, C, and finds — 
A. 
B. 
C. 
Crude protein 
37-33 
37-43 
38-90 
Crude fibre 
10-44 
10-06 
10-07 
B hereal extract 
6-49 
553 
5-82 
Other nitrogen-free extract 
27-86 
31 43 
35-39 
Ash 
4-97 
493 
4 93 
Theine 
3-30 
3-20 
3-30 
Tannin 
12-91 
10 64 
4-89 
He remarks that the general result of the green- 
tea manufacture is merely to dry the leaf ; the black- 
tea manufacture alters materially its chemical consti- 
tution. The principal change is the remarkable dimi- 
nution of the tannin. He does not explain how this 
is brought about, nor is it easy to see how the in- 
cipient fermentation should affect the tannin. 
The only teas exported t-i E n'ope from Japan are 
of low class ; they are frequently “ faced,” and some- 
times mixed with the leaves of various Japanese plants. 
Any plentiful leaf, not too unlike the. leaf of tea, will 
do for this adulteration ; the L aves actually employed 
are (Y. Kozai assures us) all harmless, aud several 
contain tannin, but none of them any theine. As to 
the “ facing,” he says it can hardly be called adul- 
teration ; the quantity of Prussian blue employed to 
improve the appearance of green tea is (according 
to Y. Kozai) about 0 001 per cent, the weight of the 
tea, perfectly innocent, and pleasing to a purchaser. 
The author concludes with an account of the dif- 
ferent ways of taking tea in Japan, with some ana- 
lyses of the prepared liquor. 
(1) In the case of flat tea, or of the very finest 
quality of Japanese green tea, the tea is ground to 
line powder, and the whole infusion drunk. 
12) In the case of superior {i.e. from the Japan 
point of view) tea, the leaves are infused for two 
minutes in water at 120°-150° F. 
(3) In the case of a medium tea, the leaves ate 
infused for one minute in boiling water. 
(4) In the case of inferior tea, the leaves are 
boiled in water. 
The object to be aimed at in the preparation is to 
get the largest possible quantity of theine without 
dissipating the aroma, and accompanied by only a 
moderate amount of tannin. Y. Kozai gives analyse.s 
to show that this is effected (in the case of superior 
teas) by the infusion in water at 120°-150° F. for 
two to five minutes. By superior teas, he understands 
teas worth five to seven shilliugs a pound in Japan. 
It is probable, therefore, that the highest class teas 
we ever have to deal with in England come under 
the medium teas of Y. Kozai, which require infusion 
in boiling water — for one minute at least. The 
majority of English people like a good deal of chicory 
with their coffee, and probably a majority also like 
a good deal of tanqin with their te.i; ani to theci 
