The tedious, long-drawn-out details of tea manufacture, of the
repeated, meaningless, tossing back and forth and Chinese
juggling with the abused tea leaves, are but too familiar to
students of the subject: and too disappointing also, when we are
moved to ask--Why all this manipulation? What is the nature of
the chemical changes which take place?
So far as we can ascertain by diligent inquiry and reading, no
competent authority has answered these questions satisfactorily.
We have been deluged with generalities and opinions which
contradict themselves, but when we search for a categorical
answer to a simple question, experts hide under a shower of
meaningless phrases. We, alas, are not an expert, nor a chemist,
but just a simple enquirer in search of knowledge expressed in
plain English. Therefore be patient dear reader with our
endeavors to represent or interpret existing conditions of expert
knowledge of tea manufacture at this time. Peradventure a feeble
ray of light may illuminate the darkness of the subject.
Corrections and additions will be welcomed in our future editions
and credit given to their authors.
Teas may conveniently be divided into the three classes which
have so long been recognized by the American tea trade, namely:
Green teas, the first remove from the green leaf.
Oolongs, delicate Black teas, having properties further developed
than those of Green teas.
Souchongs, and Congous, both of which have been called "English
Breakfast" teas by Americans, because the former teas were the
customary breakfast beverages of the English people before the
advent of Indian teas.
In these latter teas, fermentation and firing are prolonged beyond
the treatment of Oolongs. The smoky flavor sometimes apparent is
owing to careless and extreme firing.
In making Green tea, the object seems to be to expel the watery
juices of the leaf and to cure or dry it with the least delay.
Hence, the leaves are not exposed to the sun, but are first dried
in the air for a short time. They are next exposed to artificial
heat, which renders them flaccid and pliable, and prepares them
for the third operation of rolling, which twists the yielding
leaf as seen in manufactured tea, rolls it up into balls, and
squeezes out a considerable portion of its watery juices. It is a
singular fact that in the Chinese methods, they endeavor to get
rid of the exuding juices, while in the Indian treatment,
according to Mr. crole, the manufacturing expert, effort is made
to preserve the sappy juice, and it is continually taken up again
by the balls of leaves. The balls are now broken apart, and the
scattered leaves are submitted to the final drying process by
fire, which finishes Green tea. In this case, it is plainly the
heating treatment which develops the faint flavor and odor of
Green tea, for no fermentation is allowed to begin, unless indeed
brief and unobserved action takes place within the compressed
In making an Oolong Black tea, which occupies an intermediate
position between Green tea and Black Souchongs and Congous, the
leaves are first exposed to the action of the air for a
considerable time, and in many cases, to the sun also. An
incipient fermentation may take place, although this is denied by
some. There is certainly a chemical change beyond the brief
preliminary drying of Green tea. During this period the leaves
(in China) are stirred and tossed by the hands. The effect, if
not the object, is to expose greater surfaces to the air, and to
increase oxidation. It is during this operation that the leaves
first begin to manifest characteristics of manufactured tea, in
the way of a fragrant tea odor which the green leaf did not
possess. The development of sweet odors in new hay, quite
different from those of green grass, and also the artificial
development of flavor in tobacco leaves, may be recalled in this
connection. This prolonged exposure to the air is termed
"withering," and the leaves become soft and flaccid, as they do
in the first artificial heating for Green tea. In withering, the
leaves lose about one quarter of their weight in moisture. The
leaves must not be bruised before the termination of this
treatment, or injurious chemical changes will begin.
The second operation with Black tea is the same rolling into
balls, twisting and squeezing, as in Green tea. Mr. Crole says
that the sap of the leaf thus liberated from its cells "is
spread all over the surface of the rolled leaf, where it is in a
very favorable position for the oxygen of the atmosphere to act
upon it during the next stage of manufacture, namely,
fermentation." Fermentation, he regards as an oxidation process
For the "fermentation" stage, if that controverted term correctly
designates the process, the rolls are either left undisturbed to
heat, or, as in Indian methods, the rolls are broken up, and the
leaves distributed in drawers, with free access of air. In either
case, a spontaneous heating follows, and chemical action is
indicated by a change of color which reddens and darkens the
leaf, and by the evolution of further pleasant "tea" odors. Some
of the tannin is said to be converted into glucose.
Care must be taken, Mr. Crole says, to arrest fermentation at the
proper stage by the first "firing," and this firing expels about
half of the remaining moisture of the withered leaves, and
probably develops an additional portion of those volatile oils
which give fragrance and taste to manufactured tea; and which Mr.
Crole designates by the name of "theol." Too high or too long
continued firing drives off these oils with the watery juices.
They are also wasted by exposure of manufactured tea to the
atmosphere. Firing is sometimes divided into two or three stages.
In the above summary we have described all essential treatment of
tea leaves necessary to produce manufactured tea.
To procure the extreme type of Black teas, a Souchong or Congou,
the fermentation or oxidation, and the "cooking" process, is
simply carried further, and with higher roasting, some of the
volatile oils and delicate flavors are expelled, or are changed
into other flavors. Judging by diminished effects upon tea
drinkers, some of the volatile theine is also lost.
Both in China and Japan it is the custom to give large portions
of the tea crop which are intended for export to foreign
countries, only a preliminary drying or curing sufficient to
preserve them temporarily. When they arrive at the shipping ports
they are subjected to additional firing and thorough drying.