Improvements in the Preparation of Tea.
Year: 1892

page_text: Date of Application, 29th Apr., 1892
Complete Specification Left. 26th Jan., 1893-Accepted, 11th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in the Preparation of Tea.
I, DAVID JAMES PLAYFAIR, of 12, Woodside Terrace, Glasgow, in the
County of Lauark, North Britain, Manufacturing Chemist, do hereby declare the
nature of this invention to be as follows, that is to say :-
My said invention has for its object the preparation of tea in a manner to render
the infusion or water extract thereof free from the whole or a large portion of the
tannin or astringent matter which is a natural constituent of the tea.
In carrying out my invention I employ gelatin to form with more or less of the
tannin of the tea a compound which is not soluble in the water used for infusion.
I prefer to operate so that the said compound may be formed before the infusion is
made, because if formed at the time of making the infusion, the infusion will be
turbid instead of being clear.
In proceeding according to one modification I take the dry leaf tea of commerce
and moisten it with warm water, and I add a warm solution of pure gelatin. I
then thoroughly mix the whole until of uniform appearance and subsequently
remove the water by the application of heat or by means of a current of dry
warm air.
Instead of first moistening the tea as described I may at once mix it with a
solution of gelatin, subsequently drying as before.
Or in the original manufacture of the tea from the green leaf a solution of
gelatin may be applied at any convenient stage of the processes.
In practice I prefer to use somewhat less gelatin than what is required to
combine with the whole of the tannin present in the tea in order to avoid the
presence of gelatin in the infusion. The quantity of gelatin required varies with
the character and quality of the tea but for an ordinary Indian tea from 7 to 12 per
cent. of gelatin may be used. .
When tea has been prepared in the manner herein before described the infusion
of it as made in common domestic use, will be free from all or a large portion of
the tannin or astringent matter ordinarily present, and the beverage will be more
palatable and less injurious.
Dated this Twenty-eighth day of April 1892.
EDMUND HUNT,
Per pro David Ferguson,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in the Preparation of Tea.
I, DAVID JAMES PLAYFAIR, of 12 Woodside Terrace, Glasgow, in the
County of Lanark, North Britain, Manufacturing Chemist, do hereby declare
the nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement, that is
to say :-
My said invention has for its object the preparation of tea in a manner to render
the infusion or water extract thereof free from the whole or a large portion of the
tannin or astringent matter which is a natural constituent of the tea.
In carrying out my invention 1 employ gelatin to form with more or less of the
tannin or astringent matter of the tea a compound which is not soluble in the water
used for infusion. I operate so that the said insoluble compound may be formed
[Price 8d.]

page_text: before the infusion is made, because if formed at the time of making the infusion,
the infusion will be turbid instead of being clear.
In proceeding according to one modification, I take the dry leaf tea of commerce
and inoisten it with warm water, and I add a warm solution of pure gelatin. I
then thoroughly mix the whole until of uniform appearance, and subsequently
remove the water by the application of heat or by means of a current of dry
warm air.
Instead of first moistening the leaf tea as described I may at once mix it with a
solution of gelatin, subsequently drying as before.
The proper quantity of gelatin for any particular batch of leaf tea may be
ascertained by making an infusion of a small quantity of the batch of tea and
titrating the infusion with a solution of gelatin containing a known proportion of
gelatin, until turbidity ceases to be produced. The quantity of gelatin required to
act on the whole of the tannin or astringent matter of the entire batch will be in
proportion to that used in the titration; I however prefer to use somewhat less
gelatin than that required for combining with all the tannin or astringent matter,
in order to avoid the presence of gelatin in any subsequently made infusion.
The quantity of gelatin required varies with the character and quality of the tea,
but for an ordinary Indian tea 7 to 12 per cent. of gelatin may be used.
In order to obtain the best results it is important to use sufficient water to
insure the penetration of the gelatin into the substance of the tea leaf instead of,
to a greater or less extent, forming a coating, otherwise the gelatin and tannin or
astringent matter will not be completely combined and an infusion subsequently
made will be turbid. I find that gallons of water is a suitable quantity for
10 pounds of leaf tea. In the modification in which the leaf tea is first moistened,
gallon of water may be used for that purpose, the subsequently added solution of
gelatin being formed with 1 gallon; and in the modification in which the gelatin
solution is added without previously moistening the leaf tea the solution should be
formed with 1 gallons of water.
In the original manufacture of the tea from the green leaf a solution of gelatin
may be applied at any convenient stage of the processes.
When tea has been prepared in the manner herein before described, the infusion
of it as made for common domestic use, will be free from all or a large proportion
of the tannin or astringent matter ordinarily present, and the beverage will be more
palatable and less injurious.
The removal of the tannin or astringent matter promotes the solubility of the
theine, which in ordinary tea is combined with the tannin forming a compound
which precipitates on the tea infusion cooling. In an infusion made from the
prepared tea there is little or no precipitation on cooling. With the prepared tea
no harm is done by "over-drawing or long continuance of the infusing process,
whereas with ordinary tea such over-drawing increases the quantity of tannin
extracted.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I, declare that what I
claim is:
Preparing tea by rendering its tannia or astringent constituent insoluble in the
leaf by means of a solution of gelatin, substantially in the manner and for the
purposes herein before described.
Dated this Twenty fifth dan of 1000
EDMUND HUNT,
Applicant's Agent.