IMPROVEMENTS IN THE CLARIFICATION AND PRESERVATION OF CERTAIN VEGETABLE INFUSIONS OR DECOCTIONS"
Year: 1882

page_text: LETTERS PATENT to Samuel Cleland Davidson of Belfast in the County of
Antrim, Ireland, Merchant for an Invention of "IMPROVEMENTS IN THE
CLARIFICATION AND PRESERVATION OF CERTAIN VEGETABLE INFUSIONS OR
DECOCTIONS"
PROVISIONAL SPECIFICATION left by the said Samuel Cleland Davidson
at the Office of the Commissioners of Patents on the 3rd February 1882.
SAMUEL CLELAND DAVIDSON of Belfast in the County of Antrim, Ireland
Merchant " IMPROVEMENTS IN THE CLARIFICATION AND PRESERVATION
CERTAIN VEGETABLE INFUSIONS OR DECOCTIONS
"
OF
The improvements relate to the clarification and preservation of aqueous infusions
or decoctions of tea, coffee, cocoa and ginger. The infusions or decoctions when
clarified and preserved as hereinafter described may be made use of as extracts or
essences, either for mixing with cold or hot water or for mixing with water
charged with carbonic acid gas under pressure in bottles to form effervescing or
sparkling beverages. They yield liquors which keep good an indefinite period and
have a bright attractive appearance with much of the color and nearly all the
characteristic flavour and aroma of the original infusions.
In the first place an aqueous infusion or decoction of the tea, coffee, cocoa or
ginger is prepared with boiling water, or water of any less temperature that will
produce an infusion of desirable strength and quality and preferably of about
treble or quadruple the strength at which such infusions are ordinarily used as
beverages. Ten to 15 minutes usually suffices for extraction of the infusions,
after which the leaves or grounds should be completely removed. The infusions
should then be cooled as quickly as possible and when at about 60° Fahrenlicit
they usually have a dull, muddy or turbid appearance, and more particularly so
with the tea infusions when the tea used is of superior quality.
My improvements in the clarification and preservation of these or such like
infusions or decoctions are as follows:-
I add thereto and stir into same a sinall quantity of an aqueous solution of
tannic acid, prepared by boiling tannic acid in water till the peculiar smell which
Price A1

page_text: usually accompanies tannic acid is sufficiently driven off to be scarcely if at all
noticeable in the solution when cold, and the solution should be employed cold or
nearly so. This solution of tannic acid is to be added until by its action a
flocculent precipitation is produced in the infusions.
After stirring this in for a short time the precipitate should separate from the
mother liquor, leaving it fairly transparent. I then preferably at this stage, add and
stir in an amount of silicylic acid equal to about 11 or 2 per cent. more or less of the
weight of the dry tea, coffee, cocoa or ginger used in making the infusion, and silicylic
acid being of a difficultly soluble nature in cold liquors of this sort, I preferably add it
dissolved in a hot aqueous solution stirring it into the liquor vigorously while being
added. The infusion is then to be further stirred for about a quarter of an hour,
the temperature being retained at 60° Fahrenheit or thereabouts and then the liquor
should be decanted off or filtered free from the precipitated matter as this matter
would otherwise soon enter into a state of change or decomposition harmful to the
liquors and the ordinary bag filter of close well woven cotton cloth is a suitable
and convenient form of filter to use. On pouring the infusions into the bags the
first of the liquor that passes through is usually not quite bright and should be
returned to the filter, but if the treatment with tannic acid has been sufficiently
complete the liquor soon runs bright.
The filtered liquor should then be set aside in a place where a temperature of
about 60° Fahrenheit will not be exceeded, and a few degrees lower is preferable,
and in about 24 hours afterwards it should be examined, and usually it will then
be found to have again become more or less dull and turbid according to the
nature of the liquors, and to the quality and description of the material from which
the infusions were made. This turbid or clouding matter is usually so exceedingly
fine that it would be very difficult to remove by any ordinary filtration; and to
effectually collect and remove it, I then treat the liquors with an aqueous solution
of gelatine, containing an amount of gelatine which in its dry state would-be equal
more or less to about 1 to 2 per cent. of the weight of the dry tea, coffee, cocoa
or ginger employed in making the infusions. This solution of gelatine I preferably
use of a strength equal to about 3 or 4 grains of gelatine to the ounce of water and
preferably employ it at a luke warm temperature. On stirring this into the
infusion a flocculent precipitate will immediately form up, gathering with the
precipitate already formed in the liquor and the infusion should then be stirred
gently and continuously for about a quarter of an hour and then poured into the
filter bags and filtered free from this precipitated matter. The resulting liquor
will be pure and bright and will show no tendency to further clouding or dulling
on being kept. The employment of gelatine at this stage is further beneficial to
the liquor by combining with and removing therefrom part of the excess of the
tannic acid previously added, but a slight excess of tannic acid should still remain
in the liquor to ensure that all the gelatine has been precipitated and as a test of
this the finished liquor should still be capable of precipitating a small amount of
gelatine if added. After this last filtration it is advisable to add a further amount
of salicylic acid equal to from an eighth to a quarter of the amount already added,
and the liquors are then finished and ready to be used as essences for mixture with
ordinary water hot or cold and if diluted to a suitable degree with cold water they
may be bottled like wines and used similarly, or they may be bottled in combi-
nation with water charged with carbonic acid gas under pressure to form
effervescing and sparkling beverages. In the preparation of these clarified infusions
it is preferable to use water containing sulphate of lime in solution, or if the water
be naturally deficient in this particular it should be artificially "hardened" by
adding powdered gypsum to it before the infusions are taken. If the infusions
are required sweet it is preferable to add the sugar to the water before making
the infusion though it may if desired be added to the hot infusion immediately
after separation of the leaves or grounds, or at any other convenient time during
the preparation of the liquors, but the former usually gives the most desirable
results. The addition of the first application of silicylic acid way optionally

page_text: be made before the tannic acid treatment, or it may be deferred till after the first
filtration, but the preferable time for its application is shortly after the tannic acid
treatment as first described.
With some particular growths of tea which are exceptionally rich in native
tannic acid, it is possible to obtain from their infusions a clarified liquor by
treating same with gelatine solution alone and a flocculent precipitate will be
obtained therewith, which will filter out from the mother liquor without any
treatment with the artificially prepared tannic acid but such liquors will still
contain in solution matter which if allowed to remain would be deleterious to their
keeping qualities, for although in this condition they might be preserved from
absolute decay by a copious application of salicylic acid, yet the flavour of the
liquors would gradually undergo alteration in consequence of the non removal of
this matter and as the precipitation and removal of this matter can only be.
effectually accomplished by the tannic acid treatment this treatment even with
such infusions is therefore a necessity and cannot be omitted although the infusions
may be rendered transparent and bright looking without it.
After the last and final filtration care should be taken to prevent dust or other
impurities getting into the liquors, as all such have a harmful effect.
In the preparation of the tannic acid solution I find it desirable to employ water
that is naturally "hard" or which has been artificially hardened by the addition of
gypsum, and I further find it desirable to add to the boiling water and along with
the tannic acid an amount of sugar equal to about double the weight of the dry
tannic acid used.
For the successful carrying out of these improvements it is of importance that
the material used in making the infusions should be in fresh and good condition
and entirely free from even an incipient approach to decay from any cause and as
there are many different growths and qualities of tea, coffee and cocoa, experience
and taste will guide the selection and blending of the same so as to obtain the most
desirable liquors and flavours.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Samuel Cleland Davidson in the Great Seal Patent Office on the
2nd August 1882.
SAMUEL CLELAND DAVIDSON of Belfast in the County of Antrim, Ireland,
Merchant "IMPROVEMENTS IN THE CLARIFICATION AND PRESERVATION OF
CERTAIN VEGETABLE INFUSIONS OR DECOCTIONS"
The improvements relate to the clarification and preservation of aqueous
infusions or decoctions of tea, coffee, cocoa and ginger. The infusions or decoctions
when clarified and preserved as hereinafter described may be made use of as
extracts or essences either for mixing with cold or hot water or for mixing
with water charged with carbonic acid gas under pressure in bottles to form
effervescing or sparkling beverages. They yield liquors which keep good an
indefinite period and have a bright attractive appearance with much of the color
and nearly all the characteristic flavour and aroma of the original infusions.
In the first place an aqueous infusion or decoction of the tea, coffee cocoa or ginger
is prepared with boiling water, or water of any less temperature that will produce
an infusion of desirable strength and quality and preferably of about treble or
quadruple the strength at which such infusions are ordinarily used as beverages.
Ten or 15 minutes usually suffices for extraction of the infusions after which the
leaves or grounds should be completely removed. The infusions should then he
cooled as quickly as possible and when at about 60° Fahrenheit they usually have
a dull muddy or turbid appearance and more particularly so with the tea infusions
when the tea used is of superior quality.
My improvements in the clarification and preservation of these or such like
infusions or decoctions are as follows:-
I add thereto and stir into same a small quantity of an aqueous solution of
tannic acid prepared by boiling tannic acid in water till the peculiar smell which
usually accompanies tannic acid is sufficiently driven off to be scarcely if at all
noticeable in the solution when cold and the solution should be employed cold or
nearly so. This solution of tannic acid is to be added until by its action a
flocculent precipitation is produced in the infusions. After stirring this in for a
short time the precipitate should separate from the mother liquor leaving it fairly
transparent and then the liquor should be decanted off or filtered free from the
precipitated matter as this matter would otherwise soon enter into a state of
change or decomposition harmful to the liquors and the ordinary bag filter of close
well woven cotton cloth is a suitable and convenient form of filter to use. On
pouring out the infusions into the bags the first of the liquor that passes through is
usually not quite bright and should be returned to the filter but if the treatment
with tannic acid has been sufficiently complete the liquor soon runs bright.
The filtered liquors should then be set aside in a place where a temperature of
about 60° Fahrenheit will not be exceeded and a few degrees lower is preferable
and in about 24 hours afterwards it should be examined and usually it will then
be found to have again become more or less dull and turbid acciding to the nature
of the liquors and to the quality and description of the material from which the
infusions were made.
This turbid or clouding matter is usually so exceedingly fine that it would be
very difficult to remove by any ordinary filtration, and to effectually collect and
remove it, I then treat the liquors with an aqueous solution of gelatine containing
an amount of gelatine which in its dry state would be equal more or less to
about 1 to 2 per cent. of the weight of the dry tea, coffee, cocoa or ginger employed

page_text: in making the infusions. This solution of gelatine I preferably use of a strength
of about 3 or 4 grains of gelatine to the ounce of water and preferably employ it
at a luke-warm temperature. On stirring this into the infusion a flocculent
precipitate will immediately form up gathering with it the preciptate already
formed in the liquor and the infusion should then be stirred gently and continuously
for about a quarter of an hour and, then poured into the filter bags and filtered
free from this precipitated matter. The resulting liquor will be pure and bright
and will show no tendency to further clouding or dulling on being kept. The
employment of gelatine at this stage is further beneficial to the liquor by com-
bining with and removing therefrom part of the excess of the tannic acid previously
added but a slight excess of tannic acid should still remain in the liquor to ensure
that all the gelatine has been precipitated and as a test of this the finished liquor
should still be capable of precipitating a small amount of gelatine if added. After
this last filtration I add an amount of salicylic acid equal to about one per cent. of
the dry material used in making the infusions and at same stage I sometimes add
a like amount, or thereabouts of an acid such as citric or tartaric, and the liquors
are then finished and ready to be used as essences for mixture with ordinary water
hot or cold and if diluted to a suitable degree with cold water they may be
bottled like wines and used similarly, or they may be bottled in combination with
water charged with carbonic acid under pressure to form effervescing and sparkling
beverages In the preparation of these clarified infusions it is preferable to use
water containing sulphate of lime in solution or if the water be naturally deficient
in this particular it should be artificially hardened by adding powdered gypsum
to it before the infusions are taken. If the infusions are required sweet the sugar
may be added to the water before making the infusion or it may if desired be
added to the bot infusion immediately after separation of the leaves or grounds or
at any other convenient time during the preparation of the liquors.
With some particular growths of tea which are exceptionally rich in native
tannic acid it is possible to obtain from their infusions a clarified liquor by treating
same with the gelatine solution alone and a flocculent precipitation will be obtained
therewith which will filter out from the mother liquor without any treatment with
the artificially prepared tannic acid but such liquors will still contain in solution
Inatter which if allowed to remain would be deleterious to their keeping qualities,
for although in this condition they might be preserved from absolute decay by a
copious application of salicylic acid yet the liquors would gradually undergo
alteration in consequence of the non-removal of this matter and as the precipitation
and removal of this matter are effectually accomplished by the tannic acid treatment
this treatment even with such infusions cannot therefore be omitted although the
infusions may be rendered transparent and bright looking without it.
After the last and final filtration care should be taken to prevent dust or other
impurities getting into the liquors as all such have a harmful effect.
For the successful carrying out of these improvements it is of importance that
the material used in making the infusions should be in fresh and good condition
and entirely free from even an incipient approach to decay from any cause and as
there are many different growths and qualities of tea, coffee, cocoa and ginger,
experience and taste will guide the selection and blending of same so as to obtain
the most desirable liquors and flavours.
Having now described the nature of my said Invention and in what manner the
same is to be performed I declare that I claim :-
First, The improvement in the clarification of aqueous infusions or decoctions of
tea, coffee, cocoa and ginger which consists in treating them with tannic acid until
a precipitation is produced this precipitation and the secondary or subsequent
precipitates being removed by filtration or otherwise all substantially as berein set
forth.
Second, The improvement in the clarification and preservation of aqueous
infusions or decoctions of tea, coffee, cocoa and ginger which consists in treating
them with tannic acid and salicylic acid the resulting precipitate and the secondary

page_text: or subsequent precipitates being removed by filtration or otherwise all substantially
as herein set forth.
Third The clarification and preservation of aqueous infusions or decoctions of
tea, coffee, cocoa, and ginger by the means and in the manner herein set forth.
In witness whereof I the said Samuel Cleland Davidson have hereunto set
my hand and seal this Thirty first day of July One thousand eight hundred
and eighty two.