IMPROVEMENTS IN CONCENTRATING MILK, AND IN OBTAINING CONCENTRATED EXTRACTS FROM TEA, COFFEE, AND CHOCOLATE
Year: 1856

page_text: LETTERS PATENT to Isaac Westhorp, of the City of London, for the.
"
Invention of "IMPROVEMENTS IN CONCENTRATING MILK, AND IN OBTAINING
CONCENTRATED EXTRACTS FROM TEA, COFFEE, AND CHOCOLATE." -A com-
munication from Gail Borden, a citizen of the United States of America.
PROVISIONAL SPECIFICATION left by the said Isaac Westhorp at the
Office of the Commissioners of Patents, with his Petition, on the
28th February 1856.
I, ISAAC WESTHORP, of the City of London, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN CONCENTRATING MILK, AND IN OBTAINING
CONCENTRATED EXTRACTS FROM TEA, COFFEE, AND CHOCOLATE;" to be.as follows:__
The first part of this Invention consists of a peculiar,receiver,, in which
fresh milk is to be retained in vacuo, and to which is fitted a suitable arrange-
ment for heating the milk by steam when required, and which is connected
with a vacuum pan or boiler in which the milk is concentrated.
And, secondly, this Invention consists of a-peculiar vessel, which I call a
displacer or extract filtering vessel, to be used in combination with the
above-named vacuum boiler for the purpose of obtaining extracts from tea,
coffee, or cocoa, all of which, when kept out of atmospheric influences,
may be preserved fit for use for a long period.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Isaac Westhorp in the Great Seal Patent Office on
the 28th August 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ISAAC
WESTHORP, of the City of London, send greeting.
year
of our
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent bearing date the Twenty-eighth day of February, in the
Lord One thousand eight hundred and fifty-six, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Isaac Westhorp, Her special licence that 1, the said Isaac Westhorp, my
executors, administrators, and assigns, or such others as I, the said Isaac
Westhorp, my executors, administrators, and assigns, should at any time agree
with and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for IMPROVEMENTS IN CONCENTRATING
MILK, AND IN OBTAINING CONCENTRATBD EXTRACTS FROM TEA, COFFEE, AND CHOCO-
LATE," a communication from Gail Borden, a citizen of the United States of
America, upon the condition (amongst others) that I, the said Isaac
Westhorp, my executors or administrators, by an instrument in writing
under ny or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in
the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Isaac Westhorp, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement:-
This Invention of improvements in concentrating milk, and in obtaining
concentrated extracts from tea, coffee, and cocoa, consists, firstly, in con-
centrating milk in vacuo by means of the apparatus herein-after described;
and, secondly, in preparing extracts of tea, coffee, and cocoa, either
combined with the concentrated milk or not.
But in order that my Invention may be fully understood, I will proceed to
describe the same; the Drawing accompanying and forming a part of this
Specification represents a vertical elevation of the apparatus.
A is a metallic vessel in which the milk is first placed or stored prior to

page_text: concentrating it. B is the vessel or receiver in which the concentration is
effected. C is a vessel forming a reservoir for the concentrated milk or
extracts. D, D, are a series of extract filtering vessels or displacers, which
are connected with the extract reservoir E. F is a vessel for obtaining
extract from tea. 9 is a pipe connected with an air pump and condenser
placed in some convenient part of the building. This pipe communicates
with the vessel B, and other pipes connected with the various vessels also lead
into it, so that the air from all or any of them may be readily exhausted, and
the steam or vapour arising from the fluids under operation condensed. his
a pipe communicating with a steam boiler for the admission of steam into the
vessel B. All the vessels to which heat is applied are fitted with double
bottoms, either for heating by steam or for cooling by means of a current of
cold water. is the exhaust pipe. is a pipe leading from the reservoir
into to the vessel B, and serving to convey the contents of A into the concen-
trator B. is a pipe leading from the vessel A to the air pump pipe g, and by
which a vacuum is obtained in the vessel A. mis a pipe by which the vessel
A is charged. n, a pipe fitted with a series of taps to which the extract
filtering vessels or displacers may be readily attached. o is a pipe which
connects the pipe n with the extract reservoir E. p is a pipe leading from
the vessel E into the pipe n. q is a pipe connecting the vessel B with the
reservoir C. is a pipe connecting the vessel C with the air pump pipe g, and
by which the vessel C may be exhausted of air. ' is a pipe for conveying steam
into the vessel (. 72 is an exhaust pipe. 3, a pipe for drawing off the
contents of the vessel C. s is a pipe connecting the extract reservoir E with
the air pump. s', a pipe by which the extract may be caused to flow into the
boiling or concentrated milk, or vice versa. 82 is a pipe for drawing off
the contents of the vessel E. The vacuum vessels A, B, C and E are each
provided with a tap a, b, c¹ and e¹ for breaking the vacuum when required.
u, u², are man-holes made in the vessels A, B, by which access may be had to
the interior for the purpose of cleansing the same as often as required. V, V,
are glass lights fitted in the upper part of the vacuum vessels to enable the
operator to inspect the state of the fluid within the vessels. Each of the
vessels A and B are provided with a barometer W and a thermometer X.
All the tubes connected or communicating with the several vessels are
fitted with taps, by which any one of them may be brought into.or thrown
out of operation at pleasure.
A is a vacuum reservoir in which new sweet milk is placed, and kept in
vacuum until it is required to be transferred or let into a vacuum boiler.
B is a vacuum boiler or pan for concentrating the milk out of contact with

page_text: the atmosphere.
g is a pipe connected with the vacuum boiler and to an
air
pump and condenser in some part of the building. The milk is boiled,
and concentrated in the vacuum vessel B by means of steam applied in the
known
When
and the application of the air pump and condenser.
way.
asteam pipe is employed in the inside of the boiler it should be so coiled
as to admit of access by the hand for cleaning. Both a steam pipe and a
double bottom or jacket may be employed at the same time. A thermo-
meter is inserted in the boiler B, and a vacuum gauge connected with it to
indicate the temperature of the boiling fluid, and the extent of the vacuum.
The milk which I desire to concentrate is placed in the vacuum reservoir
A as soon as practicable after the milking, where it remains until let into the
boiler for concentration. A vacuum is produced in the reservoir A by the air
pump, through a pipe connected therewith as l. k is a pipe communicating
with the reservoir and boiler. The reservoir and boiler are each provided
, with a man-hole. The reservoir is charged with milk through a pipe leading
to a series of caus of milk, the atmospheric pressure causing it to ascend the
pipe m. The boiling or working of the vacuum boiler is conducted in a
similar manner to vacuum pans in the manufacture of refined sugar in the
common way, except that I find it best first to place a small quantity of milk
in the boiler. I then, after the boiling has commenced, let the milk flow into
the boiler from the reservoir in a stream, gradually running in through the
pipe k, regulated by the cock connected therewith in such a manner as always
or during the principal part of the evaporating process to keep and maintain
the fluid in the boiler B at about the same consistence. The arrangement
and position of the vessels employed may be made to conform to buildings in
which they are placed. To facilitate the operation of concentration of milk
and extracts and to keep the vacuum boiler continually employed, I provide a
vacuum receiving vessel below and in connection with the boiler C, in which
I can at pleasure produce a vacuum by a connecting pipe leading to the
air pump, a cock being provided to let on and shut off the vacuum. When
the milk or extracts are sufficiently concentrated in the boiler B, they can be
let into the receiving vessel C by means of the cock in the connecting pipe q
without breaking the vacuum in the former vessel. This receiver is really
a small vacuum pan, and can be used to complete the process.
Milk may be concentrated to any degree required. I do not confine myself
to one standard. I have reduced it 83 per cent., but commonly 65 to 80 per
cent. The milk previous to concentration should be scalded by bringing it to
a temperature of 150° to 200 Fahrenheit, by which process the albumen is
coagulated, preventing coating on the bottom of the boiler, and rendering the

page_text: concentrated milk more soluble in water. This heating or scalding may be
done in the milk cans as they come from the farm in a steam bath;
it may
be simply a wood box heated by steam direct from a steam boiler; when
scalded, it should be placed in the reservoir A as soon as the temperature will
admit going into vacuum. It may be cooled by letting out the hot water in
the bath and admitting cold. For long keeping, I place the concentrated
milk in bermetically sealed vessels. This is done in the ordinary way, except
I prefer to heat up the milk in the vacuum boiler breaking the vacuum,
then transfer into the cans, and subject them to the bath only from one to
three or four minutes, seal and cool them in some speedy manner. For
keeping a few days or weeks, according to the temperature of the weather, it
is unnecessary thus to seal the milk. The concentrated milk having been
cooled is poured into the canisters, which are filled quite full, covered tightly,
turned up side down, and deposited in a cool place. When opened for use it
should not be covered; it should stand in a dry place, otherwise it is subject
to mould. Milk concentrated in this manner will keep good for a consider-
able length of time, and when dissolved in water will yield as much cream as
the original milk, showing that the qualities are not impaired by the process
of concentration out of contact with the air, as herein-before described.
The next part of my Invention relates to the process of obtaining extracts
of tea, coffee, and cocoa. In addition to the vessels employed in the con-
centration of milk, I employ the following, represented in the Drawing. E is
a vacuum reservoir in connection with and between the displacers D, D, D,
and the boiler B. It is used for three important purposes: first, to facilitate
and hasten the displacing process by producing more or less vacuum at
pleasure, without interfering with the operation of the vacuum boiler;
second, for holding intact from the air a supply of the liquid extract from
the displacers until wanted; third, by the power obtained of controlling the
vacuum at will, preventing all packing upon the diaphragins of the coffee
or other substances, which would follow if the displacers were in direct
connection with the vacuum boiler.
D, D, D, are displacers in connection with the extract reservoir E and
the vacuum boiler B. They are constructed so that the lower surface of
each shall perfectly fit the upper surface of the others, forming an air-tight
joint, and thus bring the upper displacers under the.controul of the vacuum,
thereby more perfectly exhausting the substances operated upon of their
valuable properties. Another important improvement in the displacers is
their connection with the vacuum reservoir by.air-tight tubes, effectually
protecting the extracts from contact with air.

page_text: The displacers are employed as follows:-The substance, the strength of
which I wish to extract, is placed upon a diaphragm fitted within each.
Boiling water, or in case of coffee, fresh hot milk, having been poured upon
the same, they are covered to prevent cooling, not, however, so tightly as to
prevent the admission of air when the vacuum is applied. The coffee or
other substance being sufficiently steeped, the connection between the dis-
placers and extract reservoir is opened, when the fluid by the operation of
the vacuum is forced through the coffee or other substance, conveying with
it into the extract reservoir the soluble matter, and leaving the insoluble
portions upon the diaphragm. For the diaphragm I use a perforated metal
plate, sufficiently strong to resist the action of the vacuum, and other known
means of filtering. For the purpose of procuring a more thorough dis-
placement of the extracts without delay, the displacers having been partially
exhausted, are placed upon the top of one charged with fresh material, and
the liquid being poured upon the uppermost, is by the force of the vacuum
forced through both. By this arrangement a complete displacement is
effected, and a uniform liquid extract obtained.
In obtaining the pure extract of.coffee, water is used as a displacing fluid,
but by the use of heated fresh milk I consider that a valuable improvement
has been effected, as owing to its greater specific gravity and its visced nature
the aroma is retained longer and better than when displaced by water; upon
the same principle as the delicate and fleeting aroma of flowers is collected
and retained more perfectly by saturation in oil. A very important saving
in time is also effected by this method, as the two processes of displacing
the coffee and combining the extract with milk are united in one.
In the combination of extracts with milk and sugar the proportions may
be varied as taste and fancy may suggest.
In the preparation of coffee I have more commonly used four parts in
weight of sugar, sixteen parts milk (to be reduced 80 per cent.), and five parts
roasted and ground coffee, but as coffee acts as an antiseptic in the preserva-
tion of milk, less sugar will answer or may be entirely dispensed with.
For the extract of tea I have employed two parts tea, three parts sugar, and
five parts in weight of milk (previous to concentration). In the preparation
of the extract of tea in combination with milk and sugar, it is important they
-should be concentrated at one operation; the sugar and milk having first been
admitted into the vacuum boiler, the infusion of tea is let into the boiling mass
by the connection with the reservoir E, below the surface, the watery portions
passing off in vacuo by means of the air pump, the full strength and flavor
are retained by the dense and tenacious body formed from the sugar and milk.

page_text: In the preparation of chocolate I have used six parts of finely prepared
melted cocoa, with seven or eight parts in weight of the concentrated milk,
and a like quantity of sugar. The milk and sugar being mixed in the process
of concentrating, the former should immediately after the completion be
thoroughly mixed with the melted cocoa in a vessel standing in a bath, or
in a vessel commonly used for mixing cocoa with sugar.
In procuring the extract of tea, I employ a displacer as F (in combination
with the extract reservoir) in connection with some known method of express-
ing the liquid strength of the tea after proper maceration in a separate and
covered vessel provided for the purpose. This displacer should not only be
in connection with the extract reservoir, but should be so constructed as
to prevent as much as possible the escape of the aroma.
In admitting the liquid extracts from the reservoir to the vacuum boiled for
concentration, there should be a separate pipe from the one through which the
reservoir is charged, otherwise the process of displacing and charging would
be suspended while letting into the boiler. Both the charge pipe and that for
discharging into and from the reservoir, should project into the same some two
to four inches according to the convexity of the vessel. In the preparation of
large quantities of coffce and other extracts, I use the vacuum reservoir A,
for preserving in a perfect state a sufficient quantity of fresh sweet milk
for the purpose. It is not necessary to scal hermetically extracts prepared
agreeably to the process above described. After a sufficient concentration
the extract should be thoroughly cooled. I do this in the vacuum boiler
by stopping off the steam, and letting into the jacket, or double bottom,
cold water. This may be accomplished by a proper connection with the
steam pipe. After cooling, I transfer the extract into canisters, or wide
mouth bottles filling as full as possible, stop tight, securing the cover or
cork with tin foil or other known means of excluding air, and turn the
cans or bottles upside down letting them remain in that position for
a time.
Each of the vacuum vessels should be provided with a vacuum
gauge. The use of the cocks in the connections will obviously appear to
the manufacturer.
Having thus explained my Invention I would state that I am well aware
that sugar and various extracts have been and are now concentrated in vacuo
under a low degree of heat to prevent discoloration or burning. I do not
claim boiling milk and concentrating it in a vacuum vessel for such a purpose,
my object being to exclude the air from the beginning of the process to the
end, to prevent incipient decomposition. This is important, and I claim the
discovery, I am aware that scalding milk to improve its preservative qualities

page_text: has long been known, and that it has been kept in hermetically sealed
vessels; I do not claim these processes.
And I believe milk and extracts of tea and coffee have never been combined
out of contact with the air while filtering and boiling, in which the principal
value of my Invention consists. If the liquid extract of coffee and tea be
exposed to the air while in the process of evaporation (unless done very
slowly), it must be effected undera high temperature, which would necessarily
evolve and throw off the aroma which it is so important to preserve.
I do not claim any process of filtering or displacing as heretofore practised,
and I wish it understood that I do not confine myself to the precise arrange-
ment of the apparatus herein-before described and shewn, as the same may
be varied both in arrangement and detail without departing from the
Invention; and what I claim and desire to secure under the herein-before
in part recited Letters Patent, is,
Firstly, preserving milk in a vacuum reservoir, until it can be concentrated
as herein-before substantially described and shown.
Secondly, concentrating milk in a vacuum vessel as in the boiler B, for the
purposes set forth.
Thirdly, obtaining extracts.of tea, coffee, and cocoa, by means of the appa-
ratus, and in the manner herein-before described and shewn, or any mere
modification thereof.
In witness whereof, I, the said Isaac Westhorp, have hereunto set my
hand and seal, this Twenty-sixth day of August, in the year of our
Lord One thousand eight hundred and fifty-six.
J. WESTHORP. (L.S.)