Improved Process for Preserving Milk.
Year: 1895

page_text: $1-
Date of Application, 23rd Aug., 1895
Complete Specification Left, 29th Apr., 1896-Accepted, 22nd Aug., 1896
ft..
Improved Process for Preserving Milk.
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WILLIAM CHARLES KAUFMANN 3. Chapel Place Cavendish Square W. London
HENRY WILLIAM BUTLER "The Retreat". Newlands Park Sydenham Kent do
hereby declare the nature of this invention to be as follows:-
Up to present time experiments have proved, that milk can be preserved fresh
for only a short period. Now we claim for our invention,,that milk treated by our
process will keep for several years. Our process is as follows:
The milk is heated by steam or by water in a air-tight boiler for 32 minutes
& then driven by a stream of carbonic acid gas through pipes surrounded with ice,
in order to cool it down to 5 degrees Centigrade, without coming in contact with
the atmosphere. It is then pumped with carbonic acid gas into a cylinder, where
it is charged & saturated by this gas, from thence it is drawn off through a pipe
into any suitable vessel by a machine, which eliminates all atmospherical air. from
the vessel, before the milk enters it. The vessel is then closed & kept airtight
& the milk will keep fresh as long as the pressure within the vessel is greater.than
without & when the vessel is opened, it will retain all its original qualities
& conditions even after a lapse of several years.
I.
Dated this 23rd day of August 1895.
W. C. KAUFMANN.
H. W. BUTLER.
Improved Process for Freserving mIK.
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WILLIAM CHARLES KAUFMANN 3 Chapel Place, Cavendish Square, London, W.,
Chemist and HENRY WILLIAM BUTLER "The Retreat Newlands Park
Sydenham in the County of Kent Agents and Merchants 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:
Many experiments. have been made within the last few years, in preserving milk,
none of which have shown any remarkable. result. It is possible to keep milk for..
a few days by pasteurizing it, i.e. by scalding, it up to 70% Centigrade,, and..
then. cooling it suddenly. down, to 10%. It is possible, too, to keep it in soldered...
tins for years, by sterilizing it, i.e.. beating, it, when soldered in,tins, or bottles, up,
to 125 Centigrade for, half an hour; but then, all its good qualities are destroyed,
and can never be restored. an
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We claim now a new process composed of several manipulations, by which it is
possible to preserve milk for years, without losing, any of its good, qualities...;
To study this process, and, to understand, why, we claim it to be new, it is,
necessary, to know, what amount of changing, iar, transformations. the different..
constituents of milk undergoes, when heated to the different degrees of temperature.
These transformations are as follows
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1stly. The minute fat globules melt already at a temperature of 35°, Centigrade,
but when cooled down they will solidify again, and no difference can be seen between

page_text: fresh milk, and milk heated up to 35°. At 70° however milk gets quite another
flavour, and one can distinguish that it has been cooked, and we call it the
"cooked" flavour which is generally disliked.
2ndly. The reason of this changing is to be found in consequence of the gaseous
matters having escaped at this temperature. This strange taste, however slight,
becomes stronger when milk is scalded up to 72°. At this temperature the
albumen coagulates, and makes the milk thicker, renders it less transparent, and
less digestible, as coagulated albumen is not soluble in water.
The cooked taste or flavour predominates more after the albumen is coagulated,
and becomes stronger the more the milk is scalded up to the boiling temperature.
We do not know of any process that will restore the fresh flavour after the
albumen has become coagulated.
3rdly. After reaching the boiling temperature the milk sugar begins decomposing
and becomes caramel, and then the milk turns brown when the temperature 125° is
reached. At this stage it gets the color of chocolate, and tastes like burnt sugar,
consequently the original qualities of taste and color can never be restored.
A temperature less than 125° Centigrade not being sufficient to destroy all the
bacteria and germs in milk, it is, therefore, not possible to sterilize milk only, by
scalding it up to this temperature without it losing its qualities.
In order not to destroy the qualities of the milk, we scald it only up to 70° and
cool it suddenly down to 10°..
By this process of "pasteurizing" the bacteria in it are killed for a few minutes,
but not their germs, as after a few minutes these germs will grow again into new
bacteria.
To hinder the growth of the germs, and to keep them so to say stunned, viz. :-in
a sleeping state, we found out that they must be kept under a pressure of at
least 30 lbs.
If this operation is done immediately after the milk has been "pasteurized" and
without it coming into contact with the open air, it is possible to keep it for any
length of time.
The first process of pasteurizing the milk can be carried out, even without
scalding and cooling it, viz. :-by adding such chemicals known under the name
of "preservatives" in such quantities as will keep the milk sweet for 60 hours,
for instance; 35 gr. of boric acid to a gallon of milk. This quantity would
destroy the bacteria in it for a few minutes as well as it would be done by
"pasteurizing" it.
Our process of preserving milk without spoiling its qualities, consists therefore
of two operations, the intention of which is :-
Istly. Killing the bacteria, and so to say stunning the germs.
2ndly. Keeping the germs in this condition by putting the milk under a pressure.
The operations to reach this purpose can be carried out in several ways, two of
which we will name
1. Add to the milk such a quantity of any preservative, as would keep it sweet
for 60 hours, then fill it into tins, and well solder same down, or put the milk
into tins (quite up to the top) solder same; and put them for 10 minutes into
water of 72° Centigrade. The contents will then be at a temperature of 70° for
five minutes, afterwards cool it suddenly down, by putting the tins into iced water
until the contents may be reduced to a temperature of 10°.
After thus having destroyed the bacteria in either way, press in by a machine
(adapted for the purpose) the cover and the bottom of the tin, until there is a
pressure of more than 30 lbs. inside the tin.
11. Put the preservative in the milk as before or, scald it in an airtight covered
vessel up to 70°, and then cool it suddenly down to 10° in the same vessel, and
press the milk by a stream of carbonic (or any other indifferent gas) acid gas
into an apparatus, by which it may be filled into bottles, casks, jars and the like
(without coming into contact with the air) or any other injurious gases, under a
pressure of more than 30 lbs.

page_text: Milk preserved in this way will keep for years, and after the pressure has gone,-
and the gas has escaped, it caunot be distinguished from fresh drawn milk.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be applied, and performed, we declare
that what we claim is :-
An improved process of preserving milk characterized by the two foregoing
processes following immediately one after the other-
1stly. To destroy all bacteria in milk, and to prevent the germs from growing,.
and spoiling the milk, either by the addition of any preservative suitable to keep
milk sweet and fresh for 60 hours in the open air, or by sealing the milk in a.
closed vessel, and scalding it up 70° Centigrade for five minutes, and cooling it.
suddenly down to 10° Centigrade in the same vessel.
2ndly. To fill thus prepared milk into vessels, and bring it under a pressure of
more than 30 lbs., either by diminishing the size of the vessel, or, by charging the
milk with compressed gas.
Dated this 27th day of April 1896.
HENRY WILLIAM BUTLER.