IMPROVEMENTS IN THE PRESERVATION OF MEAT AND THE CONCENTRATION OF ITS JUICES
Year: 1865

page_text: LETTERS PATENT to Theophilus Redwood, of No. 19, Montague Street,
Russell Square, in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN THE PRESERVATION OF MEAT AND THE CONCENTRATION OF
ITS JUICES."
Sealed the 1st May 1866, and dated the 10th November 1865.
PROVISIONAL SPECIFICATION left by the said Theophilus Redwood at
the Office of the Commissioners of Patents, with his Petition, on the
10th November 1865.
I, THEOPHILUS REDWOOD, of No. 19, Montague Street, Russell Square,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE PRESERVATION OF MEAT AND THE CONCEN-
TRATION OF ITS JUICES," to be as follows:-
I effect the preservation of meat by immersing it for some time in a
substance kept liquid by heat, which substance exerts no injurious effect
on the meat, but affords the means of raising its temperature to 212° Fahr.
or higher, and at the same time causes the expulsion and exclusion of air
from it, and as this liquid becomes a tenacious solid on cooling, the meat
after being heated in it to a sufficient extent, on being taken out carries a
film of the liquid over its surface, which forms a solid coating that continues
to exclude the air. This coating, in which the meat is hermetically sealed,
may be increased in thickness to any required extent by repeatedly dip-
ping the meat into the hot liquid and allowing each successive layer of
liquid to be congealed by exposure to the air.

page_text: The substance which I have found most completely to fulfil this object
is parafin, but wax, spermaceti, or stearic acid, used separately or added
to parafin, or a mixture of any or either of these substances, in the propor-
tions of, say, five or ten per cent. (but I do not confine myself to such
proportions) may be employed, although not so advantageously as parafin
alone. During the immersion of the meat in the hot parafin the juices are
concentrated by the evaporation of the aqueous parts, and this may be
carried to any required extent so that the meat may be thus condensed,
and if desired it may be rendered hard and dry. In conducting this part
of the process I keep the parafin at a temperature of about 240° Fahr., by
which means rapid evaporation and concentration of the juices are effected;
the meat is afterwards cooled by exposure to the air, or by allowing the
parafin in which it is immersed to cool to near its congealing point, or by
transferring the meat to a part of the vessel containing the parafin where
the temperature is maintained at about 140° Fahr.; and finally the meat is
coated with parafin by removing it from or passing through the parafin, in
which the latter is at a temperature of about 140° Fahr., and dipping it as
often as necessary to give it the required coating. I also effect the con-
centration of meat juice when separated from the meat by boiling it in
melted parafin at a temperature above 212° Falır., by which means rapid
evaporation is effected, while air is excluded from the evaporating
liquid.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Theophilus Redwood in the Great Seal Patent Office on
the 10th May 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THEOPHILUS
REDWOOD, of No. 19, Montague Street, Russell Square, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of November, in the year of our
Lord One thousand eight hundred and sixty-five, in the twenty-ninth
year of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Theophilus Redwood, Her special licence that I, the said
Theophilus Redwood, my executors, administrators, and assigns, or such
others as I, the said Theophilus Redwood, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time and

page_text: 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 THE PRESERVATION OF MEAT AND THE CONCENTRATION OF
ITS JUICES," upon the condition (amongst others) that I, the said Theophilus
Redwood, my executors or administrators, by an instrument in writing
under my, 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 Theophilus Redwood, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
The object of my Invention is to provide for the prevention of putre-
factive decomposition and other changes which render animal substances
unfit for use as food. It is well known that these changes may be pre-
vented by excluding atmospheric air or gases containing uncombined
oxygen from contact with animal matter after it has been exposed to
a temperature of about 100° centigrade, and my Invention consists in
my improved method and means of accomplishing the object aforesaid.
I effect the preservation of meat by immersing it for some time in a
substance kept liquid by heat, which substance exerts no injurious
effect on the meat, but affords the means of heating it to 100° centi-
grade or higher, and at the same time causes the expulsion or exclu-
sion of air from it; and as this substance becomes a tenacious solid
on cooling, the meat, after having been heated in it to a sufficient
extent, on being taken out carries a film of liquid over its surface,
which forms a solid coating that continues to exclude the air. This
coating, in which the meat is hermetically sealed, may be increased in
thickness to any required extent by repeatedly dipping the meat into the
hot liquid and allowing each successive layer of liquid to be congealed by
exposure to the air or otherwise. The substance which I have found
most successfully to fulfil this office is paraffin, but wax, spermaceti, or
stearic acid, used separately or added to paraffin, or a mixture of any or
either of these substances in the proportions of, say, 5 or 10 per cent. (but
I do not confine myself to such proportions), may be employed, although
not, I believe, so advantageously as paraffin alone. When fresh meat is

page_text: operated upon the juices are concentrated during the immersion of the
meat in the hot paraffin by the evaporation of water, and this may be
carried to any required extent, so that the meat may be thus condensed,
and if desired it may be rendered hard and dry. In conducting this part
of the process I keep the paraffin at a temperature between 100° and 120°
centigrade, by which means a more or less rapid evaporation and concen-
tration of the juices are effected. The meat is afterwards cooled by
exposure to the air or by transferring it to another part of the vessel, or to
another vessel in which the process is performed where the temperature
is sufficiently low to cool the meat, so that on afterwards passing it through
or putting it into the liquid paraffin, some of the latter will be congealed
on its surface, or will congeal when brought into contact with the air.
The coating of paraffin, formed as already described over the surface of
the meat, may be increased in thickness by repeatedly dipping the coated
meat into liquid paraffin at a temperature a few degrees above its melting
point, and allowing each successive layer to harden by exposure to the air.
The meat may also be further protected after having been thus coated by
putting it into a suitable vessel or receptacle, and then pouring melted
paraffin over it so as to envelope the meat, or by wrapping the coated
meat in some coarse fabric and then dipping it together with the wrapper
into melted paraffin.
The most simple arrangement for conducting the process in the preser-
vation of fresh meat consists in having two vessels in which melted paraffin
can be kept at the required temperatures, either by fires placed beneath
them, or by coils of steam pipe fixed against their inner surfaces, or by
steam jackets, such as are usually provided to jacketed steam pans. One
of these two vessels should contain melted paraffin at a temperature of
from 115° to 120° centigrade, and should be provided with efficient means
for maintaining this temperature when the meat to be operated upon is
introduced into the paraffin. The other vessel should contain melted
paraffin at a temperature only a few degrees above its melting point, and
as this varies in different samples of paraffin, it may be stated to range
from 43° to 56° centigrade. This vessel should also be provided with
means for keeping the temperature of the paraffin it contains as nearly as
possible at one fixed point. Before putting the meat into the paraffin
each joint or separate mass should have an iron wire attached to it, by
means of which it may be suspended either in this or a subsequent part
of the process, and it is then to be inmersed in the paraffin contained
in the first-described vessel, either suspended by the wire or placed in a

page_text: suspended dish and subjected to the temperature of from 115° to 120°
centigrade for such a length of time as shall cause every part of the
meat to be heated to at least 100° centigrade. To ensure the accom-
plishment of this object a piece of meat weighing about ten pounds
should be kept in the hot paraffin for at least one hour, but the
time may be extended to two or three hours if it be intended for long
preservation or for warm climates. When the meat is intended for warm
climates it is also desirable to exclude bones, and especially marrow bones.
Several pieces of meat may, however, be put together and closely packed
in a metallic vessel of the form of a pail, so as to fill it, and this vessel
with its contents may be immersed in the hot paraffin for the required
time. This arrangement as well as that of suspending the meat in a dish
presents the advantage of its keeping the juices that may escape from the
meat in contact with it, so that most of the juices will be re-absorbed in a
concentrated form during the process of heating. After having subjected
the meat to the temperature specified for the required length of time it is to
be removed from the vessel in which this part of the process has been con-
ducted;
if the pieces of meat were separately suspended by the wires or in
the suspended dish they must be quickly transferred to the vessel containing
the cooler paraffin, where they are to be immersed so as to be excluded
from the air, and they must be left in this position until they have cooled
down to the temperature of the paraffin in contact with them; they may
then be taken out and exposed for a short time to the air, when a film of
paraffin will congeal over the surfaces of them, and this may be increased
in thickness by repeatedly dipping them into the paraffin and allowing each
successive film to harden in the air. When a sufficiently thick coating has
been formed over the meat, the wire by which it is suspended may
be removed and the hole through which it passed filled with melted
paraffin, which latter result may be effected by applying the warm blade of
a knife to the part of the paraffin through which the wire passed, so as to
melt the paraffin and thus fill up the hole. This part of the coated meat
may then be dipped into melted paraffin so as to form an additional coating
that will secure the exclusion of air.. If, as already described, several pieces
of meat were put together into a containing vessel and thus immersed, this
vessel with its contents, including the melted paraffin that surrounds and
covers the meat, may after the heating process is concluded be put into any
suitable place where it may be most conveniently cooled. When it has
become cold and the paraffin congealed the contents of the vessel should
be turned out, and this will be easily effected if the vessel have the slightly

page_text: conical form of an ordinary pail. It must now be dipped several times in
the melted paraffin, so as to cover those parts of the meat that were in con-
tact with the vessel and thus to exclude the air. This will be found to be
a suitable method of preparing meat for exportation, as large quantities can
be operated upon at once, and the masses of meat thus cemented together
by the intervening paraffin may be advantageously packed in vessels similar
in form and size to those used in their preparation. This latter method of
operating, with slight variation, may be adopted when the meat is required
to be dried by the evaporation of its juices, but in this case the meat
should be cut into slices and placed in a shallow vessel, which is to be sus-
pended in the hot paraffin and kept there until the required amount of
evaporation has been effected. At the end of the operation the meat in
its containing vessel is to be transferred to the cooler paraffin, where it is
to be allowed to cool until on taking it out it will retain a film of paraffin
that will congeal on its surface. The coating of paraffin must be sufficiently
thick to exclude the air and to bear without fracture the treatment to
which it will be subjected as an article of commerce. When prepared in
the manner herein described the meat will be fit for use as food even after
it has been kept for several months, provided the coating of paraffin has
remained unbroken and has continued to exclude air from contact with the
meat. The coating may be easily removed when the meat is required for
use as food, by breaking and peeling off the greater part of the paraffin
and then putting the meat into hot water, so as to melt the remaining part
of the paraffin and cause its entire separation from the meat. The melted
paraffin will rise to the surface of the water, and may, together with that
otherwise removed from the meat, be kept for subsequent use. Although
in the operations I have described I prefer to use paraffin as the preservative
agent, yet wax, spermaceti, or stearic acid, used separately or mixed in
various proportions, or a mixture of one or more of these with paraffin, may
be substituted for paraffin, the methods of operating remaining in other
respects the same as herein described.
In witness whereof, I, the said Theophilus Redwood, have hereunto
set my hand and seal, this Seventh day of May, in the year of our
Lord One thousand eight hundred and sixty-six.
T. REDWOOD. (L.S.)