IMPROVEMENTS IN THE TREATMENT AND PRESERVATION OF YEAST
Year: 1863

page_text: LETTERS PATENT to David Barker, of Milton Street, Wandsworth Road,in
the County of Surrey, Corn Merchant, for the Invention of "IMPROVEMENTS
IN THE TREATMENT AND PRESERVATION OF YEAST."
Sealed the 12th December 1863, and dated the 18th June 1863.
PROVISIONAL SPECIFICATION left by the said David Barker at
the Office of the Commissioners of Patents, with his Petition, on the
18th June 1963.
I, DAVID BARKER, of Milton Street, Wandsworth Road, in the County of
Surrey, Corn Merchant, do hereby declare the nature of the said Invention
of "IMPROVEMENTS IN THE TREATMENT AND PRESERVATION OF YEAST," to be as
follows:-
This Invention relates to certain processes whereby ordinary brewers' yeast
can be preserved in a state fit for use during a longer period than by any of
the methods previously employed. When the yeast is intended to be used in
the manufacture of bread it is intimately mixed with water and allowed to
settle, when the water is poured off or separated by filtration, the sediment
being treated with water in a similar manner until the bitter principle is
entirely removed therefrom. The pure yeast thus obtained is then dried and
mingled with a proportion of farinaceous matter, a small quantity of a suitable
alkali being added thereto. In preparing the yeast for the use of distillers
the washing thereof may be dispensed with, inasmuch as the retention of the
Paine 8d I

page_text: bitter principle is not objectionable for the purposes of distillation. The yeast,
as obtained from the fermenting vessels, may, therefore, be at once mixed with
the farinaceous matter, and the cost of manufacture may be still further
reduced bysubstituting for a portion of the farinaceous material a correspond-
ing quantity of plaster of Paris, or other calcareous substance, which may
be
thus employed without injury to the fermenting properties of the yeast.
The yeast, having been prepared as aforesaid, maybe reduced to ar y desired
form by pressure or otherwise for convenience of storing and carriage.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said David Barker in the Great Seal Patent Office on the
18th December 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
BARKER, now of Ceylon Street, Battersea Park, in the County of Surrey, but
formerly of Milton Street, Wandsworth Road, in the said County, Corn
Merchant, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of Juue, in the year of our Lor
One thousand eight hundred and sixty-three, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said David Barker, Her special licence that I, the said David
Barker, my executors, administrators, and assigns, or such others as I, the said
David Barker, 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
THE TREATMENT AND PRESERVATION OF YEAST," upon the condition (amongst
others) that I, the said David Barker, 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 David Barker, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following

page_text: statement, reference being had to the Drawing hereunto annexed, and to
the letters marked thereon (that is to say):-
My said Invention relates to certain processes and modes of treatment
whereby the ordinary yeast obtained in the manufacture of beer, spirits, or
wine, can be preserved in a state fit for use during a longer period than by
any of the methods previously employed, the yeast so prepared and preserved
being applicable to the purposesof making bread, and also in the manufacture
of beer and spirits.
I will, in the first place, describe the method adopted when the yeast is the
ordinary brewers' yeast, and is to be employed in bread making. The yeast
to be treated in accordance with my Invention may be either in a pressed or
liquid state, and having added thereto about one per cent. of caustic soda or
caustic potash (potash being preferred by me) it is put into a filtering vessel
with spring water, with which it is intimately mixed, the result being that by
the process of filtration the bitter principle derived from the hops and other.
impurities are carried off, the yeast being left in a perfectly white and pure
state. It should then be placed in canvas bags and submitted to the pressure
ofa screw or hydraulic press for the purpose of separating the liquid combined
therewith. Having thus obtained the pure yeast, I mix with it a proportion
of caustic soda or caustic potash (potash being employed by preference) say.
about two per cent., a proportion of about ten to twenty-five per cent. of
farinaceous matter (arrowroot being preferred) being afterwards added. The
materials thus combined should then be thoroughly mixed and incorporated,
and finally entirely dried and deprived of all moisture, either by being spread
thinly upon iron plates heated by steam, hot air, or gas, or by exposure to
the air, the processes of mixing and drying being, however, most rapidly
and effectually performed by the machine or apparatus represented in the
Drawing hereunto annexed and which I will now describe.
The drying apparatus consists of a cast-iron frame, on which is mounted a
cast-iron steam cylinder, the face thereof being perfectly true, and so arranged
that its temperature and speed can be regulated at the will of the operator.
In immediate proximity to the cylinder, and on the same frame, are fixed two
iron rollers, also perfectly true, the same acting as grinding rollers, and re-
volving at the relative speed of nine to twelve. The rollers are placed in a
frame so as to be capable of being adjusted with regard both to themselves and
also the drying cylinder. The drying cylinder rotates at the speed of six to nine
with reference to the grinding rollers. Immediately over the grinding rollers
is a hopper for the admission of the materials, such hopper having within it

page_text: three shafts with blades or knives, which act as masticators to roughly incor-
porate the materials under treatment. The yeast is introduced at one side of
the hopper,and the farinaceous matter at the other, in the centre thereofbeing
a perforated tube through which the requisite quantity of alkali is supplied
from a small self-acting vessel at the top of the hopper. The mode of operation
is as follows: The materials having been introduced through the hopper are
roughly mixed or incorporated by the revolving blades or knives, and passing
between the grinding rollers are thoroughly ground. Upon leaving the grinding
rollers the substances under treatment are carried up by the drying cylinder
(which is heated by any of the ordinary and known methods) in the form of
a thin film, which by the time the cylinder has nearly made one revolution
is sufficiently dry and falls off into a shoot provided for that purpose; or, if
it has not separated from the surface of the cylinder it is removed by a steel
blade so placed as to scrape off all substances adhering to the surface of the
.cylinder at the completion of each revolution.
In the annexed Drawing A is the hopper; a¹, all, the divisions thereof for
the respective admission of yeast and farinaceous matter; is the central
tube for the introduction of the alkali; c, c, c, are the masticating blades or
knives; d, d, the grinding rollers revolving in the directions shewn by the
arrows; B, the drying cylinder, D being the shoot for the reception and con-
veyance of the yeast when dried, and C, the steel blade, before mentioned,
regulated by the screw e. The machine may be actuated by steam or any
suitable motive power.
It may be here observed, that when the yeast is obtained from the manu-
facture of spirits or wine the filtering process may be altogether dispensed
with, there being no bitter principle existing in such yeast.
1 will now proceed to describe the preparation of the yeast when it is to be
employed for the purposes of brewing or distilling. As the presence of the
bitter principle is not detrimental to these operations, the process of washing
and filtering may be dispensed with, the yeast, either in a pressed state or as
obtained direct from the fermenting vessels, being used in combination with
the farinaceous matter, as before mentioned. In order, however, to lessen the
cost of manufacture, plaster of Paris or other analogous calcareous substance
may be substituted for a portion of the farinaceous matter, about three per
cent. of alkali being added to the other materials. The substances under
treatment are introduced into the drying machine and the manufacture com-
pleted as before described.
The preparation of the yeast, for whatever purpose it may be intended,

page_text: having been completed as herein-before described, it may be reduced to any
desired form, by pressure or otherwise, for convenience of storing and car-
riage, or it may be preserved in a state of powder.
I may here observe that the yeast so prepared in accordance with my
Invention as aforesaid, is perfectly free from any tendency to putrefaction or
to contract mould, and will preserve its fermentative properties uninjured
for a great length of time. The effect of the combination of the farinaceous
matter with the yeast is to support or sustain the vital principle of the
latter, while the presence of the alkali has the effect of suspending the
active developement of the process of fermentation, the fermentative
quality remaining dormant until the yeast is placed under conditions
favorable to its action.
Having thus explained the nature of my said Invention, and also the
manner in which it is to be performed, I would wish it to be distinctly
understood that I do not claim the construction of the drying machine
herein-before described as being my Invention, but what I consider novel
and original, and therefore claim as my Invention, is, the treatment and
preservation of yeast by the processes and in the manner herein-before
substantially set forth and described.
In witness whereof, I, the said David Barker, have hereunto set my hand
and seal, this Eighteenth day of December, in the year of our Lord
One thousand eight hundred and sixty-three.
5
Witness,
E. P. H. VAUGHAN,
15, Southampton Buildings,
Agent for the Patentee.
DAVID BARKER. (L.S.)