Improvements in the Manufacture of Beer.
Year: 1892

page_text: Date of Application, 9th Mar.. 1892-Accepted, 23rd Apr., 1892
Improvements in the Manufacture of Beer.
A communication from THE PFAUDLER VACUUM FERMENTATION COMPANY,
of Rochester. in the County of Monroe and State of New York, United.
States of America.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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:-
In the manufacture of lager beer, so-called, as commonly practised, the wort
after mashing, extracting, boiling, hopping, cooling and fermenting in the main
fermenting rats is transferred to ruh or storage vessels wherein it undergoes a
secondary or subsidiary fermentation for the purpose of aging or ripening it. Until
within the last few years it was always allowed to remain in these casks for a period
of from one to five months, and permitted to attain the desired degree of ripeness
by prolonged after fermentation unaided by any hastening appliance; and to
attain the degree of ripeness necessary to secure the best quality of the product
several months were required, the time being shortened to a period of from one to
two months at the expense of the quality of the product and only in cases of
urgent demand.
Within the past few years the aging in the ruh or storage
casks has been extensively conducted under the so-called Pfaudler Vacuum
Process, by which, the beer, in the secondary fermentation attains in a period
of about seven days the same qualities that it would acquire in a period of fully five
months if aged or ripened by the common process above mentioned.
After the beer has attained the desired degree of ripeness, whether by either of
the modes of procedure above referred to, or by any other, it is ordinarily transferred
to bunging casks in which it is finished for the market. In some processes of
manufacture shavings or chips are used in these finishing casks and they are then
called shavings casks or chip casks; in others chips or shavings are dispensed with,
and these casks are then usually referred to as bunging casks or finishing casks.
Whatever the special process employed with them, however, they are used for the
common purpose of containing the beer while it is being saturated with carbonic
acid gas and more or less clarified to fit it for the market. The saturation consists
in causing it to become impregnated with carbonic acid gas in such quantity as to
give it the requisite degree of life and effervescence to fit it for the market. This
is necessary, since while in the ruh or storage casks, the fermentation of the beer
has been substantially exhausted, and the gas suffered to escape, so that the beverage
contains by far too little carbonic acid gas to suit the public taste. The most usual
treatment in the finishing casks is with chips and "kraeusen," or young beer
derived from the main fermentation. The "kraeusen" operates as an active ferment
exciting a new and very vigorous fermentation in the beer under treatment, thus
generating carbonic acid gas in large quantities, a sufficient portion of which is
retained in the beer to impart to it the required effervescent quality. The reten-
tion of the required quantity in the beer is effected generally at the present time
by means of a banging apparatus, the office of which is to retain the beer under a
predetermined pressure of the self-generated carbonic acid gas, allowing the surplus
to escape. Incidentally the beer in the finishing casks is supplied usually with a
clarifying medium, such as isinglass, which, having a slightly greater specific
gravity than the beer settles to the bottom in one or more films, carrying with it
the suspended impurities, which become imprisoned among the shavings, where
shavings are employed. As a final step, with or without previous clarification in
the finishing casks, whether by means of isinglass or otherwise, it has become of

page_text: late years a common practice to filter the beer while on the way from the finishing
casks to the shipping packages.
By a recent invention, now being practised by us, the main fermentation of the
beer, instead of being conducted in open vats, as heretofore, is conducted in closed
fermenting vessels under a partial or approximate vacuum, the beer undergoing
fermentation being maintained meanwhile at the requisite low temperature for
lager beer, which is a product of lower or bottom fermentation. In other words,
by the invention aforesaid, the wort, prepared in the usual way and pitched with
yeast, is confined in closed fermenting vats and atmospheric air and carbonic acid
gas are abstracted by means of a vacuum pump from the upper part of the vessel
as they accumulate, thereby producing a partial or approximate vacuum under
which the fermentation progresses; and it is found that by this treatment the
main fermentation is very much more expeditiously and perfectly conducted than by
the process heretofore employed. Incidentally the invention before referred to also
includes the introduction, once or oftener, as may be required, of purified atmospheric
air into the fermenting vat during the progress of fermentation for the purpose of
revivifying the yeast, and it also contemplates a coalition with the above mentioned,
whereby both the main fermentation and secondary or subsidiary fermentation may
be conducted in vacuo by one continuous process, and preferably in the same
vessel.
The present invention relates to the treatment of beer subsequent to the aging
or ripening stage, for the purpose of clarifying and saturating it with the required
quantity of carbonic acid gas; and it consists broadly in passing the beer after the
completion of the secondary fermentation through a filtering medium, and in
saturating it with carbonic acid gas derived either from previous fermentation of
beer or from other sources.
The invention consists further in certain preferred methods of carrying out the
process, which will be explained in detail hereinafter.
In the accompanying drawings-
Figure 1 is a diagrammatic view of an apparatus for carrying the invention into
effect, and embodying the other invention practised by us herein before referred to,
which is preferred, under certain circumstances, to employ in connection with
it; and
Figure 2, a similar view showing a modification in the matter of introducing
carbonic acid gas, whether derived from previous fermentation or from extraneous
sources, into the beer after filtration.
A represents the main fermentation vessel, which in Figure 1 is of a character
adapted to carry out the other complete process as the same has been practised
by us, before referred to, and in Figure 2 is of a character to permit the
carrying on of the other process involving the employment of separate vessels
for the main and secondary fermentations, and for either purpose it is provided
with a valved exhaust pipe, t, leading to a vacuum pump, B. Means for with-
drawing the contained liquid are found in the racking pipes which pipe in the
construction shown in Figure 1 leads directly to a filter C, of common construc-
tion. In case the main and secondary fermentation shall be conducted in separate
vessels, as shown in Figure 2, the pipe s leads to the secondary fermentation
vat A, and the beer is thence transferred through the pipe to the filter C.
When the secondary vessel A' is employed the vacuum exhaust pipe t', which
leads from the top thereof, may connect with the pipe leading to the pump B.
It is advisable, especially if a vacuum is to be created above the beer in either
vessel, in accordance with the preferred mode of operating the process, that the
main fermentation vessel A and also the secondary fermentation vessel A' shall be
substantially of a construction in common use for carrying out the process above
described, and such a vessel is illustrated in the drawings. It is provided with a
manhole and with proper valve ports for the admission of air for the purpose of
racking and for the introduction of the beverage before fermented. The
drawings show also the employment of air admitting and agitating mechanism D

page_text: which forms part of the construction employed by us with the other process
before referred to as practised by us. Its use in carrying out the process, though
desirable, is not essential, and it may be stated that the provision of a vacuum,
though desirable in the progress of fermentation, is not essential to the carrying
out of the process as hereinafter claimed, it being merely necessary in the
interests of economy to collect for utilization the accumulating carbonic acid
gas. As will presently appear the gas obtained from the fermentation vessels
may be led to a gasometer or receiver where it is retained ordinarily under
pressure, or be led directly to the beer at a point intermediate between the filter
and keg or bunging vessel, or into the 'bunging vessel. It is preferred, however,
to collect the carbonic acid gas under the operation of a vacuum pump B in a
receiver or gasometer E, and thence to convey it through a pipe, F, provided or
not with a pressure valve, F', to the bunging cask G, provided with a pressure
relief valve, G, into which casks the beer is admitted through a valve pipe, s¹,
leading from the filt. C. From the lunging cask, which is provided with suitable
acking means, the beer is conveyed to the kegs, further filtering or charging with
carbonic acid gas being ordinarily unnecessary.
Sometimes the pressare reducing
valve F provided in the pipe F leading from the gasometer to the bunging cask
is utilized, to cause gas first to be admitted to the beer contained in the bunging
cask at high pressure, even as high as thirty pounds, though usually somewhat
less, thereby to cause a complete saturation of the beer, and then reduce the
admitted pressure by manipulating the pressure reducing valve F', and by opening
the pressure relief valve G', set at the desired inherent pressure of the finished
product, causing gradual reduction of the pressure in the beer contained in the
bunging cask without materially changing its saturated condition, until the pressure
has been reduced to the desired pressure in the ultimate product, ordinarily about
five to seven pounds. Instead of using a pressure reducing valve the
maintenance of pressure up to the maximum amount in the beer contained in the
bunging cask may be produced by manipulation of the pressure relief valve G in
the ordinary manner, setting it first at the maximum pressure of, say twenty-five
to thirty pounds, or less, and then gradually reducing it to the minimum pressure
of say five to seven pounds. It is deemed practicable to admit the gas to the
bunging cask G before admitting the beer thereto, but in practice the operation
first described is preferred.
The modified mode of operation illustrated in Figure 2 permits the charging of
beer, after fermentation and filtration, with carbonic acid gas obtained from
fermentation either in the bunging cask, as illustrated in Figure 1, the gas being
retained in a gasometer or receiver before its admission to the cask, or at a
point intermediate between the filter C and the bunging cask G while the beverage
is passing from one to the other, the charging gas being obtained from the
gasometer E, or directly from the pipe conveying the gas from the fermenting
vessels. The apparatus includes an atomizing and charging vessel, H, of any con-
venient construction, and preferably provided with a pressure relief valve, H¹, into
the lower part of which vessel leads a valve pipe, r, from the filter C, said pipe r
terminating within the vessel H in a rose or other convenient atomizing means ».
Into the lower part of the vessel H leads a pipe, p, provided with a cock, p',
and connecting with the pipe leading from the pump B to the gasometer.
The pipe is provided with a cock, t, at a point between the connection pl
and the gasometer.
A. pipe, o, provided with a cock, o', which may be of the
form of a pressure reducing valve similar to the valve F, Figure 1, leads from
the gasometer to the pipe p at a point between the cock p therein and the
connection with the vessel H. From this construction it will be seen that if the
cock p' be closed and the cocks t³ and o' be open gas from the gasometer will be.
caused to enter the vessel H at such pressure as may be desired and thoroughly.
saturate the beer introduced in the form of a spray during its movement from
the filter to the keg or bunging cask. On the other hand if the cocks o' and ³
be closed, and the cock open, gas obtained from fermentation and forced onward

page_text: by the action of the pump B may in a similar manner be introduced into the
vessel H thoroughly to saturate the beverage.
From the atomizing or charging vessel H a valve pipe n leads to the bunging
cask being connected in the usual manner for conveying the beer thereto. From
the bunging cask the usual pipe m leads to the keg. It is preferred to utilize the
branch pipe provided with a cock, ², and leading from the pipen at a point
near the bunging cask G, said pipe n being provided at an intermediate point
between said branch pipe and cask with a valve or cock n³. The pipe n' leads to
a horizontal pipe, 4, having one or more branches to which hose may be connected
leading to the kegs or shipping vessels. The pipe m leading from the bunging
cask may also connect with the pipe 4, as shown in the drawings. With this con-
struction it will be apparent that by closing the valve or cock n in the pipe n, and
by opening the cock, the beer after filtration and saturation in the vessel H may
be led directly to the kegs or shipping vessels; and by closing the cock and
opening the cock the beer may be conveyed into the bunging cask to be
transferred as desired to the kegs or shipping vessels through the pipe m.
Whether the gas be admitted to the bunging cask G directly from the fermenta-
tion vats and pump, or from a gasometer E, it is preferred to introduce it into the
beer contained in the bunging cask through an arrangement of pipes similar to that
employed for introducing it into the main fermentation vat and designated in the
present drawing by the letter D as shown in Fig. 1. It comprises a pipe having
branches and leading into the bottom of the bunging cask, said pipe being
closed at one end and receiving at the other the nozzle end of the gas supplying
pipe F, the nozzle projecting beyond the branch pipe . The effect of this
arrangement is to produce an action similar to the action of a Giffard injector,
creating a suction through the pipe and serving to produce a circulation of the
beer through the pipe D in the direction of the arrows, the beer meantime being
thoroughly saturated with the carbonic acid gas.
While particular stress has been laid in the foregoing description upon the
utilization of the gas obtained from the main and secondary fermentation, it will
be understood that the gas used for charging the beer may be obtained from
other sources, as from any convenient generator; and it is also to be understood
that the gas referred to may be obtained from several fermentation vessels in
operation, while the beer operated upon is obtained from one only of these vessels.
By employing a means for generating gas other than that found in the fermen-
tation vessels it is quite apparent that if from any cause the gas obtained from the
fermentation vessels shall not be sufficient in quantity or pressure to supply the
demand, or if it shall for any reason be desired not to, utilize the gas obtained from
the fermentation vats, the operation of charging may be conducted by utilizing
proper gas generated by the generating apparatus in addition to or in place of the
gas obtained from fermentation. The gasometer E is especially intended not only
to collect and hold gas obtained from the fermentation, but if necessary or desirable
also to receive and hold carbonic acid gas obtained from other sources.
The desirability of filtering the beer before charging with carbonic acid gas is
at once apparent to those skilled in the practice of manufacturing beer, since the
filtration of a still liquid is more easily conducted than the filtration of one charged
with gas; but it should be understood that this invention is not limited to a process
in which the filtration shall precede the charging with gas, as it is quite evident that
the connection shown for introducing the carbonic acid gas into the beverage may
precede the filter, involving a mere transposition of these parts, and the usual
adjuncts to the filter employed in the filtration of charged liquids.
By means of the process above described the time employed in the manufacture
of beer is greatly reduced and all the disadvantages attending the use of
"kraeusen" and shavings, or either of them, are avoided. The saturation of the
beer to the required degree with carbonic acid gas instead of requiring from five to
twenty days or more, as is the case with the kraeusen
process, may be effected
much more satisfactorily with the process above described in less than three days,

page_text: and under the most favorable conditions in a few hours, leaving the product in the
same condition as to purity and quality as that at which it leaves the storage casks,.
or even in better condition, everything which could in any way tend to produce a
deterioration of the beverage being wholly avoided. The saving and utilization of
carbonic acid gas generated during fermentation of the beer forms one of the
desirable features of the process, since it contributes not merely to the economy of
the process, but also in a material degree to the preservation of a pure condition in
the atmosphere of the brewery.
Having now particularly described and ascertained the nature of the said
invention, as communicated to me by my foreign correspondents, and in what
manner the same is to be performed, I declare that what I claim is :-
1. The process of treating beer after fermentation for the purpose of clarifying.
it and saturating it with the requisite quantity of carbonic acid gas to fit it for the
market, which consists in passing it through a filtering medium to remove the yeast.
and suspended impurities, and injecting into it free carbonic acid gas under pressure,.
substantially as described.
2. The process of treating beer after the completion of fermentation, for the
purpose of clarifying it and charging it with the requisite quantity of carbonic
acid gas, which consists in filtering the beverage after its removal from the
fermenting vessel, and thereupon charging it with carbonic acid gas in quantity
sufficient to give to the finished beverage the requisite inherent pressure, substan-
tially as described.
3. The process of treating beer after fermenting for the purpose of clarifying and
charging it with the requisite quantity of carbonic acid gas, which consists in
abstracting from the fermenting vessels gaseous products of fermentation, passing
the beer after it leaves the fermenting vessels through a filtering medium and
charging the beer after it leaves the filtering medium with carbonic acid gas by
introducing into it the gaseous products of fermentation obtained from the
fermenting vat, substantially as described.
4. The process of treating beer after fermenting for the purpose of clarifying it.
and charging it with the requisite quantity of carbonic acid gas, which consists in
abstracting from the fermenting vat gaseous products of fermentation, passing the
beer after it leaves the fermenting vat through a filtering medium and introducing
into the beer the gaseous products of fermentation obtained in the manner
described, substantially as set forth.
5. The process of treating beer after fermenting for the purpose of charging it
with the requisite quantity of carbonic acid gas, which consists in introducing into.
the beer while in transit and moving from the fermenting vessels to the ultimate
receptacle, carbonic acid gas under pressure, substantially as described.
6. The process of treating beer after fermenting for the purpose of clarifying it.
and charging it with the requisite quantity of carbonic acid gas, which consists in
passing the beer while in transit from the fermenting vessels through a filtering.
medium and thereupon while in motion and before reaching the ultimate receptacle
introducing therein carbonic acid gas under pressure, substantially as described.
7. The process of treating beer after fermenting for the purpose of charging it.
with the requisite quantity of carbonic acid gas, which consists in confining the
beverage in a suitable receptacle, introducing into said receptacle and into the beer
contained therein carbonic acid gas under high pressure, and thereupon relieving
the pressure to permit the same to fall to the desired inherent pressure in the
finished product, substantially as described.
8. The process of treating beer after fermenting for the purpose of charging it
with the requisite quantity of carbonic acid gas, which consists in confining the
beer while in transit from the fermenting vessels in a suitable receptacle, intro-
ducing carbonic acid gas into said receptacle and into the beer contained therein,
and causing a circulation of the beer by the action of the introduced gas, thereby
more thoroughly saturating the beer with gas, substantially as described.

page_text: 9. The process of treating beer after fermenting for the purpose of clarifying it
and charging it with the requisite quantity of carbonic acid gas, which consists in
passing the beer through a filtering medium, collecting and storing the gaseous
products of fermentation, conveying the beer to a receptacle, introducing into said
receptacle and into the beer contained therein the stored gaseous products of
fermentation under high pressure, and thereupon relieving the pressure to reduce
the same to the desired inherent pressure in the finished product, substantially as
described.
Dated this 9th day of March 1892.
ALFRED J. BOULT,
Chartered Patent Agent.