Improvements in the Manufacture of Beer.
Year: 1892

page_text: Date of Application, 9th Mar., 1892-Accepted, 23rd Apr., 1892
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Beer.
A communication from THE PEAUDLER 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 perforined to be particularly described and ascertained in and by the
following statement :-
This invention relates to a new process of manufacturing beer, and has for its
object the manufacture of lager-beer, so called, by a process which shall reduce
the ordinary period involved in the manufacture from several months to a few days.
Lager-beer derives its name from the fact that under the common process of
manufacture after mashing, abstracting, boiling, hopping, cooling and fermenting in
the main fermenting-vat, it is retained in storage, ruh, or lager-casks for a period
generally in excess of two months more or less, during which retention in the
storage-cask the secondary or subsidiary fermentation is permitted to proceed to
substantially the absolute completion. The kind of beer thus produced is the kind
to which the present invention relates; but, as before stated, the purpose of the
invention is to bring about the complete manufacture of the beer in a brief period,
not exceeding one month.
The ordinary procedure heretofore practised in the manufacture of lager-beer
has been the following:
::
The mash having been made and the wort abstracted and boiled, hopped and
cooled, as above stated, is conveyed to a settling-tank, and thence after settling to
the main fermentation-vessel where the yeast is commonly added (though it is
frequently added in the settling-tank and occasionly even as far back as the
receptacle which receives it from the cooler) and after the yeast has taken hold of
the wort, or, as it is termed in the art, after the wort has been pitched with the
yeast, a violent fermentation accompanied by a rapid reproduction of the yeast
takes place with the production of "kraeusen or young beer as evidenced by the
formation of a white curly cap of foam. The main fermentation ordinarily takes about
two weeks. The beer, preferably after skimming, is thereupon transferred to the
lager, ruh, or storage cask (the greater portion of the yeast being left in the main
fermenting-vats) where it is retained until the secondary fermentation has been
completed, which rarely requires less than two months and sometimes requires as
much as five months. The secondary fermentation may, however be conducted in
the fermenting-vats without the transfer to separate ruh or storage-casks, but while
similar to the first, so far as the production of alcohol and carbonic acid gas is
concerned, it differs from the main fermentation is certain recognized particulars,
and brewers are familiar with the line of demarcation between the main or primary
and the subsidiary or secondary fermentation, the distinction between the two being
apparent upon examination of the beer and uniformly identified among brewers by
the terms main and secondary or after fermentation. It has been found by
examination and experiment that the distinction is quite as definite when both the
main and secondary fermentation are conducted in a single vessel as when they are
conducted in separate vessels, the difference being readily noticeable if the beer
after the completion of the main fermentation is permitted to remain in the same
vessel without removal. Brewers, however, do not, if they can avoid it, allow beer
to remain even for a day on the yeast after the first fermentation is complete, and
it is found that the racking off of the beer permits the secondary fermentation, in the

page_text: way of brewing hithereto practised, to continue more satisfactorily and without
contamination from precipitated deleterious elements if such exist.
After the completion of the secondary fermentation it is usual to rack the beer
into shavings or bunging casks where a fining medium, such as isinglass, is intro-
duced, together with young beer called "kraensen" obtained from the main
fermenting vessel, a new fermentation being thus excited generating carbonic acid
gas, and a bunging apparatus being applied to cause this finishing to take place
under a predetermined pressure obtained from the rising carbonic acid gas. The
pressure generally found most desirable is from five to seven pounds.
For the purpose of expediting the manufacture of beer, a vacuum has been
applied to the beer during the stage of secondary fermentation, the vacuum being
employed with a cool atmosphere, always necessary, and being made continuous and
coupled with the abstraction of gaseous products of fermentation as they accumulate
at the top of vessel. By this means, the secondary fermentation is materially
hastened without in any degree interfering with its completion, the period being
reduced to less than ten days, instead of from one to five months as heretofore
required.
The process referred to is explicitly limited to the treatment of beer produced by
lower or bottom fermentation in the stage of secondary fermentation for the purpose
of hastening the aging or ripening of the beer, and the main fermentation may be
conducted in the usual way in open vats, but if it should ever be found practicable
the main fermentation may be conducted in nucno.
So fas as known, it has never heretofore been deemed practicable to conduct the
main fermentation of beer produced by bottom fermentation under a partial or
approximate vacuum.
It is true that it has been heretofore suggested that certain fermented beverages
produced by upper fermentation might, with advantage, have their main fermentation
conducted or begun under a reduced pressure or partial vacuum, (whether or not
this was done with beneficial results does not appear). Undoubtedly, however, in
all cases where the main fermentation of the beverage has been conducted under a
partial vacuum the operation has taken place under conditions of temperature
usually in excess of 60° F. and other conditions entirely incompatible with the
manufacture of lager-beer or beer produced by what is described as lower or bottom
fermentation.
We have found that by observing certain provisions hereinafter set forth, the
main fermentation of lager-beer may be conducted under a partial or approximate
vacuum with beneficial results of a high order, both in the saving of time, labor
and cost and in the quality of the product, and that the present invention may be
used with great advantage in conjunction with the process above referred to.
The present invention consists broadly in retaining the wort pitched with yeast
in a closed vessel and abstracting atmospheric air and gaseous products of ferinen-
tation as they accumulate in the upper part of the vessel, thereby creating a partial
or approximate vacuum, and maintaining the fermenting wort at a certain requisite
temperature, as hereinafter described, until the main fermentation is completed, as
a preliminary to subjecting the beer to an aging or ripening treatment by secondary
fermentation.
It consists further in conducting the main fermentation of the wort under a
partial or approximate vacuum, as fast above set forth, and thereupon and in the
same vessel subjecting it as a continuation of the first operation to the aging or
ripening process aforesaid, and the invention consists further in conducting the
main fermentation of the wort in a closed vessel under proper provisions, as to
temperature hereinafter set forth, abstracting atmospheric air and gaseous products
of fermentation as they accumulate in the upper part of the vessel, thereby
producing a partial or approximate vacuum, and, as hereinafter described, supplying
the fermenting wort with atmospheric air in regulated quantity.
It has been found in practising this invention in the manner above outlined, and
hereinafter more fully pointed out, that the step of racking the beer off the

page_text: sediment obtained in the main fermentation vat according to the practice heretofore
in vogue, is unnecessary, although it may be practised without departing from the
invention. As before stated, the purpose of this racking has been to withdraw the
beer from contact with the sedimentary matter of a character calculated to produce
a deleterious action upon or to contaminate the beverage; but by reason of the
abstraction of atmospheric air and the withdrawal of the accumulated products of
fermentation, such deleterious action by the sedimentary matter is found to be
neutralized or prevented, and the access to the beer undergoing the main fermenta-
tion of deleterious ferments from the surrounding atmosphere, or other external
Sources, is also prevented.
The accompanying drawing represents a closed fermenting vat provided with an
air-pump adapted to abstract from the upper part atmospheric air and gaseous
products of fermentation which accumulate, and provided at its lower end with the
means for introducing, at will, atmospheric air into the fermenting liquid, adapted
also, as a preferred construction, to create an agitation and circulation of
the wort.
In the drawing:
A represents a fermenting vat, of which in the practice of this invention there
may be one or several, and B a vacuum-pump connected to the upper part of the
fermenting yat, or to each of the several fermenting vats where more than one is
employed, since obviously one vacuum pump may be made to serve for a series of
fermenting vats. The base of each fermenting vat should be provided with one or
more controllable air inlets whereby atmospheric air, preferably previously
sterilized by filtration, heat or other suitable sterilizing or purifying process, may
be injected or admitted into the liquid and pass through the same.
The device is represented for injecting or admitting atmospheric air in the form
of a pipe C below the vat having two branches ts entering the base of the vat,
and a pipe D, smaller in diameter than the pipe C, entering the latter and
extending beyond the branch f. The only communication between the air-pipe
introduced and the interior of the pipe is by way of the pipe D. When it
becomes desirable to impregnate the fermenting wort with atmospheric air a valver
in the pipe D is opened, when atmospheric air at normal pressure, or any other
pressure that may be desired, rushes through the pipe D into the pipe C and by
its direction, based upon familiar physical laws, causes a circulation of the wort
and the sediments associated with it through the branches sand and the pipe C in
the direction of the arrow, thus bringing the molecules of wort and the associated
wort successively into contact with the air. This is found in practice to have a
tendency to revivify the yeast causing the fermentation to proceed more rapidly
and effectively. Of course all the introduced air does not take the course of the
arrows but a portion of it proceeds directly upward through the wort to the relief
of the vacuum at the top; and in this way atmospheric air is disseminated
throughout the body of the liquid, the effect of which is to maintain and accelerate
the fermentation. The device illustrated for introducing atmospheric air into the
fermenting wort is to be regarded only as a preferred form, since, obviously, the
atmospheric air may be introduced by other means, such as a single pipe or set of
pipes, or controllable inlets entering the fermenting vat either at the base or else-
where but in practice it will be found desirable to have the several air-inlets,
however they may be located, controlled by means of a valve common to all. It
is contemplated that in the progress of the fermentation atmospheric air will be
introduced into the wort as circumstances require; that is to say if the wort is
found to be fermenting too slowly atmospheric air may be introduced by means of
the device provided for this purpose in sufficient quantity and at a proper tem-
perature to accelerate to the required degree. In the course of fermentation this
necessity may in some cases not arise at all and in others it may arise once or
oftener.
The introduction of air, as above set forth, will often be found advantageous

page_text: during the progress of the secondary fermentation, and when found desirable
during this stage it may be applied in the manner described above.
In carrying out the process the prepared wort is introduced into the fermenting
vat, or series of fermenting vats, represented by A, and through an inlet pipe or
any other suitable inlet pipe, and is either pitched with yeast before the introduc-
or after it.
It is deemed preferable to pitch the wort with yeast before the
introduction, but so far as the process is concerned it is only necessary that the
wort shall be properly pitched with yeast at the time the vacuum is applied.
When the yeast has begun to act upon the wort producing fermentation, or
previously, or even subsequently, the vacuum-pump is set in action withdrawing
the atmosperic air and carbonic acid gas that occupy the space within the vessel
above the liquid or a considerable portion of the same and thereby produces a
partial or approximate vacuum, preferably of about eighteen inches, and by the
action of the pump this vacuum is ordinarily maintained at approximately the
pressure named, though it may vary temporarily. When atmospheric air is
introduced by the means for that purpose above described, the degree of vacuity
may be gradually or temporarily increased or decreased as occasion seems to
demand. This is a matter which will always be more or less within the discretion
and experience of the brewer.
23
Ordinarily in the manufacture of lager-beer the wort is introduced into the
fermenting vat at a temperature of about 41° F. A physical effect of fermentation
is to increase the temperature and as the beer has heretofore been manufactured it
has been necessary for brewers to exercise great caution to prevent an undue rise
of temperature from this cause, since the effect of an undue rise (above say 48° F.)
is hurtful to the product. Where a tendency to rise above the degree mentioned
has been manifested in the wort it has been customary heretofore to counteract it
by extraneous cooling agencies, such for example as the application of what is
technically called a swimmer or attemperator. The temperature of the
fermenting room is usually maintained uniform at about 41° F. ; but the temperature
of the room does not control the temperature of the wort sufficiently, owing to the
inherent heating tendency of fermentation. In the practice of the present process
the brewer is largely relieved from the necessity of observing and controlling the
temperature of the wort, because the process will operate with perfect success even
though the temperature of the wort be several degrees higher than would be
permissible in the ordinary way of brewing. Under all circumstances the
theoretical limit of temperature at which the main fermentation may be successfully
conducted is for the room about 45° F. and for the wort about 550 F.; but under
the ordinary practice the practical limit is several degrees below the theoretical
limit as above expressed. The present process. however, permits the fermentation
to be conducted at substantially the theoretical limit of temperature and even
renders this limit desirable; that is to say when the main fermentation is conducted
according to the present invention, as above set forth, the temperature of the
cellar may be not lower than about 45°, and the temperature of the wort may,
under the influence of fermentation, be permitted to rise as high as 55°, or there-
about, without injury to the product, and under proper precaution even with benefit
to it. If, however, the temperature of the wort is permitted to rise too high
during fermentation, it has been found from experience that the beer is liable to
acquire an undesirable quality due, it is thought, to the fact that the yeast, by
reason of the unduly high temperature tends toward the quality of yeast which is
productive of upper fermentation. Moreover, the tendency of unduly high
temperature in the wort is to develop deleterious ferments, which necessarily, when
the fermentation is conducted in open vessels, having free access to the wort,
operate to injure it. In the present process, however, the vessels being closed to
the external atmosphere and the gaseous products of fermentation being abstracted
as they accumulate, no deleterious ferments are admitted from external sources,
and those already in the wort have their action more or less suspended..

page_text: The present process, therefore, besides its other advantages permits a material
saving in the cost of refrigeration, since the temperature of the fermenting room.
may, without disadvantage and even under some circumstances with advantage to-
the product be maintained several degrees higher than that usually found necessary
and the use of the "swimmer" or attemperator may practically be dispensed with..
The average time required for the main fermentation, as heretofore practised, is
about fourteen days. With the present process the main fermentation may be.
perfected in from six to eight days, and not only this, but comparative tests of beer
manufactured by this process and beer manufactured by the usual process show that
better results are obtained with from six to eight days fermentation in the former
than with fourteen days, or even more, in the latter.
Having now particularly described and ascertained the nature of the said inven-
tion, 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-In the manufacture of beer by bottom or lower fermentation, the process of
conducting the main fermentation under a partial or approximate vacuum, which
consists in confining the wort pitched with yeast in a closed vessel, abstracting from.
above the liquid atmospheric air and the gaseous products of fermentation as they
accumulate, and maintaining the wort at the requisite low temperature during the
progress of fermentation, substantially as described.
2-In the manufacture of beer by bottom or lower fermentation the process of
conducting the main fermentation and subsequently aging or ripening the product
under a partial or approximate vacuum, which consists in confining the wort pitched
with yeast in a closed vessel, abstracting from above the liquid atmospheric air-
and the gaseous products of fermentation as they accumulate, and maintaining the
wort at the requisite low temperature during the progress of fermentation,.
substantially as described.
3-In the manufacture of beer by bottom or lower fermentation the process of
conducting the main fermentation and subsequently aging or ripening the product
under a partial or approximate vacuum, which consists in confining the wort pitched.
with yeast in a closed vessel, abstracting from above the liquid atmospheric air and
the gaseous product of fermentation as they accumulate, maintaining the wort at
the requisite low temperature during the progress of fermentation until the main
fermentation is completed, and then in the same vessel continue the abstraction of
gaseous products of fermentation and atmospheric air, if any, still maintaining the
requisite low temperature in the liquid for aging and ripening the beer, substantially
as described.
3-In the manufacture of beer by bottom or lower fermentation, the process of
conducting the main fermentation under a partial or approximate vacuum, which
consists in confining the wort pitched with yeast in a closed vessel, abstracting from
above the liquid atmospheric air and the gaseous products of fermentation as they
accumulate, maintaining the wort at the requisite low temperature, and introducing
atmospheric air into the body of the wort during the progress of fermentation,
substantially as described.
4 In the manufacture of beer by bottom or lower fermentation the process of
conducting the fermentation under a partial or approximate vacuum, which consists
in confining the beer charged with yeast remaining from the main fermentation in
a closed vessel, abstracting atmospheric air, if any and the gaseous products of
fermentation as they accumulate above the liquid, maintaining the liquid at the
requisite low temperature and introducing into the liquid during the progress of
fermentation atmospheric air, substantially as described.
5-In the manufacture of beer by bottom or lower fermentation the process of
conducting the main fermentation which consists in confining the wort, pitched with
yeast. in a closed vessel, abstracting in whole or in part the atmospheric air and
gaseous products of fermentation from the upper part of the vessel, introducing
atmospheric air into the lower part of the vessel and into the sedimentary matter

page_text: thereby increasing fermentation and producing a circulation of the wort under
the impulse of the introduced air, substantially in the manner and for the purpose
described.
Datod this 0th day of March 1809
ALFRED J. BOULT,
Chartered Patent Agent.

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