Improved Process for Treating Beer and Making it Keep Permanently in Good Condition.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improved Process for Treating Beer and Making it Keep Permanently
in Good Condition.
We, JOHANN FRANZ HUGO GRONWALD, Apothecary, of 33 Kaiser Strasse S,
and EMIL HEINRICH CONRAD OEHLMANN, Engineer, of 70 Dresdener Strasse S, both
of Berlin in the German Empire 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 :-—
The processes hitherto known for pasteurizing beer secure only its durability by
destroying the vitality of the firmenting organisms, but not the clearness appropriate
to fresh beer nor its aromatic taste and warming and reviving effects, so that the
employment of said processes in practice has hitherto remained very restricted.
Our invention consists in a novel or improved process.the employment of which not
only renders the beer durable, but keeps it clear and preserves the particular aromatic
taste of every kind of beer resulting from hops or other flavourings or ingredients
admissable in brewing and retains in it all the volatile or soluble ingredients detern.ining
its composition, taste and value. By the same process a muddy beer unfit for use
can be rendered clear again and fit for use.
Our improved process is based upon the following considerations: When beer is
heated according to the previously used pasteurizing process, the volatile ingredients,
that is to say its alcohol, essential oils and partly the rosins of the hops are either
entirely or partially lost. Even when a hermetically sealable vessel is used for
pasteurizing the said ingredients will become separated from the liquid, and on cooling
the vessel become condensed again in this way that the alcohol being the most readily
condensed ingredient, will collect on the top of the beer while the essential oils and
volatile rosins of the hops will be deposited later on upon the surfaces of the vessel in
its upper part. Independently of the circumstance that it is practically impossible
to retain easily volatilised aromatic substances without loss even with the best sealing
arrangements, it is well known that when aromatic volatile rosins and essential oils
have become separated in a concentrated form from their solutions, they cannot be
diffused again in them in the same minute division nor with the same effect upon the
taste. But it is different when a substance is added to them which can dissolve them
and readily absorb aromatic essences.
This done by our improved process, which consists in first distilling the beer and
thereby obtaining separately the alcohol contained in it and dissolved in the alcohol
the aromatic ingredients of the beer, consisting mainly of the essential oils and the
partly volatile rosins of the hops, which are added again to the beer after it has been
subsequently pasteurized and cleared and cooled. Our process therefore consists
essentially in collecting by means of distillation all volatile ingredients of the beer,
which are entirely or partially lost by the previous pasteurizing processes, and to add
them again to the remaining liquid after it has been pasteurized, cleared or fined and
cooled, finally, filtering and impregnating the same with carbonic acid gas. The beer
thus treated will be equal to other lager beer in aromatic taste and warming or
reviving qualities, as it contains its original quantity of alcohol, and will be preferable
to the usual young beer tapped in summer, as the ferments, producing disagreeable
effects, and stomach disorders, are removed by this process. The presence of alcohol
and the volatile ingredients of hops further insure the permanent clearness of the
beer.
The improved process herein before described is carried out in the following manner:
The beer to be treated is placed into a still pan or retort having a double envelope or
jacket and fitted with a cover or head, the latter of which communicates through a
pipe with a condenser, consisting of a coiled pipe or worm or its equivalent placed in
a vessel filled with cold water or arranged in any other suitable known manner. By

page_text: admitting steam to the jacket, which may be filled partly or entirely with water, the beer
is slowly heated, the temperature being gradually increased to about 180 degrees centi-
grade. The alcohol is thereby distilled off in the form of vapour with the aroma, consisting
of essential oils, volatile rosins of the hops and other aromatic substances contained
in the beer, bound to or mixed with it, and is condensed in the worm or its equivalent
and the liquid drawn off through a tap into a receiver. In this all the ingredients
imparting to the beer its peculiar aromatic taste and warming and reviving effects or
characteristic properties will be found combined.
The remnant left in the still pan, after this distillation, in which the ferments have
been killed and separated by the heat, after having been cleared or fined with albumeri
or other ordinarily used means, is cooled by circulating cold water or refrigerated air
through the jacket of the still pan to 20 to 25 degrees C. and is then thoroughly
mixed with the previously obtained distilled liquor. The mixture is further thoroughly
cooled to 6 to 10 degrees C., in order to obtain a complete separation of the ferments
rendered unsoluble and other organic substances and is then filtered. The beer
treated in this manner has lost its natural carbonic acid and is reimpregnated
artificially in any suitable ordinary manner with carbonic acid in the same quantity as
is contained after fermentation in good beer ripe for drinking. The beer treated in the
manner hereinbefore described can then be filled into barrels or bottles. It is perfectly
clear, keeps permanently and possesses the same qualities and agreeable taste as good
lager beer ripe for drinking and freshly drawn from the barrel.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is,
Firstly, the process for treating beer and making it keep permanently while
retaining all the qualities of lager beer ripe for drinking substantially as herein before
described;
Secondly, treating or preparing beer by separating from the same by means of
distillation the alcohol and volatile aromatic ingredients contained therein and remixing
the distilled product with the remnant after fining and cooling the latter, filtering the
mixture and impregnating it with carbonic acid substantially as hereinbefore described
and for the purpose set forth.
Dated this 30th day of November 1889.

page_text: A clerical error in the original Specification having been amended by the
Patentee, with the consent of the Comptroller, the printed Specification will now read
as shown below
-