IMPROVEMENTS IN BREWING MALT LIQUORS
Year: 1861

page_text: PROVISIONAL SPECIFICATION left by Henry Medlock at the Office of
the Commissioners. of Patents, with his Petition, on the 1st February
1861..
I, HENRY MEDLOCK, of No. 20, Great Marlborough Street, in the City of
Westminster, Analytical Chemist, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN BREWING MALT LIQUORS," to be as follows:-
My Invention consists in the peculiar mode of treating the hops in brewing
malt. liquors herein-after described, whereby the formation from the hops of
substances injurious to the beer is prevented, and the aromatic volatile product
of the hops, and the resinous and bitter substances in the hops are more readily
extracted.
To make the nature of my Invention clear, I will first state what takes
place when hops are used in the ordinary way in brewing malt liquors, that is
to say, when the hops are boiled for a certain time with the wort. As the
temperature of the wort rises, a volatile aromatic substance is produced, which
dissolves in the wort, but which by the increase of the temperature is in a
great measure dissipated. The wort being continued at the boiling point for
some time certain substances disagreeable to the taste and injurious to the
malt liquor are formed from the albuminous matter and resinous matter in the
hops, and when the temperature arrives at or near the boiling point of water,
the albuminous matter coagulates and impedes the extraction of the valuable
products and constituents of the hops. It is, however, necessary in order to

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separate the gluten of the malt from the wort to boil the latter with the
resinous matter of the hop. The resinous matter is slightly acid, and unites
with the gluten of the malt, forming a compound insoluble in cold water,
consequently when the wort is cooled, part of this compound sinks to the
bottom, and the remainder is expelled during fermentation. For the purpose
of using the hops to the best advantage in brewing malt liquors, three things
are necessary; 1st, that the volatile aromatic matter should not be heated to
such a temperature as to volatilize it; 2nd, that the resinous and albuminous
matters should never be boiled while in contact; 3rd, that the resinous matter
should be boiled with the wort. I accomplish this in the following way :-
I soak the hops in water, the temperature of which must not be high enough
to coagulate the albuminous matter, 160° of Fahrenheit will generally be found
to be the maximum temperature which can be safely used. I prefer a heat
from about 120° to 150° of Fahrenheit. During this process, the volatile
aromatic substance is produced and dissolves in the water. The albuminous
matter is also dissolved, the heat not being sufficient to coagulate it. I then
strain the water from the hops, removing by this means the volatile aromatic
substance and albuminous matter; after the hops have been so treated I boil
them with the wort in the usual way, by which I effect the combination of the
resinous matter with the gluten of the malt, the absence of the albuminous
matter greatly facilitating the extraction of the former, and of the bitter flavour
of the hops. The combination of the resinous matter of the hops and the
gluten of the malt subsides on cooling the wort, and may be separated from it
in the usual way. When the wort has sufficiently cooled, and before or shortly
after the fermentation begins, I add to it the cooled solution of the volatile
aromatic substance, which with the albuminous matter has been extracted as
above described.