Year: 1887

page_text: We HERMANN FREIHERR VON KONITZ of Berlin and JOSEF ZUNTZ of Bonn on the
Rhine both of the Kingdom of Prussia, 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 :-
This Invention relates to a process for the production of a concentrated extract of
coffee which when diluted with a sufficient quantity of boiling water forms a beverage
possessing all the properties of freshly prepared coffee. This process is the result of
a careful study of the volatile and non volatile constituents of roasted coffee.
It is well known that after continued boiling an infusion of coffee loses almost the
whole of its aroma and is converted into a bitter liquid with a burnt flavour. By
collecting and condensing the vapour which it evolves a turbid fluid with a mixed
odour is obtained. The agreeable part of the odour arises from the specific or true
aroma of the coffee berry and the unpleasant part from the basic products and
carburetted hydrogen. We have discovered that the aromatic portion can be readily
separated by distillation from the other portion being more casily volatilised than the
latter. Consequently by stopping the distillation process after a given period the
purely aromatic part can be obtained as a concentrated and separate product. The
separation is facilitated by slightly acidulating the condensed liquid with a non volatile
acid preferably sulphuric acid and conducting the distillation in vacuo. Under these
conditions almost the whole of the pure aromatic principle goes over in the first,
quarter of the distillate obtained by distilling the whole of the liquid whilst the
objectionable substances are partly carried over at a later period and partly remain in
the form of residue.
If on the other hand the extract obtained by a regular or systematic exhaustion of
roasted coffee be evaporated or boiled down (the vapour being collected for condensation
and separation of the aromatic parts) firstly over an open fire and afterwards in vacuo
until it acquires a syrupy consistency a non aromatic and intensely bitter product is
obtained which when diluted with boiling water possesses some agreeable properties
approaching those of freshly prepared coffee and is free in other respects from all
objectionable flavours.

page_text: When this bitter extract is mixed and digested with the fraction or product of
distillation containing the aromatic principles separated as hereinbefore described a
clear and fluid syrup is obtained which dissolves readily in boiling water. This
solution is an admirable imitation of coffee freshly prepared from the berry and is even
superior to the latter owing to the absence of all substances prejudicial to the aroma.
The syrup obtained as herein before described forms a new extract of coffee and
differs essentially by its powerful and pure aroma from all the coffee extracts
heretofore manufactured which consist of more or less concentrated bitter extracts
without the aroma and other essential principles of the berry.
Having now particularly described and ascertained the nature of this Invention and
in what manner the same is to be performed we declare that what we claim is :-
First. In the manufacture of extract of coffee producing a concentrated decoction
containing the extractible bitter and non volatile constituents of roasted coffee and at
the same time isolating or separating the volatile and aromatic portion carried off with
the vapours evolved from the said decoction substantially as hereinbefore described.
Second. In the manufacture of extract of coffee separating the principles or
elements containing the specific or essential aroma of the coffee from the objectionable
substances combined therewith by a fractional distillation of the liquid resulting from
the condensation of the vapours produced in the evaporation or boiling down of a
decoction of coffee with or without the employment of a non volatile acid or a vacuum
substantially as hereinbefore described.
Third. The production of a concentrated extract of coffee by digesting the bitter and
non aromatic products or decoction obtained as herein before explained by an evaporating
or boiling down process with the product containing the concentrated and purified
aromatic elements separated from the condensed vapours evolved from such decoction
substantially as hereinbefore described.
J. HENRY JOHNSON,
47, Lincoln's Inn Fields, London, W.C.,
Agent.