IMPROVEMENTS IN THE TREATMENT OF HOPS IN BREWING
Year: 1878

page_text: LETTERS PATENT to Frederick Gretton, of Burton-on-Trent, in the County of
Stafford, for the Invention of "IMPROVEMENTS IN THE TREATMENT OF HOPS
IN BREWING."
Sealed the 21st March 1879, and dated the 3rd October 1878.
PROVISIONAL SPECIFICATION left by the said Frederick Gretton at the
Office of the Commissioners of Patents on the 3rd October 1878.
FREDERICK GRETTON, of Burton-on-Trent, in the County of Stafford.
PROVEMENTS IN THE TREATMENT OF HOPS IN BREWING."
"
"IM-
This Invention has for its object improvements in the treatment of hops in
brewing.
At the present time it is usual after boiling the hops with the wort to drain them
in the hop back and afterwards to expose them to hydraulic or other pressure, they
are pressed as dry as possible, and the liquor pressed out is mixed with the rest of
the wort. After being pressed the hops are of no further use to the brewer and
are sent away as spent hops. Now I have discovered that the process above
described fails to extract from the hops all of the valuable principles which they
contain; but that on the contrary by a suitable and novel treatment which I have
devised so much more valuable matter may be extracted that a very important
saving in hops is obtained. This process consists in sparging the hops or sprinkling
them with water, and draining them repeatedly either in the hop back, or by
preference after transferring them to another deeper vessel provided with a
perforated false bottom or strainer. The hops are kept as open as possible, so that
the air as well as the moisture may permeate amongst them. The liquor which
drains from the hops is mixed with the wort. After repeated spargings the hops
are discharged; they then contain nothing more of value which the brewer can
extract; the operation of pressing is unnecessary.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick Gretton in the Great Seal Patent Office on the 3rd April
1879.
FREDERICK GRETTON, of Burton-on-Trent, in the County of Stafford.
PROVEMENTS IN THE TREATMENT OF HOPS IN BREWING."
"IM-
This Invention has for its object improvements in the treatment of hops in
brewing.
At the present time it is for the most part usual after boiling the hops with the
wort to drain them in the hop back and afterwards to expose them to hydraulic or
other pressure; they are pressed as dry as possible, and the liquor pressed out is
mixed with the rest of the wort. After being pressed the hops are of no further
use to the brewer and are sent away as spent hops. To obviate the necessity of
pressing the hops it has been proposed to submit them to successive spargings of
wort, and a Patent for thus treating spent hops was granted to Horace Tabberer
Brown in the year 1875, No. 1806.
Now I have discovered that the wort and valuable principles contained in the
spent hops can be extracted from them better and at less cost by at once sparging
or sprinkling them repeatedly with water, and draining them either whilst they
remain in the hop back, or after transferring them to another and it may be a
deeper vessel provided with a perforated false bottom or strainer. The hops should
be kept as open as possible so that the water may permeate amongst them. The
liquor which drains from the hops may be mixed with the wort. After repeated
spargings the hops are discharged; they then contain nothing more of value which
the brewer can extract. By treating spent hops in the above manner more valuable
matter can be extracted from them and at less cost than by either of the previous
methods above mentioned, and a very important saving of wort and hops is
effected.
Having thus described the nature of my Invention I will proceed to describe
more fully the manner of performing the same.
When the sparging operation is to be carried out with the hops remaining in the
hop back I provide above the hop back sparging apparatus constructed by preference
in the manner shewn at Figures 1, 2, and 3 of the Drawings hereunto annexed.
Figure 1 is a plan view of a hop back and sparging apparatus; Figure 2 is a
vertical transverse section; and Figure 3, a vertical longitudinal section of the
same. A is the hop back; the perforated false bottom of this hop back is not
shewn in the Drawing. Above the hop back are two spargers, each consisting of a
series of horizontal perforated tubes B branching out from a tube C which is carried
at its centre by a vertical telescopic tube D, through which water can be supplied
to the perforated tubes of the sparger. E, E, are weights to balance the weight of
the lower portion of the sparger, as shown. By having the tubes D telescopic the
lower portion of the sparger can be raised up so as to be out of the way when not
in use..
After a charge of spent hops has been collected in the hop back and the greater
part of the wort allowed to drain off from the hops in the ordinary manner, the
hops lie evenly over the perforated false bottom of the hop back, and the spargers
are lowered to the position shewn at Figures 2 and 3. Water, by preference at a
temperature, say, of about 180° Fahrenheit, is then supplied to the tube D (the
hotter the water the better) and trickles down through the perforations in the
tube B in a gentle shower on to the hops, and draining away downwards through
the hops carries down with it the remainder of the wort and completes the extraction
of all valuable matters from them. This sparging or sprinkling of the hops with
water may either be carried on continuously or intermittently, as desired. The
amount of water thus sprinkled over a given quantity of hops and the time
occupied by the sprinkling operation may be varied. In practice I use about one
measure of water to every seven of hops.

page_text: In place of the hops being treated in the manner above described, whilst they
remain in the hop back they may, as before stated, be removed into other vessels to
be treated.
For this purpose a circular vat, say of about 8 feet in diameter and 5 feet in
depth, may be set up in front of each hop back, as shewn at Figures 6 and 7, so
that the hops inay readily be shovelled from the hop back into these vats. The
size of the vat will however vary according to the quantity of hops required to be
treated at any one time. Each vat is provided with a perforated false bottom to
allow liquid to drain away freely from the hops.
Above each circular vat is a sparging apparatus, which in this case may be a
revolving sparger caused to revolve by the passage of water from the perforations
in its arms, as is well understood. The sparger can also be arranged to be raised or
lowered. Figure 4 shows a side elevation and Figure 5 a plan view of such a
circular vat with a revolving sparger mounted above it. The tube by which the
sparger is suspended is made telescopic, and its lower moveable portion is counter-
balanced, as shown, to allow the sparger to be raised up to be out of the way
whenever required. When the sparging operation is conducted according to the
directions above given it will be found that with hops that have been boiled with
wort for brewing a strong pale ale the wort drained off from the hops will be of a
strength of about 9 lbs. per barrel, that is, about the strength of ordinary pale ale,
and may be added to the rest of the wort.
Having thus described the nature of my said Invention and the manner of
performing the same, I would have it understood that I claim,—
First. The treatment of spent hops to obtain wort and valuable products from
them, substantially in the manner herein-before described.
Second. The treatment of spent hops to obtain wort and valuable products from
them by sparging water over them whilst they remain in the hop back, substantially
as herein-before described.
Third. The treatment of spent hops to obtain wort and valuable products from
them by removing them from the hop back into vessels provided with perforated
bottoms, and then at once sparging water over them, substantially as herein-before
described.
In witness whereof, I, the said Frederick Gretton, have hereunto set my hand
and seal, this Second day of April, in the year of our Lord One thousand
FREDERICK GRETTON. (L.S.)