IMPROVEMENTS IN MASH TUNS, AND IN APPARATUS TO BE EMPLOYED THEREWITH, WHICH APPARATUS IS ALSO APPLICABLE TO THE HEATING AND KEEPING UP OF A CONTINUOUS CIRCULATION OF LIQUIDS IN ANY VESSEL TO WHICH IT MAY BE CONNECTED
Year: 1857

page_text: (This Invention received Provisional Protection, but notice to proceed with the
application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by John Grist at the Office of the
Commissioners of Patents, with his Petition, on the 17th August 1857.
I, JOHN GRIST, of Islington, in the County of Middlesex, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN MASH
TUNS, AND IN APPARATUS TO BE EMPLOYED THEREWITH, WHICH APPARATUS IS ALSO
APPLICABLE TO THE HEATING AND KEEPING UP OF A CONTINUOUS CIRCULATION OF
LIQUIDS IN ANY VESSEL TO WHICH IT MAY BE CONNECTED," to be as follows:-
My improvements in mash tuns consist, first, in dividing the interior
thereof by perforated vessels or chambers, whereby the grains can be readily
taken from the tun, a crane or other suitable apparatus being employed to
draw up each chamber out of the tun. For the sake of discharging the
grains from the chambers, I fit them with a hinged or sliding bottom or side.
I make the tun steam-tight to prevent the essence of the mash escaping,
and thereby increase the strength of the wort; and, while mashing, I cause (by
suitable machinery) the perforated chambers, together or alternately, to rise up
out of the wort, and descend into it again frequently, whereby the malt or
grain becomes resaturated each time it descends into the wort. Thus the malt
or grain is frequently partially drained and resaturated, which has the effect of
drawing the extract or strength from the malt or grain. While the operation or
mashing is going on, I supply a little steam to the upper part of the tun, to
prevent the malt cooling or reducing the temperature of the wort; but where

page_text: the brewer brews variable quantities (sometimes large and sometimes small
quantities), I make small tuns and place them in series or rows (one behind
the other), the last in the series being placed higher than that immediately in
front of it, and I so connect them by pipes that the wort in the back tuns
shall run into that in front, the whole of the tuns being fitted with the afore-
said cylinders, the wort would circulate through the whole of the tuns, or as
many of them as may be in use. A brewer could thus prepare his mash tuns
so as to mash 10 or 100 quarters of malt, according as he may require.
And second, in fitting the tuns with the heating and circulating apparatus to
be presently described. My apparatus for heating and keeping up a continuous
circulation of liquids in mash tuns and other vessels, consists of a cylinder fitted
with tubes. The liquid way through the tubes is connected by a pipe leading
from each end of the cylinder to the upper part of the mash tun or vessel just
below the level of the liquid contained therein; a stop-cock is fitted to the upper
part of each pipe outside the tun or vessel; branch pipes also fitted with stop-
cocks lead into the pipes, and these branch pipes connect the liquid contents of
the tun or vessel just below the perforated false bottom, when such false bottom
is employed, or the contents of the tun close to the bottom thereof, with the
pipes leading into the tubes in the cylinder. There is a clear passage for
liquid through the tubes fitted in the cylinder. It is essential for the proper
working of the apparatus, that the cylinder or rather the tubes forming the
liquid way through the same should be placed at an angle with a horizontal
line. Steam or hot air is admitted into the cylinder, and a valve for the
escape of water from condensed steam or for air beyond a certain pressure is
fitted thereto to allow of the water of condensation or the air being discharged
outside of the cylinder.
The operation is as follows:-Supposing the mash tun or vessel to be
charged, communication with the top of the tun on one side is shut off by the
stop-cock on the upper part of one of the pipes leading to the tubes in the
cylinder, and the cock in the branch pipe from the same side of the tun is
opened; on the contrary the cock on the opposite branch pipe is closed, and
that on the opposite pipe leading into the top of the tun is opened. Steam
being now admitted into the cylinder will raise the temperature of the liquid
*contents of the tubes fitted therein, which becoming of less specific gravity
than the colder contents of the tun, will ascend through the open communi-
cation into the top of the tun, the contents of the tun will also flow. out
through the branch pipe, communicating from the bottom of the tun with the
opposite end of the cylinder to that from which the liquid ascended, and so on
Econtinuously as long as the temperature of the steam is kept in excess of that

page_text: of the contents of the tun. By reversing the cocks the liquid may be drawn
from the top, passed through the liquid way in the cylinder, and made to enter
the bottom of the tun; or, by setting the cocks to suit the circulation
desired, the liquid may be drawn from the top or bottom of the tun on one
side, passed through the liquid way in the cylinder, and delivered into the top
or bottom of the tun on the opposite side. The heating and circulating effects
are in every case due to the increased temperature generated in the cylinder
by steam, hot air, or heated gases admitted or forced into it. I find, however,
by experiment, that heating alone would be injurious, inasmuch as the wort
in the tun would, by the aforesaid process be raised to a higher temperature
than required or practical with brewing, and I do not seek to secure the
employment of one such cylinder only; but this part of my Invention
consists in the employment of two such cylinders, one being supplied with
cold water for the purpose of lowering the temperature of the wort while it is
passing through it on its way to and before entering the heating cylinder. By
thus cooling and heating the wort in the cylinders, it can be kept at the
required temperature in the tun, and a constant circulation produced. By
supplying water to one cylinder and steam to the other, the wort would be
caused to pass out at the top and in at the bottom of the tun, and by changing
the water and steam to the cylinders, that is to say, by sending steam into
that which had contained water, and water into that which contained steam,
a reverse circulation would take place, the wort would pass out at the bottom
and in at the top of the tun.