Note: Descriptions are shown in the official language in which they were submitted.
--1--
~THOD AND APPARATUS ~F BREWING
Backqround of the Invention
In brew kettle operation, heating of the wort
causes coagulation of proteins, sterilization of the
~ort and the destruction of enzymes, extraction of
hops and evaporation of excess water to provide a gen-
eral change of the wort through boiling. The evapora-
tion rate, temperature and circulation of wort in the
brew kettle are important factors in the effective co-
1~ ag~lation of protein as well as hop extraction and hopcharacter.
In the past, "fire brewing" has been used to
impaxt improved flavor characteristics to the beer. In
traditional fire brewing, the wort is boiled in small
copper kettles thatare subjected to direct oil or gas
firing. The direct firing of the wort in the copper
kettles is believed to effect the carmelization and
improve the flavor of the beer.
It is also known to circulate boiling wort
~a through external heat exchangers and return the wort to
the brew kettle through center tube spreaders in order
to obtain more efficient mixing and energy savings. In
a system of this type, known as Kalandria, the wort is
passed through stainless steel tubes in an external
~S heat exchanger in heat transfer relation to steam, and
tl~e ~ort, having been heated several degrees, is then
returned to the brew kettle and is discharged through
a center tube above the level of wort in the kettle.
Summary of the Invention
3~ The invention is directed to an improved
process and apparatus for brewing which achieves the
effect of fire brewing as used in the past. In accor-
dance with the invention, boiling wort from the brew
kettle is continuously circulated through an external
~L2~72~
heat exchanger and is discharged back to the brew
kettle at a location beneath the level of wort in the
kettle.
The heat exchanger includes a heat exchange
section having a copper heat exchange coil through
which the wort is circulated. A fuel, such as natural
gas, is combusted in the reactor section of the heat
exchan~er, and the gases of co-l~bustion are dis-
charged at high velocity over the copper coil to heat
1~ the circulating wort to a temperature in the range of
220~ to 2~F. A control valve in the recirculation
~ystem is utilized to provide the desired back pressure
in the recirculating line and the residence time of the
wort in the heat exchange coil.
lS The direct heating of the wort in the copper
coils provides a fire brewing treatment that improves
the flavor characteristics of the beer.
Description of the ~rawings
Fig. 1 is a schematic representation of the
2a brewing process of the invention; and
Fig. 2 is a longitudinal section of the ex-
ternal heat exchanger.
Description of the Illustrated Embodiment
Fig. 1 is a schematic representation of the
~5 brewing apparatus and process of the invention, and
includes a conventional brew kettle 1 to contain wort.
A series of percolators 2 are mounted in the brew
kettle and served in the conventional manner to agitate
and circulate the wort in the desired pattern.
~ Located in the lower end of brew kettle 1 is
a discharge line 3, and valves 4 and S are connected in
line 3. The lower end of line 3 is connected to the
suction side of a pump 6 which is driven by motor 7 so
that operation of pump 6, when valves 4 and 5 are open,
will drain wort from the brew kettle.
2~
-3
In accordance with the invention, the boil
ing wort is circulated through a heat exchanger 8
which is located outside of the brew kett:le. Conduit
9 connects discharge line 3 to the inlet side of a
pump 10 driven by motor 11, while the discharge side
of-pump 10 is connected through line 12 to one end
of a copper coil 13 disposed in the heat exchanger
section 14 of heat exchanger 8. As best shown in Fig.
2, coil 13 has a spiral configuration and the tubing
of the coil has a relatively large diameter in the
neighborhood of 4 inches. The large diameter tubing
permits the free flow of hops and other materials con-
tained in the wort.
Coil 13 is contained within an outer housing
15 and the upper end of the coil 13 is connected
through a line 16 to brew kettle 1. Mounted in line
16 is a control valve 17, and by adjustment of valve
17 the flow rate of wort through the heat exchange
coil 13 can be varied as desired. Adjustment of valve
1~ regulates the back pressure of the circulating wort
and controls the residence time of the wort within the
coil 13 to obtain the proper heating of the wort.
Conduit 16 extends through an opening in
the sidewall of brew kettle and terminates in an upward-
ly extending discharge pipe 18 having an open upper end.A deflector plate 19 is mounted in space d relation to
the upper end of pipe 18 and both the upper end of
pipe 18 and the deflector 19 are located beneath the
level of the wort in brew kettle l. The wort being
returned to brew kettle 1 is discharged in the brew
kettle upwardly in the same general direction as the
percolation to thereby increase the efficiency of the
mixing of the recirculating wort in the kettle.
~2~
The wort passing through the coil 13 is
heated by combustion gases that are generate~
in reactor section 20 of heat exchanger ~. As shown
in Fig. 2, reactor section 20 includes an outer
casing 21 and an inner casing 22 which is spaced
radially inward of casing 21 to provide an annular
space 23 between the casings. Air for combustion pur-
poses is introduced tangentially into the lower end
of the annular space 23 through tangential inlet 24.
The combustion air is supplied to the inlet by a suit-
able blower, not shown.
The combustion air circulates upwardly within
space 23 to the upper end of the reactor section 20
where it is mixed with gas introduced into the reactor
lS section through inlet 25. As shown in Fig. 2, both a
fuel gas line 26 and a pilot gas line 27 are connected
to inlet 25. The air-fuel mixture is ignited by a con-
ventional ignitor 28 which is mounted in the upper end
of reactor section 20.
2~ The air passing through the annular space 23
in rotational flow generates a vortex at the point of
fuel injection and allows for the use of low pressure
~els. Rapid mixing of fuel and air at the ignition
~oint results from the vortex.
~5 The combustion is completed within reactor
section 20 without any flame extension into the heat
~xchanger section 14. The gases of combustion exit
~rom t:le reactor at a hig:l velocity of approximately
300 feet per minute and are discharged through a ve~turi
3d or nozzle 29 into the central portion of heat exchanger
section 14 within the coil 13. The hot gases are
then deflected upwardly at the bottom of the heat ex-
changer section and flow back up on outside of the coil
13 to provide a uniform heat transmission. The
gases are discharged from the heat exchanger through
the outlet 30.
~7~
In operation, when the temperature of the
wort reaches 212F in the brew kettle, valve 4 is
open and pump 10 is operated to circulate wort through
the heat exchanger 8. The flow rate is controlled by
operation of control valve 17 to provide a preferred
~low o about 425 barrels per hour at 15 psig. This
r~sults in the wort being heated to a temperature in
th~ range of 220F to 240F, and preferably about 230F.
The returni~g wort is discha-ged from pipe 18 in an up-
la ward direction in the brew kettle in the direction ofpercolation, and partial flashing of the wort into
steam will occur as it is reintroduced into the brew
kettle.
The direct heating of the wortin the copper
coils 13 of heat exchanger 8 provides a fire brewing
o~ the wort which imparts improved flavor character-
istics to the beer.
