CA1036522A - Process and apparatus for producing wort - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Wort is produced from malt and a coarse grain by preparing separate malt and grain grinds, which are continuously mixed and heated in an elongated, vertical reactor, the reactor including an agitator and a plurality of interconnected sections, each section containing cells heated by circulating liquid. The temperature of each section is controlled, to promote the desired reaction between the malt and grain, the temperature rising from the inlet to the outlet end of the reactor. In an alternative embodiment, the course grain is pretreated in another reactor, and fed into a reactor in which the malt is being treated.

Description

~036522 `~ :
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This invention relates -to a hrewiny process for producing wort and to apparatus for carrying out the process.
Several brewing processes for produclng wort are already known, in particular for producing beer. These -processes may be divided in two classes: the first class ;
including brewing processes which employ the so-called "standard" method and particularly the ba-tch brewing process, and the second class includiny the continuous processes.
In accordances with these processes, the wort ``
underyoes a given treatment while the crude grains such as rice, maize, barley and the like undergo another treatment which includes adding a fraction of mash oE wort or o~ enæyme.s from an external source. A given sacchariication diayram is used for each oE the brewiny raw materials, i.e. wort and crude yrains. To thiæ end, it i.s necessary to ~ncr~as~ the ~;~
temperature rom 45C to 7SC in order to ac-tivate the enzymes.
The tempera;ture is increased in stages, usually three stages.
The first staye occurs at a teinperature close to 45C
and during this staye the proteolysis of the treated product 20 - takes place. At the end of this staye, the temperature is increased close to 65C and during this second stage the action of beta-amylase occurs. The temperature is then increased to close to 75C to induce the action of alpha-amylase. The whole brewing process up to the saccharification of the mash which is carried out by increasing the temperature in stayes and by making use of an intermittently operating apparatus, lasts from 120 to 140 minutes.
The conventional brewincJ process i.9 appare~ntly yoverrled by severe operatiny restrictions in particular in respect of the time-temperature diagram, the milling and the nature o~
the separate treatment oE the crude yrains.

The continuous production of wort, however, yives rise ` ' ~

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to the following a~vantages:
- medium size of vessels, which then ope~ate at full load, the output being steady and buffer apparatuses which ~
are then sized in accordance with a permanent average ou-tput ..
instead of being sized in accordance with the.peak level of an equivalent intermittent output;
- ready and more efficient heat regeneration to the extent to which heat diffuses Ereely xather than being regenerated intermittently;
-possibility of providing, in a continuous process, successi.ve steps more suited to the requirements and demands .
of the natural proccsses along the paths Eol.lowed by the materials;
- :reduct:i.on .in op~:r~tincJ cost.s si.nce thc conventional ~equence o~ intermittent steps and operatic)ns is .replac~d by a succession o e steady opera-t.ing conditions during the `. :
process, this steadiness requiring fewer interventlons.
}lowever, the continuous process sufEers ~rom the . ~.:
following disadvantage~
- the treatment undergone by the mash is not uniform because parts or fractions of it pass through the apparatus .~ :
in times or along paths which are different and only the average conditions to which they are exposed can be controlled. ..
Accordingly, in order to attain the above mentioned ..
advantages, i-t is essential -to compromise between the . .
requirements of the natural processes and those of the ~ :.
.... .. .
continuous p.rocess. :.
I'his can be done by reducincJ the restrictions which `~ :
are improsed by the natural processes and by reducing the . .:~
i.rregularities within the treatment, the co-existance oE
which is inevitable, so that all of them meet the requirements imposed by the limits. To this end it has been found: .:
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- That the natural process requires overheating, for `;,., example that due to temperature gradlent in the laminar layer on the heating side walls, to be reduced in order not to affect .' the enzymatic potential before termina-tion of the transforma- '.: ' ~' tions which it. brings about. Through this measure which is :. .
obtaine~ by providing a strong and uniform agitationof the mash ', and by using a very hiyh ratio of heating surface to volume of wash in order to reduce the overheatiny to a few degress ;;, ' centriyrade, the brewing process may terminate at the end of ;.' theextraction and saccharification steps after about one hour. .
- That the brewing process produces a wort having average characteristics which meet the conditions referred to above for qulte dlferent "time-temperature" d.iacJrams. It `' .
would seem that the main variable is the total treatrnent time which controls the total ex.raction depend.incJ on ~he nature Oe the yrist, the type oE th~ wort,, th~ mash to water ratio, ., and the particles' si.~e. ....
- That a continuous gr.adual increase of temperature fro~ the mixing temperature to that o:E the order of 70 to ::
80C, at the end of saccharification gives a result comparable, ; , , .. . ..
as far as the eEficiency of the brewing process is concerned, with that of the brewing process carried out in discrete .` ':.
sta~es and this in~the order of an hour for the washing process. '.'~:
That when malt is first mlxed with all the crude , ,grains not previously processed at + 100C, saccharification '-is obtained! at the end of the gradual temperature increase, . . .
at about 77C and in just over an hour.
- That the extraction and ~ermentabili-ty losses pecu:l.iar to this practice and made manifest by black colouring by iodine of the'mash if the temperature is then increased ., to 100C can be lowered to an economlcally acceptable level ~,,.,, `', in view of the substantial simp~lifcation of the process and the . . ..

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apparatus and the possibilities of recovery from the spent malt, and of recycling, through a very fine milling of the crude grains which increases the part of thelr volume accessible, through the surface, to the enzymatic action due to the wort and through suitable choice of the temperature at the end of the brewing process.
It should also be noted that the requirement relating to overheatiny will be met in a more satisfactory manner with a continuous process where the extension of the apparatus in the material path direction is such that it assists the `;
surface to volume ratio. ;
As far as the other aspect of the compromise mentioned `;
above is concerned, i.e. the reduction oE the range o~
treatments co-existinc3 in a continuous brewing apparatus ;;
accorcling to the invention, the ollowing m~ans are employed:
- Verticcil c:Lrculation to pr~vent settlincJ from worseniny disparity of treatment and to obtain as far as possible a uniform distribution of the net speeds in a cross-section of the apparatus.
- Use of a reactor having several cells in series to reduce, by means of statistically defined compensations, ~the "dispersion of the dwelling times to average dwelling time" ratio to a value lower than that given by a single cell. r ' ' Configuration and operation of the stirrer chosen in such a way that this ratio is worsened to the least possible extent while meeting the requirements to prevent decantation and to assist heat and mass trans~er, which requirements justify stirrincJ.
; 30 - Conception of transition between adjacent cells inorder to recluce the "convection exchanc3e to net supply" `;' ratio in order to reduce the dispersion of the dwelliny times ?,'," ,, , ','"". ~

i ~ ~ 4 ~

-` 1036S22 and the co-existing treatments in the apparatus.
It has been found that the residual loss of extract due to the most unfavourable individual,treatments, i.e. those experienced by parts of fractions of the mash having the shortest transit or dwelling time throughout the brewing reactor, could be substantially reduced and attain only a few percent, even with minimum dwelling times considerably less " '' than an hour.
Thls remaining loss may b,e advantageously reduced even further by increasing the averaye dwelliny tirne and/or ,' by opposing the flow from one chamber to the other in the direction opposite to the net flow. However, the greater the '-', output for which the apparatus has been sized the greater , ,, the ratio of the size oE the cells with respect to that of ,, the transit oriEice therehetween. ~s a matter oE Eact, the size oE the particles recluires no!: too smAll a diam~t~r oE ; ``
the transmit orifice. The yr~ater the Elow the yreater the net speed throuyhout the throttled section and the greater , ,the turbulence which with a small diameter would tend to 20 ' establish undesired ex~hanges between the cells in the , direction opposite to the net flow.
Finally, it should be noted that the generalization of the recovery devices, particularly those operating on ' ' .
spent grains tends to displace towards an average extraction ' level the economic optima of the primary operations. In .
'~ particular, duriny~brewing, in view of the recycliny upstream the pressiny of the liquor obtained throuyh the spent grains, it may become pro~itable to reduc~ the investment at the expellses of the extraction level, which is almost'total, up to now, in the brewing operation.
The present invention in one aspect provides a brewing process for producing wort in which the mateirals are ~A~ ` 5 , I

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milled and mixed and at the end of the cycle a separation is carried out, wherein the materials pass through an apparatus ~;
in an uninterrupted flow and are subjec-ted to a single or .
distinct treatment distributed over several stagesof the apparatus, for both the grists ofthe malt and -the crude yrains, which treatment preserves the potential of each enzymatic ;`: ::
fraction by excludiny side wall overheating of the mash, the ~; ;
-treatment eomprisi.ng a proyressive increase of the temperature and a Eorced agitation whieh opposes settling and assists .;
renewal at the reaction-and exchange sites. .~
The i.nvention also provides apparatus for earryiog . ..
out the proeess aceording to the present invention eomprising a ~; :
eontinuously ope.rat.~ng reaetor having an ax.ial stirr~:r, the ~`
reactor comprls:ing vertieally arranc~ed eells eommunieat.ing in .;.
series ancl eeEeet.in~ the proeess :in stacJes, the eell~ h~ving ..
heating jaekets whieh eover most of their surfaees to reduee :
the temperature yradient in the mash due to heat exehange, these .:.
. . .
jaekets being eapable of being Eed separately or in series by .:
~ one or several hot fluid sourees to obtain differen-t temperatures 20 along the reaetor. `:
The invention wi.ll be further described, by way of example only, with reference to the aecompanying drawings, in .~-.
which~
: Figure l is a schematic diagram illustrating the process according to the invention; : .
Fiyure 2 is a schematic view of apparatus Eor earrying out the proeess aeeordincJ to the invent.ion, .i.n which ~;
erude .grains undercJo a prel.iminary treatment beEo.re .reaehiny . the malt mash to underyo a :Eitial common treatment, the apparatus ..
eomprisiny two similar reae-tors;
Fiyure 3 is a diagrammatie vertieal eross-seetional .
view of a eontinuous brewing reaetor; and ...,~, .....

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1~36S2Z
Figures 4 to 6 are enlarged views showing several .
forms of reactor cells of the type illustrated in Fi~ure 7. '.~
In the process illustrated in Figure l in a first .' s-tep A mixing water l, malt in the form of.standard ground ... ...
mixture 2 and crude grains in the form of a fine ground mixture 3 are cont1nuously mixed. After mixing, the act1ons of beta- .' .,.
glucanases and'proteases commence at about 40C. The m.ixtur'e .' is continuously transferred'from A throuyh A pumping assembly ~ ''.
B to a mashing reactor C in which the.treatment is progressively increased to about 77C. 'The resulting mash is fed to a ',,:' , continuously operatiny separation assembly in three steps. The ",', first step Dl provides the first sweet wort 5, the second step ' ':.
D2 provides the Eirst sparging 6 and the th.ir,d step D3 which after separation ~rom the sparginy water~ provicles th~ seconcl sparyiny 7 recyclecl to the step D2. ~Eter this third separatlon step D3, a li.quor lO is extract~d through a poss.ible treatm~nt F of the spent grain 8, which may assist mixing at ~. The . , sweet wort 5 and the sparging 6 allow wort'9 to be obtained which .' underyoes A continuous treatment at E. . ' ', ~20 In the convent'ional processes, the malt.and the crude '~,' '' yrains are treated separately., The treatment for malt comprises , .' '' 1, , .
operati.ons such as mill,ing, water yrist mixture and brewing -.
proper.~ In the apparatus shown in Figure 2, the malt stored in a silo~71 is first~we1qhed~by means of a platform scale 72 and :is then forwarded to a mill 74. The mill 74 allows a particle size of:the malt to be obtained such that it is possible to :'~
adjust the skin size and to'obtain a very high flour output. :.
The ground mixture oE malt is ~ed to tank 76 khrough a condu.it .,.
75~, and water is supplied to the tank 76 vLa a conduit 77.
'30 The malt gri.st and water are mixed in the tank 76. This mixing is carried out at a temperature which assists the activity of '.
beta-ylucanases and proteases. The water grist mixture, i.e. the ~:

_ 7 _ .3 io365~Z ,~
mash, is pumped by a pump~12 through a conduit l.1. The pump 12 '.
feeds -the mash through a conduit 13 to a continuously operati1l~ ~.',,' brewing reactor 15 which will be described below and which is '-''. ,.:
illustrated in Figure 3. ~. . :
At the same time, the crude grains undergo,a separa-te ,'~
treatment. The crude grains which may comprise maize, rice, '', .
barley and the like reach,the part of the apparatus indicate'd ,~ ''': .
by re:Eerence numeral 78, and then are weighed by a plat~orm ,,, ~,' scale 79 and ~all lnto a mixiny tank 80. ~ixing wa-ter is ' .,;, supplied to the tank 80 through a conduit 81, and a fraction '-.. `': ' of the malt mash 83 from the reactor 15 is also supplied to ,~
the tank 80 through the conduit 82 throuc3h either the pipe 69',.~ ...
or :the pipe 70. The resulti.ng mixture comprisiny the ground . :' mixture.oE -the crude grains, mixiny water and a Eraction oE ' malt mash is pumped by a pump 85 Erom the tank 80 throucJh conduit 84 and supplied through a conduit 86 to a sccond continuously operating brewiny reactor 15l which is substantially .,' the same'as the reactor 15. In particular the second reactor ,;''',;
15 has a stirrer 51`opera.ted by a motor 5~. ' , .
The mash of crude grains.leaves the reactor 15l ,,~
through a conduit 87, fl.ows through a heat exchanger 88, and '.'.. .:.
,, .
flows throuyh a conduit 89 back to the mixiny tank 76. . ....... '~.
A by-pass 90 is provlded in the conduit 89. Thus the mash of .. ,: .

crude grains from the heat exchanger 88 can,also be injected ' ''.
into the~malt reactor 15 at different temperatures ranging ",.
from 35C to 80C in accordance with the enzymati.c state of the malt and the desired composition oE the wort, the i'nlets to the , '~
reactor 15 being through the pipes 69 or 70. `. ', The mixture of malt mash and crude grains Erom the , ':
mixing tank 76 1s pumped into the reactor 15 and discharged .,: ,, through a.conduit 16 to be Eed to filtration apparatus 18 in ', .which the continuous separation operation takes. place and wort l9 ~,', ;~ .
is obtained.

~ 8 - ',', " .
. ...

, According to the known processes, the mash of crude -'. .
. .
grains is mi,xed with a low proportion of malt mash of the ordcr of 5 to 25~, which allows a certain enzyma-tic activity to occur which is absent in the crude grains. Moreover, this mash of ~ . ...
crude grains undergoes a temperature increase by stages. The ,:~:
first stage ranges from 75~ to 85 and is called liquifaction .''. :
or gelatinization, and the second s-tage occurs at 100C and .~.
partly hydrolyses the starch-water mixture. ,~ `
~owev~r, the temperature increase may be.progressively 10 , increased by means of the reactor 151. The mash of hydrolysed .
crude grains.may'be cooled to a temperature of from 35C to ' .... ' 50C and remixed with the ground mixture of malt to which water .' has been added. ~t temperatures of from 35C to 50C the ' .
,activity of the beta-glucanases and certain proteas~s ta]ces ~:.
place.
It shou.ld be noted that .Eor both th~ t.r~atment oE th~ '' malt mash and the separate.treatment of the mash of the crude~::
grains, lt is possible,to provide a different progre.ssive ~. ' temperature increase of the temperature stage system applied ';
in conventional brewing~methods. Thus, in the case of the malt'', mash the progressive temperature increase in the reactor'15 is`' from about 30C;to about 80C, and in the case of the mash of .
crude~grains the~progressive temperature increase in the ~: . second reactor 15 is from about 30 to about 100C. These increases may be in the form of a straight line or of a number,.
of.curves which are calculated from data of the degrada-tion oE~.
~: ' the protein materials and the carbohydrates compounds.
The continuously opera-tinc~ brewing reactor 15 shown;.
in Figure 3 is vertically arranged and may compri,se several sections. The first section forms the bottom 21 of the reactor and includes an inlet pipe 14 for -the mash. The upper part of the first section 21 comprises a flange 22 which is applied ':~

'' 1~36~
:. against a lower flange 23 on the second section 24. A toroidal ' : ,:' . .
seal 25 ensures ti~htness between the flanges 22 and 23, the ., latter be.ing held by fixing elements 26. The upper part of . :~
the second section 24 comprises a second flange 27 on which a ~ .
guide flange 28 is placed and serves as connecting element ' .,, ,:.
~. .: ..
between the flange 27 of the second section and a lower flange . . .
29 of.the third section 30. Toroidal seals 31 and 32 ensure ,' .,~
tiyhtness between the 1anyes 27 and 28, and between the ' ' flanges 2~ and 29. ~ixing elements 33 connect the second and '.
the third sections 24 and 30.
. The upper part of the third section 30 comprises a second flange 34 provided with a toroidal seal 35 on which a . ,.
second gulde flange 36 is placed. Between the guide flange 36 ,.
an~ a lower flange 37 of a fourth secti.on 38 is p.rovided a ;
seal 39, and fixing elements 40 connect the thirdi s~ction 30 and the fourth section 38. '.rhe upper,part o~ the fourth , `' ' section 38 comprises a :Elange 41 which i5 connected through fixing elements 42 to a flange 43 integral with a fifth :' section 44, a toroidal seal 45 ensuring tightness be-tween the ' .
flanges 41 .and 43.
A fifth section 44 which forms the lid of the reactor lS includes an outlet conduit 16. The lid includes turning '',. '~
seals 46 through whlch seals and the guide flanges 28 and 36 :
~: ~ having guiding bearings 47 passes a shaft 50 of a stirrer 51 ~, :
i ~ .
~ ~ ~ having blades.52. The shaft 50 is coupled to a driv.ing motor .
: ' 54 by means of a coupling 53. , ~ :
The sections 2~, 30, 38 comprise a series of brewing ~.. "
cells 55 to ensure, from the hydrodynamic poin-t o.E view, , favorable decomposition conditions in severAl stages of the 30process. ...

The,reactor is heated by a plurality oE thermostatic heating pockets 56, 57 connected to each okher by sections as ' ' -illustrated in Figure 3; the pockets 56, 57 may be for example ,.:"
of triangu'lar s.ection to allow the heatin~ surface to be . '-.
increased. A heatlng syste~ is obtained the heat gradient of which between the heating side wall 58, 59 and the mash lS very :''' small. This allows the enzymatic potential of the mash to be :- .
preserved, i.e. the quality and quantity of the enzymes can be '' preserved. This temperature variation between the heating fluid and the substrate cloes not exceed a few deyrees centigrade.
. The pockets 56, 57 have pipes 60. .Thus, for the second section 24, the heatiny fluid can enter through pipe 60, flow throuyh the pockets of successive cells by means of ' ~.
connections 61 between the pockets 56, and discharge through a pipe 62 leading to the supply tank (not shown) supplying heatiny fluid. Similarly, Eor the th.ircl section 30, the heating fluid can enter through a pipe 63, flow through con,nections 6~
and discharge through a pipe 65. ,l1he in~et o~ the ~ourth . ..
section 38 is formed by a pipe 66 and its outlet by a pipe 67, connections 68 ensuring the transfer of the heatiny fluid.from one pocket to another. Pipes,69, 70 are provicled at different locations.in the reactcjr 15 and allow mash to be removed or supplied,:for example in accordance with the recluirements of :
~ a mash............................................................... -, : Heating may be provided for each section 24, 30, 38 '~
: thereby ensuring a progressively increasing temperature of ,~
the mash. Thus, section 24 is at a temperature between 35 ancl ~-::: ',.
50C its upper part:being a-t 50C and its lower part being at .~.
35C. The section 30 has a temperature between 50C and 65C, its upper part being at 65C and its lower pa.rt being at S0,C.
Sec.tion 38 has a temperature between 65C and 80C, its upper part being at 80C ancl its lower part being at 65C. This , results in the mash undergoing a proyressive temperature increase from about 30C to about 80C in a -time interv~l of .;-..

an hour. `
The above described process and apparatus havc the following advantage: ;
In the apparatus which comprises series communicating cells through which a mechanically stirred fluid continuously flows, transfer from one cell to the next is often the result -,:
of convection movements in the two directions (see Figure 7).
This phenomenon is sometimes calIed "back-mixing" and is ~;
particularly effective when agitation is intense and when flow between cells is not unduly restricted.
This phenomenon has, however some disadvantages~
-Levelling of various elements of the transformation potential.ity of the treated materials (for instance, tendency of the liquid extract rate to become uniform alonq the reactpr) -Loss o~ a part oE the advan~age theorectically attainable by employincJ series-connected cells: the contractlon in the distribution of the dwelling times (at the various thermal and biochemical stages) is a minimum only in the ideal case, and this results in a lower homogeneity in the succession of transformatlon conditions experienced by the mash and thus in a part of the latter undergoing treatments quite different ~. .
~ from the optimum treatment which can be imposed only as an - ;,., ~ -: .
! - ' "
-Owing to uncontrolled forward and backward movements superimposed on the net output, enzymatic fractions undergo ; harmful overheating bèfore they -terminate the intended bio-chemical transformations.
Xt has been suggested that brewi.ng in three temper-:, , ature stages does not correspond to an acute need, indeed the complex enzymatic transformations distributed along the sequence o the temperatures undergone during brewing leads to sub-stantially equivalent results for a large variety of heat .'.'~

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-~" 103~;SZZ
diagrams possible in a given time interval.
This leads to successful continuous production despite the disadvantages mentioned above, b~t it is apparent ~:
that the efficlency suffers from an excessive dispersion of the treatments imposed on the various elementary volumes of mash, particularly i~ the successive exchanges therebetween ean only partially attenuate the consequences of this ::.
dispersion. . ': .
rrhis dispersion ean be maintained within aeceptable limits,by redueing the baekmixing throuyh one or more of the following means:
-Restraining the passage from eaeh eell to the nbxt (the eonstruetion ean be modi~ied to allow the sti,rrer to be suitably mountecl).
-Reduction o.f stirrincJ intensity to a min:imum.
-~nstalling a means b~tw~en the cells to a~sist flow in. the direetion imposed on the reaetor, even exelucling the' passage in the opposite direetion.
, The ~assac3e 91 from each ee].l 551 to the next eell 552 is restrained and agitation is reduced to a minimum. It is also possible to install between the eells 551~ 552 a-t~the passa~ge 91 a means which assists the flow in the direetion .::
: imposed on the reaetor 15 even by exeluding the passage in the ,:
op.posite clirection. "' .
~ ~As shown in F,igure 4, this means may comprise a screw : . or a helix 92 mounted.on the shaft 50 of the stirrer 51. This .
..
serew or helix 92 creates a pumping.ef:feet whieh may be adjusted aeeordiny to the output o~ the reactor 15.
~s shown in ~igure 5, the means may alte.rnatively 30 comprise a non-return valve 93 arranged between,the.eells 551~ '' 552. 'rhe valve 93 may comprise a 1exible dise or membrane 94, :~
for example of rubbe.r, having a eentral opening 95 for reeeiving ', .
-.13 - ,., FA :

. .
the shaft 50 of the stirrer 51. The flexible disc or membrane 94 rests on the periphery of an electro-magnet 91 and is hel~ ~ ~in position by a ring 96 integral with the shaft 50. When the ` ~ -mash is forced in the direction of the arrow A, the disc or - -membrane 94 is flexed thereby allowing the mash to flow only - -in one direction. When the mash flows in the opposite direction -lt pushes the disc or membrane 94 against the periphery of the passage 91 thereby cutting off -the flow.
Since brewing involves exchanges between liyuid and particles suspended therein, it is necessary to prevent settling which would tend to have a harmful effect on the conditions under which this exchange takes place and could also overfill ;
the reactor. i ~, In addition to assisting heat transEer and also mass trans~er between particles and liquid, the ayitation tends to prevent settling.
This, however, inv~lves the following disadvantages:
-reduction in the particle size prevents further separation;
-backmixing is increased by increasing agitation.
- These disadvantages may be overcome by the following means: ~ , Confinlng the size dlstribution of the particles by providing dry milling in several passages and screening and recycling between the passages. In this manner, by bringing the size of the fines which generate the filtration close to -that of the coarse particles, which impose a detrimental strong agitation in other respects, the disadvan-tag~s reE~rred to above are reducecl.
-Adoption of a configuration which prevents filling up with minimum agitation: cells 551~ 552 may for example be shaped in the form of a pear so that the centrifugal movements .;. ~ .
~Al `"':~

- ~0365Z2 yenerated by the stirrer 51 are deflected upwards. In addition, blades 52 may be provided in each cell 551~ 552 in the zone 97 where a stagnant deposit of particles would tend to occur (see Figure 6).
The movement of the liquid within the reactor consists of a imposed flow and turbulent movement. The particle.s follow the movement of the liquid and move close to each other to a given extent, although this movement is less the heavier the particles and the shorter the duration oE the turbulence.
The movement of the particles also comprises a slow - component downwards settliny, and the consequences of this may be reduced by the agitation and through a suitable choice of the grain size and the cross-section of the reactor. This gives the particles a dwellincJ tirne in the reactor longer than that of the liquid and this .is more so the heavier the particles and the loncJer the treatment t.ime they recluire.
~ t i.s preferred to proceed as Eollows as far as the duration and completion of the brewing extraction are concerned:
-Circulating the mash of the reac-tor upwards from below.
-Obtaining a balance between the~parameters which assi~st settling and those which oppose it so that there occurs a residual settling without causing total stagnation of the heavlest particles.
-The efficiency of the brewing operation and that of the separation downstream thereof is found to be sensitive to the initial solid/liquid ratio. However, the finished wort is subject to a minimum density constralnt. The optimum distri-bution of the total water between that fed to the inlet and that used to wash the spent malt may differ from that required in a batch process; it may also diEEer in a continuous process depending upon whether the cirFuIation is upwards or downwards ~` ~036S;~Z
`' in the reactor, particularly when the circulation is downwards '' while employing a finer milling, a more dilute mash and less washing water than in a conventional brewin~-for a wort of given density.
It is advantageous to recycle the last sponging .
liquor either at the stage preceding the separation or during ~ , brewing. When this recycling is carried out during brewing, it '~
may take place -towards the end of the proteolysis operation, ', " ' giving rise to the following advantages: ,' -Dilution of the mash favorable to amylolysis when ,, the,same is likely to be harmful to the proteolysis which would better occur in a thick mash. ' j~
-F,ffect of shifting the pll in a direction favorable ,'',~, to amylolysis th~ requirements of which differ ~rom those of the proteolysis. ~;" " , -Contribution t'o the temper~tur~ increa~e oE the mash "' , in the reactor. . ..
-Minimum disturbance of the ex,traction poten-tial by feeding'the sponging liquor when the mash has attained a ~; ' ,;
density of the same or~,er as that of these liquors. `' It has been found that part of the tr~ansformations . .
due to proteases and beta-glucanases could be advantageously carried out in the mixer upstream of -the reactor at an average ,, ~
temperature of from 35 to 45C in this apparatus. ,~ ;
~,- :

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Claims (19)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A brewing process for producing wort in which the materials are milled and mixed to form a mash and at the end of a cycle a separation of the wort is carried out, wherein the mash passes through an apparatus in an uninterrupted flow and is subjected to a single treatment distributed over several stages of the apparatus for both the grists of the malt and the crude grains, which treatment preserves the potential of each enzymatic fraction by excluding side wall overheating of the mash, the treatment comprising a progressive increase of the temperature and a forced agitation which opposes settling and assists renewal at the reaction and exchange sites.

2. A process as claimed in claim 1 comprising vertical discharging during brewing, and reducing, the variety of treatments experienced by the materials because of the continuous operation and the tendency of the mash to undergo settling by subdividing the brewing operation into several stages.

3. A process as claimed in claim 1 or 2 comprising reducing the extent of convection exchange upstream and down-stream to a minimum, as these exchanges are superimposing the net output between successive stages and increasing the differences in treatment within the brewing apparatus.

4. A process as claimed in claim 1 or 2 wherein discharging imposed in the apparatus occurs in the upward direction and advantage is taken of the tendency of the particles to settle to ensure a longer dwelling time for the particles than for the liquid by establishing a balance between the settling actions and the reactions opposed thereto so that an average upward speed of the particles is obtained due to the imposed output, the turbulence and gravity, which speed is less than that of the fluid.

5. A process as claimed in claim 1, wherein in the separation at least one of the last spongings at the end of the filtration and the liquor which may be pressed out of the spent grains is recycled upstream.

6. A process as claimed in claim 5 wherein the recycling takes place during brewing where the mash has already undergone a partial extraction and a substantial proteolysis.

7. A process as claimed in claim 6 wherein an adjustment of the pH of the water is carried out upstream of the mixer and advantage is taken of the effect on the pH of the mash of the recycled sponging waters to improve the pH of the proteolysis and amylolysis phases.

8. A process as claimed in claim 1 or 2 wherein brewing is carried out at temperatures of from about 30° to about 77°C during mixing the malt milling product and the crude-grain milling product, the latter being previously untreated at a high temperature with mixing water.

9. A process as claimed in claim 1 or 2 wherein the brewing is continuously carried out at temperature ranges corresponding to a conventional diagram in two parts for using crude grains in addition to the malt, this diagram being followed without definite temperature stages in two similar reactors, the first of which receives the mixture of malt and the pretreatment product of the crude grains produced in the second reactor.

10. A process as claimed in claim 1 or 2 wherein the milling has a narrow particular size distribution, obtained from a dry milling in several stages, with recycling between the stages, so that the finest particles do not retard filtra-tion and the coarser particles undergo a sufficient treatment even during the shortest dwelling time through the mashing apparatus.

11. A process as claimed in claim 1, 2 or 3 wherein the enzyme action first occurring during brewing, takes place substantially in a device for mixing the milling product or products with brewing water at a temperature of the order of 40°C.

12. A process as claimed in claim 1, 2 or 3 wherein the total amount of water used for producing a wort of a given sponging of the spent grain, according to an optimum proportion as far as the efficiency of the total extract is concerned.

13. A process as claimed in claim 1, 2 or 3 wherein water is circulated downwards in the apparatus, and finer milling, more dilute mash and a smaller amount of washing water are used than in conventional brewing for a wort of given density.

14. Apparatus for producing wort in a brewing pro-cess, comprising a continuously operating reactor having an axial stirrer , the reactor comprising vertically arranged cells communicating in series and adapted to effect the process in stages, the cells having heating jackets which cover most of their surfaces to reduce the temperature gradient in the mash due to heat exchange, these jackets being adapted to be fed separately or in series by one or several hot fluid sources to obtain different temperatures along the reactor.

15. Apparatus as claimed in claim 14 wherein the reactor comprises successive sections comprising several cells or parts of cells mounted together by means of flanges and having guide means for guiding a vertical shaft carrying stirring blades, an inlet and an outlet at the ends of the reactor and means therebetween for supplying raw materials and for drawing samples for control purposes.

16. Apparatus as claimed in claim 14 or 15 wherein the reactor has a substantial pressure drop between successive cells due to throttling in the passages between successive cells and due to opposing turbulent movements which are super-imposed on the net flow through the cells.

17. Apparatus as claimed in any of claim 14 or 15 wherein the flow in the direction opposite the imposed flow is prevented either by providing a screw or helix on the shaft of the stirrer in the space between the cells, this screw or helix creating a pumping effect, or by providing a non-return valve between adjacent cells.

18. Apparatus as claimed in claims 14 or 15 comprising a single reactor for the common treatment of malt and crude grains.

19. Apparatus as claimed in claim 14 or 15 comprising two reactors the first of which receives the mixed malt and the pretreatment product of the crude grains produced in the second reactor in which a first treatment of the malt and the treatment of the complete mixture occurs.