CA2096017A1

CA2096017A1 - Lauter method under pressure

Info

Publication number: CA2096017A1
Application number: CA002096017A
Authority: CA
Inventors: Kurt Stippler
Original assignee: Individual
Current assignee: Anton Steinecker Entwicklungs GmbH and Co
Priority date: 1990-11-13
Filing date: 1991-11-12
Publication date: 1992-05-14
Also published as: EP0557326B1; EP0557326A1; DE59105014D1; DE4036078A1; JPH06504193A; ATE120232T1; WO1992008782A1; DE4036078C2

Abstract

ABSTRACT

The present invention refers to a method of lautering mash in a lauter tub for brewing. In order to improve known methods of this type, the present invention provides the feature that the lauter process is, at least partially, carried out under excess pressure generated by feeding inert gas into the lauter tub.
In addition, the present invention suggests an ap-paratus by means of which the method according to the invention can be carried out.

Description

209~17 A L~uter Netho~ er Pressu Desoriptio~

The present invention refers to a method of lautering mash in a lauter tub for brewing.

The lauter process is one of the most important method steps in brewing. As is generally known, the wort is obtained in the lauter process by separating the solid components of the mash from the liquid ones. The solid components remain on the bottom of the lauter tub, whereas the wort can then be removed from the bottom of the tub. The wort which is flow-ing of~ first is called first wort or original wort. When this wort has been removed, a considerable amount of extract -is still contained in the spent grains. In order to obtain this residual amount, the spent grains are subjected to ex- -traction by a treatment with hot water. This process is called sparging. The water which flows off last from the spent grains contains only a small amount of extract (Glatt-wasser).

The spent grain ma~s compacts more and more in the course of lauter process. Hence, a chopping device, which rotatingly circulates in the lauter tub, is normally used ~or chopping or lossening the spent grain mass at least at certain inter-vals.
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; For some time, it has now been endeavoured to carry out, as far as possible, the lauter process such that the loosened spent grain mass comes into contact with the least possible amount oi oxygen, since it turned out that the quality and especially also the keeping quality of beers is negatively in~luenced when an excessive amount of oxygen is introduced : ' ' ,, . '-, ,, ' .'' ., : , , '. ." : ~ ~ ' ~ . :, 209~1P~
during the lauter process (cf. the inventor's publication in "MBAA Technical Quarterly" vol. 23, pages 54 to 61, 1988).
This problem is also discussed in German-Offenlegungsschrift 39 42 980. Said German Offenlegungsschrift especially men-tions that the atmospheric oxygen normally introduced in the spent grain mass during the sparging process is disadvanta-geous, and, in order to reduce this proble~, it is suggested that the sparge water should be introduced in the spent grain mass via the support arms of the chopping device. The aim to be achieved by this measure is that the sparge water is sprayed close above the spent grain mass whereby the quantity of the atmospheric oxygen entrained by the sparge water will be reduced on the whole.

It is the object of the present invention to suggest a lauter method which has been improved still further in com-parison with the prior art.

In the case of the method according to the present inven- :
tions, this is achieved by carrying out the lauter process, at least partially, under excess pressure generated by feed-ing inert gas.

This execution of the method offers important advantages in comparison with all hitherto known lauter ~ethods. On the one hand, squeezing of the spent grain mass will be achieved by the generation of the excess pressure, ~hich takes place at least during certain phases of the lauter process, and this will have the effect that the first wort yield, the so-called first wort extract, can be increased substantially.

Especially when poor malt qualities are used, in the case of which the spent grain resistance is comparatively high, an improvement can be achieved by generating the excess pres-sure. In addition, shorter lauter times will thus be ob-.

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2as~ 7 tained because the passage o~ the liquid through the spent ~rain mass is 'lartificially" accelerated. In the final anal-ysis, the better first wort yield will then also result in a Glattwasser containing even less extract in the way desired.

5queezing of the spent grain mass is, in pxinciple, already known. If, however, the squeezing were performed under ex-cess pressure with the air which i5 normally contained in the lauter tub, the introduction oP air in the spent grain mass, which is, in principle, not desired, would even be in-tensified. Hence, lautering under excess pressure in the lauter tub has not been carried out so far. However, in view of the fact that the present invention uses inert gas for generating the excess pressure, the advantaqes aimed at can be achieved without any disadvantageous influence on the quality of the beer. On the contrary, the quality and espe-cially the keeping quality of the beer is improved still further because the atmosphere in which the lauter process takes place is an inert gas atmosphere so that the spent grain mass will absorb only an insignificant amount of oxy- -gen or no oxygen at allO

In detail, a large number of variations is obtained ~or the method according to the present invention.

It may, for example, be advantageous to choose the excess pressure in response to the spent grain resistance. In view of the fact that, as is generally known, the spent grain re-sistance increases in the course of the lauter process and can be reduced by means of the chopping device at certain intervals, it may be avantageous to adapt the excess pres~
sure to the spent grain resistance values; in this connec-tion, a small pressure differencP should be aimed at in each lndividual case. An automatic closed-loop control can be provided in this respect as well. For this purpose, it would ., , . .. . :~
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only be necessary to measure, in the manner known, the spent grain resistance, and to input the result in a controller, which will influence the excess pressure in a suitable man-ner by feeding the inert gas into the lauter tub or by per-mitting it to escape from said lauter tub.

The spent grain resistance can be detected in various ways.
On the one hand, it is possible to carry out pressure dif-ference measurements, in the case of which the pressure is measured above the spent grain mass on the one hand and at the bottom of the lauter tub, i.e. below the spent grain mass, on the other, whereupon the values are compared with each other. The higher the pressure differ~nce, the higher the spent grain resistance. It is, however, also possible to datect the spent grain resistance indirectly by measuring the flow rate in a discharge line, a method which has al-ready been ~escribed in detail in German-pat. 38 44 389. The pressure difference measurement as well as the flow rate measurement provide the desired information on the spent grain resistance, and, on the basis o~ this information, the excess pressure can ~hen be adjusted accordingly. The flow rate measurement proved to be particularly advantageous in this connection.

It is, of course, not necessary that the inert gas atmos-phere in the lauter tub contains exclusively inert gas. A
percentage of at least 20 % of inert gas will already pro-vide a considerable improvement with respect to the aimed-at result.

The inert gas used can e.g. be nitrogen or also Co2 or a mixture of these gases. It is also imaginable to feed heli um, although helium is comparatively expensive. Since it is, however, possible to circulate the helium in a circuit~ los-ses can be kept low.

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Moreover, an advantageous effect can already be achieved by purposeful feedin~ of the inert gas, e.g. in the area close above the maximum filling level of the lauter tub. The inert gas, which will then sweep over the surface of the mixture of water and mash, will form an intermediate layer between the residual air above said intermediate layer and the liq-uid so that a direct introduction o~ oxygen will be pre-vented in this case as well. In this connection, it would also be imaginable to feed the inert gas during the sparging process in such a way that it will wash around the spray nozzles by means o~ which the sparging water is introduced so that in this case, too, the amount of residual air which will be entrained in the lauter tub can be reduced.

The pressure value need not be maintained constant through-out the whole lauter process. It can also be increased or reduced in the course of the process. Pressure values be~
tween 10 and 100 mb, in particular those between 20 and 50 mb, proved to be suitable pressure values.

~n apparatus for carrying out the method according to the present invention is characterized by the features that the lauter tub is constructed such that it is pressure-tight and is provided with at least one inlet for feeding an inert -gas. These measures are the precondition under which suit-able excess pressure values can be generated in the lauter tub.

In accordance with an additional advantageous embodiment, the lauter tub has associated therewith a pressure gas stor-age for storing and recirculating the inert gas. The pres-ure gas storage can feed the gas into the lauter tub, when the inlet at thQ lauter tub is opened~ and, when aeration o~ the lauter tub is required, the presæure gas storage can previously remove the inert gas via a pump and re-store it , . . . , ., .. .: . , . , ., .,, . . . ~, . . ., . . ,, :,.. , . . , , - , . :... .,, : , .
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until the lauter tub will be pressurized again.

The method is applied in an advantageous manner in connec-tion with a lauter tub provided with a rotatably driven chopping device. In the case of the method according to the present invention and in the case of the apparatus according to the present invention, it is possible to operate the chopping device again and again or even continuously, with-out any risk of introducing, by excessive loo~ening of the spent grain mass, an excessive amount of oxygen into said spent grain mass because an inert gas atmosphere is produced in the lauter tub. For making the lauter tub pressure-tight, a closure flap can, most simply, be arranged in the dis-charge means of the lauter tub, the opening positions of said closure flap being adjustable in a variable manner. The desired closed-loop control or also the desired control of the pressure can thus be carried out in a very simple man-ner.

In the following, the present invention will be explained and described still further on the basis of the embodiment shown in the drawing.

The only ~igure shows a flow chart of an apparatus according to the present invention on the basis of which also the exe-cution of the process will be explained hereinbelow.

In the drawing, reference numeral 1 has been used to gen-erally designate a lauter tub, which is equipped with a ro-tatably driveable chopping device 2 in a manner known per se. The chopping device carries chopping blades 3, which are effective in the area of spent grain mass 5 depositing on the bottom 4 of the lauter tub during the lauter process.
How this can be done in detail is disclosed e.g. in German- :

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209~1'7 pat. 38 44 389 so that a comprehensive explanation of these processes can be dispensed with in the present connection.

The lauter tub is provided with various feed lines and dis-charge lines in a manner known per se. The feed line 6, through which the trub to be lautered can be fed, is sche-matically shown. Reference numeral 7 has been used to des-ignate the line for feeding the sparge water. The wort can be removed from the bottom 4 of the lauter tub 1 via the line 8, which is schematically outlined at this location.
In accordance with the present invention, the lauter tub is constructed such that it is able to resist an excess pres-sure of up to approx. 1 bar above atmospheric pressure. At the discharge means 9 of the lauter tub, an adjustable valva flap 10 is provided, which is fully closed or adapted to be adjusted to various opening positions. The positions of this valve flap can be adjusted via a central control and regu-lating unit 11. In addition, the lauter tub 1 can have con-nected thereto a pump 12, which is connected to a pressure gas storage 13 for inert gas. This pressure gas storage opens into the trub feed line 6. ~hen the pressure feed line 6 is closed at its free end (not shown), pressure can be introduced into the interior of the lauter tub 1 via said line.

The lauter tub has additionally arranged thereon two pres-sure sensors 14 and 15, which permit a determination of the spent grain resistance. The result of this measurement is also proce~sed in the control and regulating unit 11.

An alternative possibility of detecting the spent grain resistance is also indicated in the drawin~. In the case of this alternative possibility, a flowmeter 21 is arranged in a discharge line 20, said flowmeter permitting a detection o~ the variations of the rate of flow per unit time in re-, , . ., . ,,, ., ~ ,. , ., . , ., . . , ,, . ~ ~ .

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2 ~ 7 sponse to time. This result can then also be inputted into the control and regulating unit 11, where it can then be used for internal pressure control.

Instead of the valve flap 10 shown in the drawing, a con-stant closure of the flap 10 is imaginable as well; in this case, pressure control can be effected via the relief valve 22, which is shown as an alternative possibility.

In the following, one of the possibilities of executing the lauter process according to the present invention will be described.

For the purpose of lautering, the mash is first pumped via the line 16 from the mash tub, which is not shown, into the -lauter tub 1. When this process has been finished, the spent grain mass will deposit on the bottom 4 of the lautsr tub, whereas the first wort will accumulate above the spent grain mass. The lauter tub can now be closed in a pressure-tight manner via the flap 10. When the lauter tub has been closed in a pressure-tight manner (in the course of this process also the valves in the other feed lines and discharge lines are closed), the air contained in the lauter t~b can first be sucked off via the pump 12, i.e. at least a partial vac-uum can be produced. By opening valves, which are not shown in detail, it will then be possible to feed the inert gas compressed in the pre~sure gas storage 13 Prom said storage i~to the lauter tub so that a pressure of up to 1 bar excess pressure will be generated in said lauter tub. This excess pressure has the effect that the first or original wort ac-cu~ulating above the spent grain mass can be obtained more rapidly and that, at the end, part oP the residual first wort is squeezed out of the spent grains. A higher yield of first wort will thus be achieved. After the removal of the first wort via line 8, air is prevented from being intro-" . ' ' ' , . , , ' ' ' , : '. ~ ', ' - . . . -. . , : :

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duced in the spent grain mass together with the sparge water fed via line 7, since an excess pressure, generated by an inert gas atmosphere, has already developed in the interior of the lauter tub. It follows that the introduction of an excessive amount of air into the wort and into the spent grain mass, respectively, is prevented throughout the whole lauter process.

During the lauter process, the spent grain resistance can be measured continuously. Depending on this spent grain re-sistance, the chopping device can, in a manner known per se, be raised or lowered, or it can be caused to perform a rota-tional movement. Moreover, said spent grain resistance can also be used for controlling via suitable signal lines 17 and 18, respectively, the pressure in the lauter tub such that said spent grain resistance will be minimized.

The pressure gas storage can have provided therein inert gas in the form of N2 or C02 or also helium. A mixture of this gases is imaginable as well. In view of the fact that, after termination of the lauter process, when aeration of the lauter tub is required, the pump 12 permits the inert gas to be removed from the lauter tub and to be then restored in the pressure gas storage 13 with the aid of a compressor -means which is not shown either, the inert gas can be used in a circuit so that no inert gas will be "wasted".

The generation of an excess pressure by means of the inert gas can take place throughout the whole lauter process; it can, however, ~ust as well su~ice to work with an excess pressure only during specific phases, e.g. during the phase in which sparge water is supplied, during the phase in which the first wort is obtained, or also between these phases.

A plurality of advantages are achieved by generating the ex-', ', , ' . . ~
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2~9~1 7 cess pressure in the lauter tub, these ad~antages being e.g.
an increase in the amount of the first wort extract, no oxi-dation of the wort nox the resultant deterioration in quali-ty, less Glattwasser, clearer wort and, finally, also the possibility of using finer bruised grain. ~oreover, more brewing operations are carried out per unit time, since the time required for the lauter process can be reduced. Final-ly, the method is also advantageous in the case of poor malt qualities with high spent grain resistances, since the squeezing of the spent grains under excess pressure permits even in these cases acceptable first wort yields.

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Claims

Lauter method under Pressure Patent Claims

1. A method of lautering mash in a lauter tub for brewing, characterized in that the lauter process is, at least par-tially, carried out under excess pressure generated by feed-ing inert gas into the lauter tub.

2. A method according to claim 1, characterized in that the excess pressure is chosen depend-ing on the spent grain resistance.

3. A method according to claim 1 or 2, characterized in that the excess pressure is controlled automatically in response to the spent grain resistance and/or the rate of flow.

4. A method according to at least one of the preceding claims, characterized in that the excess pressure is chosen such that it is up to 1 bar above atmospheric pressure, but preferably such that it is 10 - 100 mb or 20 - 50 mb above atmospheric pressure.

5. A method according to at least one of the preceding claims, characterized in that the excess pressure generated by means of inert gas is generated at least during the phase in which the first wort is obtained by lautering.

6. A method according to at least one of the preceding claims, characterized in that the inert gas used for gen-erating the pressure is N2 or CO2 or a mixture of these gases.

7. A method according to at least one of the preceding claims, characterized in that, after having been used for pressure generation, the inert gas is temporarily stored in a pressure gas storage and is then re-used for pressurizing the lauter tub again.

8. An apparatus for carrying out the method according to claim 1, characterized in that the lauter tub (1) is con-structed such that it is pressure-tight, and that it is provided with at least one inlet (19) for feeding an inert gas.

9. An apparatus according to claim 9, characterized in that the lauter tub (1) has associated therewith a pressure gas storage (13) for storing the inert gas and for recirculating the inert gas.

10. An apparatus according to at least one of the claims 7 or 8, characterized in that the lauter tub (1) is provided with a rotatably driven chopping device (2).

11. An apparatus according to claim 10, characterized in that the chopping device is adapted to be raised and lowered.

12. An apparatus according to at least one of the claims 8 to 11, characterized in that a closure element (10) is arranged in the discharge means (9) of the lauter tub (1).

13. An apparatus according to claim 12, characterized in that the opening position of said closure element is adjustable in a variable manner.

14. An apparatus according to at least one of the preceding claims, characterized in that a device (14, 15) is provided for measuring the spent grain resistance, and that a control and regulating unit is provided, which controls and regulates, respectively, the feeding of the inert gas and the excess pressure generated in the lauter tub (1) in response to the spent grain resistance.