GB2182672A

GB2182672A - Process and apparatus for continuous energy saving hop cooking

Info

Publication number: GB2182672A
Application number: GB08612258A
Authority: GB
Inventors: Peter Ullmann; Istvan Marjai; Gyorgy Bendek; Imre Horvath
Original assignee: KOBANYAI SORGYAR
Current assignee: KOBANYAI SORGYAR
Priority date: 1985-06-03
Filing date: 1986-05-20
Publication date: 1987-05-20
Also published as: DD244989A5; GB8612258D0; GB2182672B; DE3614431A1; FR2582668B1; FR2582668A1; HU195243B; CS407486A2; ATA120286A; AT386605B; HUT41064A

Abstract

A process and an apparatus are described for boiling beer wort in which incoming wort from the mashing stage is heated in a heat exchanger (1) by boiled wort leaving the apparatus through a second pressure reducer (7). The wort is heated still further in vessels (2 and 3) by steam from first and second pressure reducers (6 and 7) and finally it is heated by fresh steam in a pressure vessel (4) to 120 DEG to 125 DEG where it is kept for 1 DIVIDED 2 to 2 minutes. It is then fed through a series of pressure reducers; in the illustrated embodiment two reducers (6 and 7) are shown and in the penultimate reducer (6) the wort is kept for 20 to 40 minutes. The process of the present invention provides saving in heat as compared to traditional and more modern hop cooking processes. <IMAGE>

Description

SPECIFICATION Process and apparatus for continuous energy saving hop cooking The invention relates to a process and apparatus for continuous energy saving hop cooking.

When boiling the beerwort (hop cooking), highly complex processes take piace yielding in -solution and isomerisation of the bitter materials of hop, -coagulation of proteins, - leaving of undesirable aromatic materials, - increasing the concentration of beer wort by evaporation of water, -forming of reducing and aroma materials, ceasing of the activity of still active enzymes, - sterilisation of beer wort.

The so-called traditional hop cooking, that is, cooking at atmospheric pressure, perfectly meets these requirements yielding the best quality beer extract, but it also has disadvantages, namely that it is an intermittent, time consuming process and the main disadvantage of it is the high energy requirement, as cooking of I hliter beer wort requires 1520 kg steam.

Different continuous technologies have been developed recently for improving the efficiency of the process and saving heat energy. The German "Offenlegungsschrift" No. 1 091 516 describes a process according to which the beer wort is heated up to 130--150"C, then it is maintained at this temperature for 34 minutes. Thereafter the pressure of the beer wort is suddenly but steeply decreased and the steam formed due to this decrease is used for preheating the incoming beer wort. Thus, a large part of the heat energy can be kept within a cycle and fresh steam (primary energy) must only be used at the final step when the beer wort is heated up to 130--1500C.

This process results in rapid protein-coagulation, efficient izomerisation of bitter materials and in significant energy saving but the taste of the beer is not as good as that of the beers boiled according to the traditional method and more complicated and expensive heat supplying apparatus must be used, due to the high temperature and steam pressure. It is also disadvantageous that the brewery must often be stopped so as to remove the continuously forming deposit.

According to the German patent specification No.

3.336.310 the deterioration of taste, caused by the evaporation at high temperature, can be prevented if a pressure reducer, so-called pre-vaporator is mounted into the beer wort preheating system after the step where the temperature surpasses 1 00 C, but before the high temperature step where fresh steam is applied. Thus, the taste deteriorating agents are eliminated at a sufficiently low temperature. It is another advantage of th is process that a higher rate of evaporation can be realized.

Nevertheless, presuming identicai holding temperature, the energy requirement of this process is higher than that of the continuous technology not applying intermediate pressure reducer.

The present invention is aimed at developing a novel continuous energy saving hop cooking process which makes possible the production of beers of traditional quality.

The invention is based on the recognition that beers, perfectly equal in quality to those made traditionally, can be made using less energy if the beer wort is heated up to a significantly lower temperature than usual at the warmest step where fresh steam is applied, if the holding following this step is significantly shorter than usual, if the residence time of beer wort at the penultimate pressure reducer is significantly increased and if the beerwortis led back to the beginning of the preheating system, where it is used for preheating the incoming beer wort in a regenerative heat exchanger, so as to utilize the heat content of the leaving beer wort.

On the basis of the above the invention relates to an improved process for continuous energy saving cooking of beerwort by preheating the beerwort in several steps, heating up the beer wort to the highest temperature applying fresh steam in the final stage, the stepwise pressure reduction of the beer wort and the utilization of the heat content of the steam, evaporating during the pressure reduction, in the preheaters.The improvement consists in heating the beerwort up to 12S125 C in the final heating stage, holding it at this temperature for 0.52 minutes, ensuring a residence time of 2040 minutes of the beer wort in the penultimate pressure reducer of pressure reducers connected in series and preheating the incoming beer wort in a regenerative heat exchanger with the beerwort leaving the last pressure reducer.

The invention relates further to an apparatus for carrying out the above process. The apparatus comprises steam/liquid heat exchangers connected in series, a fresh steam-heated final stage and pressure reducers which are connected to the heat exchangers by pipes. The novelty of the apparatus resides in a regenerative heat exchanger mounted before the heating steam/liquid heat exchangers, a side of said regenerative heat exchanger being connected to the pipe of the incoming beer wort and the other side thereof being connected to the fluid outlet junction of the last pressure reducer.

The invention is described in more detail by taking reference to Figure 1. According to Figure 1, the beer wort incoming from the intermittent-duty mash filter or from the continuous mash filtering and extracting unit or from a receiver, the temperature of which is about 7073 C, is pumped continuously with the help of a pump of controlled capacity to the regenerative heat exchanger 1 where the beer wort is heated up to 80"C. Afterwards the beer wort goes to the first steam/liquid heat exchanger 2, where it is heated up to 8090 C by the steam coming from the second pressure reducer 7. In the next step, the beer wort is heated up to 90--1 1 0 C in the second steam/liquid heat exchanger 3 which utilizes the steam coming from the first pressure reducer 6.The next step is the step of the highest temperature, namely the fresh steam/liquid heat exchanger 4, where the beerwortis heated up to 120--125"C.

From here the beer wort goes to the holding unit 5, where it is held for 0.5--2 minutes, preferably for 1 minute, on 120--125"C. The beer wort coming out from the holding unit goes into the first pressure reducer 6. (The apparatus of Figure 1 includes only two pressure reducing steps so the first pressure reducer is also the penultimate one.) The beer wort stays for 2040 minutes in the pressure reducer 6, so the slow evaporation taking place here can be regarded as a second hop cooking. The temperature of the beer wort is lowered to 1 01 1000 in the meantime. The beer wort cools back to 10000 in the second pressure reducer 7.From here the beer wort is led back to the regenerative heat exchanger being at the beginning of the preheating system where it preheats the incoming beer wort and cools back to 858900 and goes further in the brewing process with this temperature.

The main advantages of the invention are as follows: Heating the beer wort up to 120--1250C in the highest temperature stage and the 0.52 minutes of holding proved to be perfectly satisfactory so there is no need for heating the beer wort up to 15000 and holding this temperature for 34 minutes, which treatments only deteriorate the aroma materials.

The holding time of 20--40 minutes at 103--1100C in the penultimate pressure reducer (the known process describes 34 minutes of holding at 12-134"C) results in more efficient isomerisation of the bitter materials. The quality of the beers prepared by the process of the invention is the same as the quality of those made according to the traditional process. Due to the lower temperature and the regenerative heat exchanger not applied so far, the process of the invention requires much less energy.According to our related calculations the energy requirement of the process of the invention is only 25% comparing to that of the traditional hop cooking process (cooking at atmospheric pressure), while the continuous hop cooking process being known so far, when applying 34 minutes of holding at 130150 C and utilizing the steam coming from the pressure reducer, required as much as 3335% of the energy required by the traditional process. It is an additional advantage that the apparatus of the invention can be more simple because of the lower temperature and pressure applied; it is also widely known that costs of apparatus working with fluids under pressure grow exponentially with the pressure applied. Because of the shorter holding time, the holding unit, which is generally a coil pipe can be made shorter, which is another additional advantage.

Claims

1. A process for continuous energy saving hop cooking bystepwise preheating of the beer wort, heating up the beerwortto the final, highest temperature with fresh steam, reducing stepwise the pressure and utilizing the heat content of the evaporating steam in the preheating units, characterized by heating the beer wort up to 120--125"C at the highest temperature stage, holding it at this temperature for 0.52 minutes, ensuring a residence time of 20--40 minutes in the penultimate pressure reducer of pressure reducers connected in series and preheating the incoming beer wort in a regenerative heat exchanger with the beer wort leaving the last pressure reducer.

2. Apparatus for carrying out the process of claim 1, including steam/fluid heat exchangers and connected in series, a final stage heated by fresh steam, and pressure reducers and connected with the heat exchangers and by pipes, characterized in that a regenerative heat exchanger is arranged before the preheating steam/fluid exchangers and one side of said regenerative heat exchanger being connected to the pipe of incoming beer wort and the other side thereof being connected to the fluid outlet junction of the last pressure reducer (7).

3. A process as claimed in claim 1, substantially as hereinbefore described in conjunction with Figure 1 of the accompanying drawing.

4. An apparatus substantially as hereinbefore described in connection with, and as shown, in the accompanying drawing.