SI9820005A - Method for producing cold-filtered beer - Google Patents

Abstract

The invention relates to a method for producing cold-filtered beer. According to said method, beer is filtered through a membrane filter which is able to absorb calcium ions. After filtration, said membrane filter is cleaned and rinsed with aqueous substances. The washed and rinsed membrane filter can then be reused. The invention is characterised in that an acidic aqueous substance with a pH less than 5.0 is used for rinsing, or in that the substance used for rinsing is treated in order to reduce the quantity of calcium ions it contains. The inventive method provides a means of producing beer with less tendency to gush.

Description

BRAU-UNION Osterreich Aktiengesellschaft

Process for the preparation of cold filtered beer

The present invention relates to a process for the preparation of cold filtered beer, whereby the beer is filtered through a membrane filter that can absorb calcium ions, and after filtration it is purified and washed with aqueous media, and then the purified and washed membrane filter is used for new filtration.

Beer has to be disinfected because of its long sales routes in order to be able to store it. Today, disinfecting beer is primarily pasteurized. For this beer stuffed e.g. in bottles or cans, heated to a temperature between 62 and 68 ° C, thus destroying the germs.

However, this pasteurizing consumes a lot of energy. Furthermore, it has the disadvantage that the energy supplied can trigger chemical reactions that degrade the product and which are only difficult to control. Due to these reactions, e.g. the taste of the product changes unfavorably (Pasteur's taste) and there is also the risk of the formation of unwanted substances. Pasteurization is, therefore, a relatively expensive disinfecting process that consumes a lot of energy and therefore burdens the environment and reduces quality.

A further disinfection process is cold filtration through membrane filters. Cold filtered beers offer e.g. in the United States, Japan, and Korea as t.i. draft beers. In Europe, these beers are banned because they contain technical enzymes. These technical enzymes counteract the disadvantage of cold filtration inherent in this technique: rapid filter clogging. This clogging is attributed to the sedimentation of beer-filtered substances on the membrane filter side upstream. Sediments are only difficult to remove or can no longer be removed from the filter and reduce the filter life. This increases the cost of beer production because membrane filters are expensive.

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In order to increase the filter life, membrane filter makers recommend that the membranes used be cleaned by treatment with proteases, glucanases and xylanases as well as chemicals such as surfactants, acids / bases and oxidizing agents, thus making them suitable for use again. This cleaning may e.g. it proceeds in two stages, the first stage being purified with said enzymes and then optionally with the specified chemicals.

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As an example, it envisages a cleaning process e.g. at a filter surface of about 320 m, at a filtration rate of 5,000 hectoliters (hi) each year, enzymatic purification and 20000 hi each additional dry cleaning. The typical life span of such purified filters with a filter area of about 320 m ² is about 100,000 hi.

Many types of membrane filters, after being subjected to the first purification process, are known to filter beer directly after purification, which, when bottled or bottled, tends to so-called. gushing.

The term gushing is known for spontaneous pouring of beer when opening a bottle or. cans. This results in the sudden release of carbon dioxide, which is accompanied by a strong foam formation that results in a more or less strong emptying of the bottle or. cans. It is on the palm of the hand that consumers tend to think of gushing as a product defect that can lead to serious economic disadvantages for the brewer.

The exact cause of the onset of gushing is unknown. It is alleged that it is gushing in relation to the raw materials used to make the beer. Like you. gushing promoters are considered to be lower molecular compounds, e.g. fatty acids, bitter hops, polypeptides, oxalic acid and fungal infections. It is further known that membrane filtration can reduce the tendency for gushing. However, membrane filters with different pore sizes lead to different results.

In the experience of the applicant, the tendency for gushing is particularly pronounced in beers that are filtered through certain freshly purified membrane filters. This is especially pronounced for membrane filters that are at least partly made of polyamide. Therefore, it is an object of the invention to provide at p / lz / 2684 lpr.doc a process for the preparation of cold filtered beer, which is filtered through membrane filters and, nevertheless, the tendency of gushing beer to be filtered directly after the purification process is at least reduced.

The process of the invention for the preparation of cold filtered beer, in which the beer is filtered through a membrane filter that can absorb calcium ions and after filtration is cleaned and washed with aqueous media, and then the purified and washed membrane filter is used for new filtration, to use an acidic aqueous medium having a pH of less than 5.0 or to undergo treatment to reduce the calcium ion content.

The invention is based on the realization that the tendency to gushing is particularly pronounced when beer is filtered through a membrane filter that can absorb calcium ions. This is e.g. an example where the filter is at least partly made of polyamide. If such a filter is rinsed after cleaning with an aqueous medium, e.g. tap water containing calcium ions is absorbed so that the filter is coated with calcium ions. If such a calcium ion-coated filter is used to filter the beer again, these calcium ions are released from the filter at the start of the filtration due to the acidic pH of the beer to be filtered. So these calcium ions get into the beer. The Applicant considers that the released calcium ions with carboxylate ions, e.g. The oxalates present in the beer form fine crystals, which act as pellets to form gas CO ₂ bubbles.

It has now emerged that the tendency for gushing should be attributed to the initial release of calcium ions from freshly purified filters. The acidic wash according to the invention therefore serves to rinse the calcium ions absorbed by the membrane filter during the purification process.

If aqueous media are used for cleaning and washing, they are subjected to treatment to reduce the calcium ion content, ie decalcification, e.g. with ion exchangers, no acidic washing according to the invention is required. Even in this case, the beer filtered through a freshly cleaned filter shows no tendency to gushing.

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An acidic aqueous medium has a pH of less than 4.5, preferably between 3.0 and 4.0, and especially less than 3.5.

Useful organic acid, especially lactic acid, is used to adjust the pH.

The invention further relates to a process for the preparation of cold filtered beer, whereby beer made from malt, hops and water is subjected to membrane filtration and is characterized by the use of water which has been subjected to treatment to reduce the calcium content of beer ions.

The invention can be carried out on all calcium ion-binding membrane filters. This is an example, for example. with a membrane filter that is at least partly made up of polyamide. The polymer is believed to have free carboxylate groups or similar reactive groups that can bind calcium ions.

The invention will be described in further detail below.

For membrane filtration, we used a polyamide membrane filter commonly used in the art. After filtration, the filter was first purified enzymatically and then chemically as follows.

For enzymatic purification, the clogged filter was treated for 1 hour with a 1% aqueous solution of a mixture of beta-glucanases and xylanases (P3-Ultrasil 65; manufacturer: Henkel) with pH 5 (adjusted with a 0.05% aqueous solution of the surfactant mixture and acidic components (P3-Ultrasil 75; manufacturer: Henkel) at 50 ° C. This treatment was then repeated.

The filter was then treated with a 0.5% aqueous solution of a mixture of surfactants, glucanases and proteases (P3-Ultrasil 62; manufacturer: Henkel) with a pH of 9-9.5 (adjusted with 0.15% aqueous solution of a mixture of surfactants and alkaline components (P3-Ultrasil 91;

p / lz / 26841pr.doc manufacturer: Henkel) for 3 hours at 50 ° C and then rinsed with tap water (50 ° C).

For dry cleaning, the filter was treated with a 1% aqueous solution of a mixture of surfactants and acidic component (P3-Ultrasil 75; manufacturer: Henkel) for 30 minutes at 60 ° C and then washed with fresh tap water. The filter was then treated with an aqueous solution containing 1% surfactant and alkaline component mixture (P3-Ultrasil 91; manufacturer Henkel) and 1% surfactant and oxygen donor mixture (P3-Ultrasil 0.5; manufacturer: Henkel) for 30 minutes. at 60 ° C and then rinsed with fresh tap water. The filter was then treated again with a 0.5% aqueous solution of a mixture of surfactants and acidic component (P3-Ultrasil 75; manufacturer: Henkel) for 30 minutes and then rinsed with fresh tap water until the rinsing water reached electrical conductivity fresh water.

The water used to clean and rinse the membrane filter used was non-decalcified tap water.

The beer, which we initially filtered through this membrane filter, purified by water, was shown to have a tendency to gushing. Only from the amount of filtrate of about 0.8 h of beer per m ^{2 of} filter surface, when the calcium release was complete, we were able to filter the beer again without the tendency to gushing.

If the same filter, purified by the above procedure, was washed with water, which was brought to pH 4.5 with the addition of lactic acid, it was shown that the rinsing water was enriched with calcium ions, which apparently originated from a freshly cleaned membrane filter. The beer filtered through this membrane filter washed with acidic rinse water had no tendency to gushing.

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The same effect could be observed if decalcified water was used for cleaning and rinsing.

For

BRAU-UNION Osterreich

Aktiengesells

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WRITERS 4.0.0. ANA, CHOPOVA 14 β

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Claims (7)

PATENT APPLICATIONS A process for the preparation of cold filtered beer, in which the beer is filtered through a membrane filter capable of absorbing calcium ions and after being filtered cleaned and rinsed with aqueous media, after which the purified and washed membrane filter is used for new filtration, characterized in that Wash using an acidic aqueous medium having a pH of less than 5.0 or undergo treatment to reduce the calcium ion content. A process according to claim 1, characterized in that the acidic aqueous medium has a pH of less than 4.5. Process according to one of Claims 1 or 2, characterized in that the aqueous medium has a pH between 3.0 and 4.0, especially less than 3.5. Process according to one of Claims 1 to 3, characterized in that it contains an acidic aqueous medium used for washing, an organic acid. Process according to claim 4, characterized in that the acid contained in the acidic aqueous medium is lactic acid. 6. A process for the preparation of cold filtered beer, subjecting beer made from malt, hops and water to membrane filtration, characterized in that water is used to prepare the beer which has been subjected to treatment to reduce the calcium ion content. Method according to one of Claims 1 to 6, characterized in that a membrane filter consisting at least partially of polyamide is used.