DK152295B - METHOD OF FILTERING OEL - Google Patents

Description

DK 152295 B

The invention relates to a method for filtering beer in connection with the preparation thereof at the end of the post-fermentation storage period, in order to provide the beer with optimum clarity, to maximize the microorganisms present and to stabilize the beer at retention of unstable colloidal particles.

The production of beer comprises in the practical industry a final filtration step, which is intended to clear the liquid and thereby give it optimal transparency and brilliance and to a great extent remove the microorganisms present and stabilize said liquid by retaining the liquid. unstable, colloidal particles that would settle during storage.

To date, filtration agents of a mineral or cellulosic nature have been used to carry out this filtration step. The mineral nature agents are selected essentially from diatomaceous earth or diatomaceous earth, perlite and asbestos, while the cellulosic agents are selected from filter papers, cartons and randomly oriented celluloses, with only the mineral agents so far having achieved real success at the industrial and commercial levels. essentials are selected from diatomaceous earth which has been subjected to a pretreatment which in particular comprises a calcination step and a granulometric sorting step.

This diatomaceous earth actually meets the conditions set by those skilled in the art, since it does not contain, in particular, organic matter which can be carried with the liquid being filtered and has a sufficient bacteriological quality and a well-defined particle size, or it can at least as desired, is adjusted and has an irregular particle shape of the desired constituents. According to the prior art, a porous structure is ideal for filtration, delaying clogging. These filtration agents allow fully satisfying the three above-mentioned requirements for a filtering agent used for beer.

However, they present a major disadvantage which lies 2

DK 152295 B

in the extremely polluting nature of the filter cake, ie. the residue consisting of the filtering agent and those, especially organic, retained or adsorbed bodies.

In fact, this filtration residue causes severe limitations due to the pollutant nature of its organic components.

It is an object of the invention to remedy the -10 disadvantage.

It has now surprisingly and unexpectedly been found that, despite their organic nature, their size distribution, which is very far from diatomaceous earth, and their particle shape, which may be assumed in advance to be unfavorable, are starch, especially starch from root vegetables. , and especially potatoes and manioc, are not only good filtering agents for beer, but they also lead to filtering residues not being contaminated, but advantageously used for animal feed, even human food.

Thus, the filtration method of the invention is characterized in that native starch grains from root vegetables are used as the main filtration agent. For potato starch, potato and manioc starch are preferably used.

25 It should be noted that native starches are those which have not been subjected to any chemical or physical treatment, irrespective of their origin.

It is noted that from British Patent Specifications Nos. 1 082 862 and Nos. 1 113 526, it is known to use 30 starch as auxiliary in the filtration of yeast in connection with the manufacture of bakery yeast. However, there is no indication in the two mentioned citations that starch should be a suitable aid in the clear filtration of beer in the final stages of its preparation, and the fact that in yeast production a filtrate is obtained whose clarity is without significance, means that a suitability as a filter aid in yeast manufacture does not indicate any suitability for obtaining a clear filtrate in beer filtration.

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DK 152295 B

Furthermore, from a brochure from the company ALFA-LAVAL: "Beer and yeast recovery by filter" is known the use of potato starch as an alternative to diatomaceous earth as filter aid in the filtration of sludge or broths, 5 from the bottom of fermentation vessels and storage tanks in breweries. The carriers concerned are filtered using an open filter to obtain a filtrate of greatly reduced carbon dioxide content. The obtained filtrate is mixed with unpainted and unclear beer and together with it 10 undergo the remaining steps of the usual beer manufacturing process, including clear filtration. The brochure does not mention the possibility of using native starch grains as filter aid for this clear filtration. Nor can it be deduced from this brochure that starch grains from root tubers would be suitable in the method of the invention.

According to an embodiment of the method according to the invention, the filtration is carried out by means of a filter on which is applied a publisher consisting of at least 50%, preferably at least 70%, of at least one native starch, the remainder up to 100% can be used. consist of at least one filtration aid selected from the group consisting of diatomaceous earth, filtration soil and conventional filtration agents; the starch on the one hand and the filtration aid on the other hand are preferably arranged in the form of two superimposed layers so that they together form the said publisher.

According to another embodiment of said method, filtration is carried out by suspending at least one native root fruit starch, and preferably potato and manioc starch, in the beer to be filtered in sufficient quantity to prevent clogging of the filter.

The method may e.g. is carried out in a filter press or in a filter with tubular elements.

According to a further advantageous embodiment of said method, an amount of said native starch sufficient to ensure that

DK 152295 B

For example, clogging of the filter is made in suspension in the liquid to be filtered, and a filter consisting of the same starch is optionally placed on the filter, optionally mixed with at least one of the aforementioned filtration aids.

The filtration agent consists of at least one native root fruit starch, and most preferably potato or manioc starch, of a bacteriological quality compatible with its use for beer filtration, and in particular it must be free from yeast and mold.

The filtration residue can be used for animal feed and human food.

The invention is further explained in the following and in the following Examples, which are particularly directed to advantageous embodiments of the invention.

In order to achieve the desired bacteriological quality, it is sufficient to subject the starch to a prolonged storage, ie. for at least 6 months, after which live yeast and mold will no longer exist.

20 By way of example, a potato starch which had been stored for approx. one year, presented a bacteriological grade that was nearly perfect, as shown in Table I below, which lists the results of assays performed on such a starch.

Table I

Mesophilic Organ- Number in Thermophilic Number in Niche (30 ° C) 1 g 10 g Organisms 9

Aerobic bacteria 20 30 Enterobacteria 0 Spores

Col ± 0 required 10 Fecal aerobic streptococci 0 and facultative bacteria

Mold 1 35 Yeast 0 Acid-forming

Spores of CSR detect 10 (sulfur reducing)

Clostridium) 5, X „forming spores 0 5

DK 152295 B

The table shows an almost complete elimination of yeast and mold.

However, it is also possible to sterilize the potato starch without changing its grain structure more than 5 in the previous process. To do this, for example, apply a treatment with ethylene oxide or propylene oxide according to techniques known to those skilled in the art and approved in certain countries, or further by a radiation pasteurization, i. by a sterilizing treatment especially by gamma rays.

The potato starch used is made up of egg-shaped grains having a liquid content generally of 18 to 20%, the particle size distribution of which is shown in the following Table II, together with the particle size distribution of a diatomaceous earth normally used as a filtering agent. Considering Table II, how the two particle size distributions are far apart is a fact that is due to the structural differences, the diatomaceous earth particles are of irregular shapes, while the starch particles, as stated above, are egg-shaped.

It is also seen that the size distribution curve for starch has shifted towards larger particles relative to the size distribution curve of diatomaceous earth. It is further apparent from Table II that the largest starch particles are less than ca. 100 microns.

As for manioc starch, it also consists of egg-shaped grains, on the contrary, its size distribution curve is offset against the smaller grain sizes, as shown in the Table below.

Table II

Particle size x (μπι) Diatomaceous earth Starch 'Potato Manioc x <5 20% 0.3% 2.2% 5 <.x <9 36% 0.4% 2.0% 35 9 4 x <15 30% 1.3 % 38% 15 <x <25 6% 12% 52% 25 <x <40 4% 33% 5.8% 40 <x <approx. 100 4% 53% 0% 6

DK 152295 B

It will be understood that, if necessary, particular particle size fractions may be used, e.g. can be obtained by centrifugation in air (turbo separation) or by centrifugation in liquid.

In general, a pre-liner is placed on the filter, this pre-liner may consist of several superimposed layers of decreasing grain size away from the filter.

The material constituting each layer is selected from the starches whose size distribution corresponds to that required for the individual layer considered.

Thus, one after the other can have a layer of potato starch and a layer of manioc starch.

Between the potato starch layer and the filter, a layer of a filtering aid may be placed, as previously defined. It is also possible to make the publisher a mixture of filtration aid and native starch, especially potato and / or manioc starch.

The native starch publisher may be prepared by first passing a native starch suspension in a water or beer-made liquid through the said filter, the first quantities being returned in the second case to be subjected to further filtration. after the formation of the publisher.

25 The filter aid publisher can be produced in the same way.

Generally, throughout the filtration process, a suspension of the filtering agent in the beer to be filtered is continued. The amount of agent taken in suspension is selected in such a way that, for the purpose of increasing the thickness of the layer, this agent is deposited sufficiently quickly so that the said layer does not become clogged due to the retained yeast cells and colloidal substances.

35 In practice, good results are obtained by preparing a suspension of approx. 50 to 500 g, preferably 80 to 150 g of filtering agent per day. hectoliters of beer to be filtered.

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DK 152295B

Of the precipitate which continues to be formed by the filtration agent during the filtration, a filter cake is formed which e.g. consists of starch and microorganisms, a cake which advantageously applies as well as animal feed and as human food, and which is thus not a secondary product that is discardable and polluting.

The amount of additional filtration aid that may be present in this cake is sufficiently small not to be detrimental to the above use.

It can be stated that if the filtering agent is potato starch, the content of potato starch is suspended in the beer by the filtration of the order of 100 g / hl and the filtration residue consists of a mixture of starch and retained yeast cells, and the ratio of potato starch / cells is generally between 1 / 0.2 and 1/3, depending on the fermentation method chosen.

A water content of approx. 20% in the potato starch and at approx. 75% in the yeast, an average ratio of 1/1 corresponds to a dry matter ratio of approx. 1 / 0.3.

This product can be used as human food, for example after a cellular light treatment, as a flavoring agent for especially soups and sauce, and as animal feed as a component of daily nutrition, especially for pigs.

In order to illustrate the foregoing, an embodiment of the invention is given below.

Example

This Example relates to filtering beer with a potato starch filtration agent.

The filtration step found in the process of making ordinary consumer beer is carried out at the end of storage, ie. at the end of the resting step following the fermentation.

Before the filtration, the viscosity of this beer was 1.6 cp at 20 ° C (measured by a vibrating ball viscometer), the filtration temperature was between 11 and 13 ° C, the content of yeast cells was on the order of 1C5 8

DK 152295 B

cells per cell and the turbidity (which characterizes the clarity) of 0.192 (extinction value at 750 mm, a wavelength at which the color of the beer practically does not interfere with the extinction).

The filtration is performed on a filter with a filter surface of 5 cm, which flicker surface was circular and consisted of a filtering layer of cotton material specially designed for this use. The filtration pressure was 1 bar.

The amount of starch brought into suspension under the study was 100 g / hectolitre.

The filtration rate measured for the filtering surface used was 6.1 hectoliters / m / h (average calculated for a test over 4 hours).

T5 The turbidity of filtrate extracted between the 18th and 21st minutes of filtration was 0.008. This value is comparable to that of commercial beer.

Bacteriological analysis of the filtrate confirmed the absence of yeast cells.

For four starch concentrations (80, 100, 120 and 140 g / hectoliters, respectively) the curves log (filtered volume) = e.g. log (time) have been determined and these curves are found to be straight lines, confirming the absence of clogging . It is noted that by known means, such as diatomaceous earth, straight lines are also obtained.

The similarity as filtering agents between diatomaceous earth and potato starch is thus evident.

Claims (10)

A process for filtering beer in connection with its preparation at the end of the post-fermentation storage period, in order to provide the beer with optimum clarity, to remove the microorganisms present to the maximum extent and to stabilize the beer by retention of unstable colloids. -all particles, which are filtered through a closed-type filter suitable to prevent it from escaping into the beer ”• 0, resulting from fermentation gas, characterized by using native starch grains from root vegetables as the main filtration agent. Process according to claim 1, characterized in that the starch is potato starch. Process according to claim 1, characterized in that the starch is manioc starch. Process according to claim 1, characterized in that a mixture of different starches is used. Process according to any one of the preceding claims, characterized in that before the beer is fed to the filter, a layer consisting of at least 50%, preferably at least 70%, of at least one native is deposited thereon. starch, while the remainder up to 100% consists of at least one filter aid, preferably selected from diatomaceous earth and filtration soil, the starch and the other filter aid being preferably arranged in the form of two adjacent layers. Process according to any of claims 30 1-5, characterized in that a sufficient amount of starch is suspended in the beer to be filtered to avoid clogging of the filter. Process according to claim 5 or 6, characterized in that several superimposed layers are deposited on the filter, the grain size of which decreases away from the filter, the material constituting each layer being selected from starches. , whose grain size distribution curve corresponds to that required for each of the layers in question. Method according to claim 7, characterized in that a layer of potato starch is first deposited and then a layer of manioc starch. 9. A method according to claims 5-8, characterized in that a layer of at least one non-starch filter aid is arranged between the filter and the first layer of starch on the filter. Process according to claims 5-9, characterized in that in the beer a quantity of starch ranging from 50-500, preferably 80 to 15 150 g / hectoliters, is suspended.