GB2206891A - Fining process for beer - Google Patents

Abstract

An insoluble particulate material, usually a silicate, is used in conjunction with a fining agent, usually collagen or gelatin, to treat cask or other beer which contains fining agent at the point of the sale. Usually the components are premixed before being added to the beer. The sediment is reduced in volume and has increased stability to disturbance.

Description

FINING PROCESS FOR BEER The present invention relates to a process for producing fined beer in which the beer is treated with additives following fermentation to produce a sediment.

In the production of cask beers or "real ales" on completion of primary fermentation of beer in a fermentation vessel the so-called "green" beer is removed and further treated. Most of the yeast is separated from the green beer, for instance by natural sedimentation or by centrifugation. The resulting green beer contains a residual amount of yeast together with protein or other macromolecules in suspension or colloidal solution.

Generally the green beer is filled straight into the casks from which it is supplied to the consumer, although it is sometimes matured in a separate vessel before being filled into the casks. The containers from which the beer is sold to the consumer invariably contains some sediment. Storage and consumption of cask beer is almost always at a temperature well above freezing point, usually above 10 C.

zt is necessary to remove as much as possible of the residual yeast and proteins in suspension from the beer before it is consumed since cloudy beer is unsatisfactory to the consumer and suspended particles can affect the taste of the beer. The rate at which these components settle out is conventionally accelerated using finings, also known as fining agents. The most commonly used fining agent is isinglass (fish-glue), of which a major proportion is collagen. Sometimes fining auxiliaries are also used, the most common of these being silica sol materials or polysaccharides. The auxiliary is added independently of the fining agent. The fining agents major function is removal of residual yeast cells and any auxiliary's major function is the removal of dispersed protein material including fining agent.

Although the fining agents coagulate or flocculate the suspended yeast particles to produce a satisfactorily clear supernatant, the flocs they produce are often fluffy and produce a relatively low density, high volume and easily displaced sediment. This is particularly a problem when the amount of yeast is low. It is commonplace to tip casks up as they empty to remove the maximum amount of beer. If the cask is disturbed in that manner or by accident during storage the sediment tends to become resuspended in the beer within the cask and is carried over into the consumer's glass. Even if the sediment is not disturbed, its high volume has the inevitable result that a substantial amount of beer remains in the cask trapped within the network of flocs in the sediment.All these factors lead to a very high wastage of beer, or to the retailer carrying out undesirable and unhygenic practices such as fiJtering the sediments and returning the filtrate to the cask. Indeed the problem of "fluffy" sediment which can sometimes float is one of the major problems for brewers and, despite the problem having being recognised for decades or even centuries, there has been no satisfactory solution to the problem.

An entirely different way of treating green beer is the production of so-called chilled and filtered beer.

The green beer may be treated with a fining agent to remove most of the residual yeast in a conditioning tank at a low temperature, usually -1 to OOC, or at ambient temperature over a relatively long period of time. The beer is then filtered. Often a filter aid is used to improve filtration, typically diatomaceous earth or perlite, other examples being silica and silicates including sand. The filter removes flocs, yeast and colloidal protein material and the presence of very large flocs is probably an advantage in this process since such flocs are less likely to block the pores of the filter than smaller flocs.In addition to it being necessary to remove dispersed particulate matter which would otherwise make the beer cloudy, removal of protein is essential in this process since these types of beers are generally stored for long periods of time and consumed at very low temperatures at which some proteinaceous material that could pass the filter tends to form a "haze". Other components that can be used to remove the proteinaceous material which would otherwise form a haze include tannic acid, various clays such as bentonite, activated carbon and enzymes that degrade proteins. The major problems in the production of chilled and filtered beers are low filtration rates resulting from blocked filters and production of haze during storage at cold temperatures.

In GB2028340, an improved process for producing chilled and filtered beers is described in which a pre-mixed composition, comprising a filtration aid and gelatin or isinglass, is added to the conditioning tank to give an improvement in the rate of clarification and in the rate of filtration as well as a reduction in haze.

According to the present invention a new process for producing a fined-in-container beer is carried out by adding an water-insoluble particulate material and a macromolecular coagulant to fermented beer to produce a sediment.

In this specification fined-in-container beer is beer which contains fining agent in the container at the point of sale to the consumer as a result of the agent having been added after fermentation in a process in which the beer is not filtered following addition of the fining agent. This is a contrast to chilled and filtered beer which is always filtered after addition of finings.

The beer produced contains a sediment at the point of sale. In the process of the invention, therefore, the beer is not filtered after the addition of the adsorbent and macromolecular coagulant. The container can be a bottle although is usually a cask.

Usually the fermented beer to which the particulate material and coagulant are added is beer that has been removed from the fermentation vessel and from which the larger part of the yeast has been removed either by sedimentation by skimming from the surface or by centrifugation. The beer may be filled directly or via a racking tank or via a maturation vessel and a racking tank into the container usually a cask, from which it is finally sold to the consumer. The beer may be conditioned for several days in that container before the additives are added or the additives may be added as the cask is filled. Alternatively the beer may be removed from the fermentation vessel into an intermediate conditioning tank for a conditioning period following which it is filled optionally via a racking tank into the final containers. In the latter case the additives may be added to the conditioning tank either as it is filled or following part or all of the conditioning period, or they are added to the beer as it is filled into the casks or added to the racking tank or they are added to the beer after it has been filled into the casks.

By using the additives in the process of the invention we have found that there is often a large increase in the rate of removal of suspended solids by the composition and/or an improvement in the final clarity of the beer. However, the two most important characteristics are that the sediment that is produced is of lower volume than conventional sediments and is of a changed nature, i.e. is less sensitive to disturbance.

This leads to a reduction in the amount of beer which is trapped in the sediment. Furthermore the.improvement in stability of the sediment to disturbance allows the cask can easily be tipped in order to empty it without disturbing the sediment. In some instances the volume of the sediment is half or even less than half of the volume of the sediment produced using a conventional fining system.

The additives may be added to the beer independently. They may be added at the same point in the process or they may be added at different times, the particulate material being added before or after the coagulant. The additives in such processes may be added as dry materials, but preferably are each added as aqueous dispersions (suspensions or solutions). The dispersions may be supplied ready for use or, more usually may be made up immediately before use for instance by diluting more concentrated dispersions.

Sometimes the dispersions are made up from dry materials.

The particulate material may be added as a dispersion in a conventional silica sol fining anxiliary.

It is found that by far the best results are achieved if the additives are added as a premixed composition.

Although it is possible to add the composition as a mixture of dry ingredients, it is generally in the form of an aqueous dispersion containing suspended particulate material and dissolved or colloidal coagulant. The dispersion may be supplied ready for use or more usually, may be made up immediately before use for instance by diluting more concentrated dispersion, or, sometimes, by dispersing the dry materials into water.

The dispersion(s) as added to the beer preferably contains 0.05 to 10% by weight, usually up to 2% and/or 0.2 to 20% particulate material. The weight ratio of coagulant to particulate material added is preferably in the range 1:4 to 1:50, more preferably about 1:15. Concentrates for dilution prior to addition may contain up to 50% particulate material and/or up to 40%.

The or each dispersion (either the ready-for-use material or a concentrate for dilution) may be rendered storage stable, for instance by including dispersants or thickeners, or sometimes in a premixed composition the coagulant may thicken the aqueous phase sufficiently to render it storage stable. The dispersion(s) for addition to the beer may be stable only over a few days or even hours and in such cases the dispersion(s) must be made up from the components, e.g. stabilising concentrated dispersion(s) or dry material, a relatively short time before use.

The coagulant is usually supplied as a concentrated aqueous solution or colloidal dispersion although it may be supplied as dry particles. The particulate material is usually supplied in dry particulate form or as a suspension in the coagulant dispersion. To form the preferred premixed dispersion composition the ingredients are mixed together, for example by mixing them dry and then adding water, by mixing one component as a powder into a dispersion of the other component or, preferably, by mixing together two separate aqueous dispersions, optionally with other additional components. The aqueous dispersion is incubated for a period to allow it to equilibrate. During this period it is thought that the coagulant may become adsorbed onto the surface of the particulate material, at least to some extent. This equilibration period is preferably at least 15 minutes and may be more.

An alternative way of forming a pre-mixture is to supply the components as a dry blend and, usually to mix the blend with water and other optional components before use. A blend of the dry components may for instance be made by mixing finally divided particulate components, either dry or in the presence of small amounts of liquid.

The mixture may optionally be subjected to grinding. The mixture thereby produced may in some cases not require further incubation in aqueous dispersion before use, since the components may have been in sufficiently imtimate contact in the blend to equilibrate upon dispersion in water.

The macromolecular coagulant used in the composition is completely water soluble, or forms a colloidal solution in water. It may act as a flocculating agent. It may- be a synthetic polymer, for example an addition polymer formed from ethylenically unsaturated monomers, or a condensation polymer, but is preferably a natural macromolecular material or a modified natural material, since these are generally preferred for food use.

Preferred natural materials are proteins although tannic acid may be used. Proteins which are useful are generally structural proteins. Gelatin may be used although it is preferred to use collagen since it has a higher molecular weight and is therefore a more effective flocculant. The collagen may be chemically synthesised or micro-biologically produced but is generally derived from natural sources, for example mammalian sources such as animal hide. The preferred source of collagen is isinglass, which is derived from the swim bladders of fish. Collagen is usually provided in the form of a colloidal solution in acid, for instance at pH -3. The acid solubilises or "hydrolyses" the collagen. When the collagen has to be solubilised in this way it may be treated' with acid before or after being mixed with any particulate material to be used in the process of the invention.

The particulate material is water-insoluble and in particulate form in the process. It may be supplied in dry particulate form or as an aqueous dispersion. It may be a water-insoluble organic material such as cellulose or polyvinylpyrrolidone, but is generally an inorganic material, e.g. activated carbon. The preferred inorganic materials are silicaceous materials, e.g. silicates or silica. Silicates are for instance bentonites or other clays, fuller's earth, diatomite e.g. kieselguhr, perlite or other forms of silicate including zircon sand or silica flour. The adsorbents may be chemically modified, for instance acid-activated. Silica may be in the form of precipitated silicic acid or gel form for instance as a xerogel or, most preferably, a hydrogel.

The particulate material generally has low particle size. Generally substantially all, for example at least 95%, of the particles have dry sizes less than 100 microns, more preferably less than 50 microns for instance less than 40 microns. Generally most of the particles have dry sizes of at least 3 microns, preferably at least 5 microns to avoid dusting problems, although there may be small amounts of smaller particles.

The mean diameter of the particles is preferably less than 50 microns, more preferably less than 20 microns and is preferably at least 5 microns, usually at least 10 microns, for instance about 15 microns. For optimum handling properties the particles should be of a relatively uniform size.

The particulate materials used generally have pores, which for instance render them absorbent to low molecular weight proteins and the like which can affect their properties.

The coagulant is generally added to the beer in an amount of at least 5 parts per million (ppm), usually at least 10pom, preferably at least 20 ppm. It is generally not necessary to add more than 100 ppm and generally satisfactory results are achieved if the amount is less than 50 ppm. Preferred amounts of the coagulant are in the range 25 to 50 ppm.

The particulate material is generally added to the beer in an amount of at least 100 ppm, better results being achieved if the amount is at least 150. Often it may be useful to add the adsorbents in amounts of at least 250 ppm and even better results may sometimes be obtained if the amount is at least 400 ppm. In accordance with the recommendations of the authorities it is generally preferable to maintain the amount of silicate added to the beer at less than 2000 parts per million.

Preferred amounts of particulate material are in the range 150 to 1000 ppm.

The process of the invention may be used in conjunction with additions of other components such as other additions of fining agents and/or auxiliaries. Such further additives may be made either before or after addition of the composition in the new process. Other additives include enzymes to degrade any proteinaceous material remaining in the beer. In general it is found that the combination of additives used in the invention is useful to replace conventional brewery finings. When used in conjunction with an anxiliary such as a silica sol it can reduce the amount of the auxiliary needed.

The process has the effect of improving the mechanical properties of the flocs that are produced and the resultant sediment to solve the long standing problem of fluffy sediment in beer. It is surprising that the pre-incubation of the particulate material with the coagulant in the preferred process does not significantly reduce the final clarity of the beer achieved by the coagulant.

Examples The following examples illustrate the invention.

In the examples, following addition of the isinglass solution or blend, the haze in the beer (i.e. the amount of suspended material) is observed visually and noted on the scale of 0 (good) to 5 (bad) and the physical properties and amount of sediment are also noted after the period stated. The dry silica hydrogel powder used had a moisture content of about 60% w/w and consisted of particles having a mean diameter of about 15 microns with 95% having diameter of less than 40 microns. The pore size, was in the range of 8 to 10 nm with the total pore volume being more than 1 ml/g. The mean surface area was about 635 m2/g.

Example 1 Determining optimum fining action. A 1% colloidal solution of isinglass is diluted to achieve collagen concentrations ranging from 0.35% - 0.8% collagen. These solutions are added to beer at a rate ranging from 1 pint to 6 pints of collagen solution per barrel (36 gallons!.

The results are shown in Table 1.

TABLE 1 COLLAGEN CONC. SOLUTION COMPARATIVE % SEDIMENT SEDIMENT ADDITION HAZE (VOL/VOL.) PROPERTY RATE (AFTER 24 (PTS./BRL.) HOURS) Beer A 0.35% 2 5 2 Fairly Firm 3 3 2 Fairly Firm 4 1 3 Slightly Loose 5 1 5 Loose Beer B 0.5% 2 1 10 Loose 3 1 12 Very Loose 4 0 15 Extremely Loose Example 2: A 7.5% W/V. suspension of silica hydrogel is prepared and used to dilute a 1% solution of collagen to achieve a fining solution containing 5g. silica hydrogel per 100 ml. of 0.35% isinglass solution. The blend is mixed for 15 minutes. This resulting colloidal blend is used at the rate shown in the table in a range of beers and compared to a solution of 0.35% isinglass alone. The haze and sediment were observed 24 hours after addition of the compositions.The results are shown in Table 2.

Table 2 COMPOSITION RATE OF COMPARATIVE %SEDIMENT SEDIMENT ADDITION HAZE (PTS./BRL.) Beer A Isinglass Alone 4 1 3 Slightly Loose Isinglass Blend 4 0 2 Very Firm Beer B Isinglass Alone 4 0 15 Very Loose Isinglass Blend 4 0 7 Firm Example 3: Dispersions prepared in the manner of example 2, were added to glass-ended firkins. (Beer B).

Control Cask Isinglass alone was added at 4 pts./brl. Beer 'broke' i.e. flocs formed and started to settle out in 30 minutes. The flocs were very large. After 1 hour, very voluminious, fluffy sediment had settled, the top of the sediment being above the level of the tap. Numerous flocs remained in suspension. The beer was bright i.e. quite clear of suspended matter, between flocs. After 24 hours, the beer was brilliant i.e. very clear of suspended matter, and the sediment was voluminous and fluffy.

Trial Cask Isinglass hydrogel blend was added at 4 pts./brl.

Beer 'broke' in 15 minutes. The flocs were small. After 1 hour, a tight sediment had settled below the tap level, and some very small flocs remained in suspension. The beer was bright between flocs. After 24 hours, the beer was brilliant and the sediment was tight and compact, apparently occupying approximately half of the volume as in the control. Furthermore the cask could be tilted or disturbed with little or no rousing of sediment in the trial cask. A greater volume of clear beer could be drawn from the cask before any sediment began to be drawn off.

Example 4: Blends of silica and isinglass were also made by stirring 5g. dry silica hydrogel vigorously into 100 ml.

of 0.35% finings solution for 15 minutes and used for fining.

Example 5: A further blend of silica and isinglass was made by stirring vigourously 15g. dry silica hydrogel and 100 ml of a 1% aqueous solution of collagen. The concentrated dispersion was subsequently diluted with water to produce a dispersion comprising 0.35% collagen.

Claims (12)

1. A process for producing a fined-in-container beer in which a water-insoluble particulate material and a macromolecular coagulant are added to fermented beer to produce a sediment.

2. A process according to claim 1 in which yeast is first removed from the fermented beer.

3. A process according to claim 1 or claim 2 in which the particulate material and coagulants are added substantially simultaneously.

4. A process according to claim 3 in which the particulate material and coagulant are added as a premixed composition to the beer.

5. A process according to claim 4 in which the premixed composition comprises an aqueous dispersion containing dissolved coagulant and suspended particulate material.

6. A process according to any preceding claim in which the weight ratio of coagulant to particulate material is in the range. 1:4 to 1:50, preferably around 1:15.

A A process according to any preceding claim in which the coagulant is a cationic material, and is preferably a natural macromolecular material.

8. A process according to any preceding claim in which the coagulant is a protein, preferably selected from gelatin and, most preferably, collagen.

9. A process according to any preceding claim in which the particulate material is an inorganic material, preferably a silicaceous material.

10. A process according to claim 9 in which the particulate material is a silica xerogel or hydrogel.

11. A process according to any preceding claim in which the particulate material is added in an amount in the range 100 to 2,000 ppm, preferably 150 to 1,000 ppm, and/or the coagulant is added in an amount in the range 5 to 100 ppm, preferably in the range 25 to 50 ppm.

12. A process according to any preceding claim in which an auxiliary, preferably a silica sol, is also added to the beer.