HOME BREW ADDITIVES AND METHOD OF USE

FIELD OF THE INVENTION This invention relates to home made beer and, in particular, to making beer with an acceptable head.

INCORPORATION BY REFERENCE

This patent application claims priority from:

- AU 2007905739 titled "Home brew additives and method of use" filed on 19 October 2007. The entire content of this application is hereby incorporated by reference.

BACKGROUND TO THE INVENTION

Making beer at home for personal use is a popular past time and undertaken all over the world. Many varieties of beer are available for making at home, and many of those who make beer use home brew kits (otherwise known as micro brew kits) which are readily available from many sources. The kits typically include instructions and most of the ingredients to allow the kit user to ferment their own batch of beer.

Some enthusiasts are able to not only ferment their own beer but are also able to create the starter wort by selecting a suitable grain (ie barley, wheat, etc), germinating the grain by steeping malted grain in hot water during a process called mashing, heating the mash in a process known as lautering to deactivate the enzymes and sparging the wort by adding water to extract sugars. The wort generated by that process is collected in the kettle where it is boiled and has hops added at predetermined times as well as other optional ingredients that will affect the taste, head, clarity, colour and aroma of the final product. This process is called kettling. The product is then in either a liquid or dry state and known as concentrated wort or malt extract.

Typically, the home beer maker buys a concentrated form of wort in a kit (wherein the wort is typically provided in liquid form in a sealed can), or can otherwise purchase the other essential ingredients to allow them to primary ferment the wort by adding pre-soaked yeast (pitching the yeast), carbohydrates (typically brewers sugar) and hot water to the wort. Instructions as to the order and timing of the steps to create the primary fermentation are supplied with the kit and some home brew makers use variations as well as adding compounds and essences that are intended to affect the final taste, aroma and other characteristics of the beer produced.

Home beer making kits and their instructions are not a scaled down version of the commercial beer making ingredients or process. The smaller quantities and more variable fermentation conditions require that the creator of a home brew kit carefully select the ingredients that, although similar to the commercial ingredients, are not the same. That is, they can vary in subtle ways and in some cases a substitute is used that would not be suitable in a commercial making arrangement or process. By way of

example, taking the exact ingredients used in the commercial making of a beer but using home brewing processes and equipment to ferment those ingredients, will not produce a beer of the same standard, taste, aroma and other characteristics of the commercial beer product. There is a great deal of experimentation associated with choosing the ingredients for a home beer making kit. Thus, when a brewery makes the wort for a home brew kit that is designed to produce a particular type of beer or beer style, the ingredients they use in the creation of that wort are different to those that would be used if they were commercially producing the wort for that same type/style of beer for commercial consumption.

The primary fermentation ingredients are supplied in a home brew kit in an air-tight container and once opened and added to appropriate further ingredients (including yeast, hot water and carbohydrate), the yeast ferments the carbohydrate in the mixture in an air-locked fermenter which is kept within an appropriate temperature range until the additional carbohydrate as well as those present in the wort are fermented to alcohol and other compounds. The completion of the primary fermentation can be confirmed by measuring the alcohol concentration of the brew by a specific gravity measure, which is compared to the expected concentration of alcohol from the complete conversion of all carbohydrates to alcohol or other by-products of alcoholic fermentation. The result is a "flat" or non-carbonated beer that lacks the aesthetic qualities associated with effervescence and an acceptable beer head. While keg carbonation of the primary fermented beer is often utilised in a commercial setting, a more desirable option for the carbonation of home brewed beer is to conduct a secondary fermentation of the beer primarily for CO ₂ production.

Secondary fermentation is preferably conducted within the bottle from which the beer is to be consumed and that is achieved by placing a portion of the resulting brew liquid in a bottle to which the beer maker adds a measured amount of priming sugar to each bottle and caps it. The cap creates an air-tight seal to prevent the ingress of air and the egress of CO ₂ which is desirably maintained in solution, at least in part. Alternatively, the mixture can be bulk primed by adding a bulk amount of priming sugar to the brew contained within a similarly sized container to that in which the brew was contained after or before adding the primary fermented beer from the fermenting container, and thereafter pouring the primed brew into bottles from this second container. The first brew is carefully drained from the fermenting container to lessen the amount of settled yeast and other solids entering the beer to be consumed and the secondary fermentation is conducted in a similar manner within the bottle. Some weeks (preferably, for many beer drinkers, the period is some months) thereafter, the bottled beer is ready to consume as the secondary fermentation is complete.

The taste, mouth feel and aroma that the beer takes from its ingredients and the beer making process is greatly improved from the beer resulting from a primary fermentation alone, and can then hopefully be enjoyed by its maker.

There are many characteristics that define a beer and all beer drinkers weigh each of them differently when it comes to determining their liking for one beer over another. One of those characteristics is "head retention" which is measured by the time it takes for a predetermined depth of head to dissipate. For many beer drinkers, the quicker the head dissipates, the worse the beer since, interestingly, the taste of beer is not only constituted by the taste and after taste of the liquid component, but also the texture and pre- and after-taste of the head of the beer being enjoyed by the drinker.

The head itself is made up primarily of bubbled gases but the longevity of the head is dependent on the make up of the bubbles themselves which needs to be of low surface tension and it is known that primary contributors to that characteristic are high molecular weight proteins derived from the grains selected in preparing the wort.

The home brew maker that uses a kit has to rely on the supplied starter wort and brewers sugar (particularly those with malts and malto-dextrin) to determine what type of head retention the final beer brew will have. It is also important to use clean drinking glasses that do not have soapy residue on their surface as that will reduce the foam retention dramatically. Further, the shape of the drinking glass can also help to promote the creation of the head and enhance head retention.

Those home brewers that make their own starter wort can choose one or more malted grains that are known to improve head retention (ie wheat, crystal grain, etc). However, the type of beer they eventually produce is then limited by the type of grain used and inappropriate use (ie too much or too little) and which if not in balance with other ingredients, can have other deleterious effects on the characteristics of the final beer product.

There are a number of other techniques available to the home brew maker such as adding certain heading agents including starches, enzymes, herbs and spices which are used at different times during the primary fermentation process.

Commercial brewers (a brewer is traditionally considered to be the person responsible for the making of the wort which is distinguished from those that supervise the fermentation process), produce wort in highly controlled and repeatable conditions. Brewers carefully select their ingredients and have control of the addition of those ingredients and process that will affect head retention characteristics, this being one of many other characteristics. Choice of the ingredients and any additives to promote head retention, particularly for the wort brewing stage, is a complex undertaking.

The present invention provides a new way of controlling the head of beer made in a home beer making environment or at least provides an alternative.

SUMMARY OF THE INVENTION

According to a first aspect, the present invention provides a home brew beer additive for improving beer head retention comprising tetrahydro iso-α-acid and/or hexahydro iso-α-acid and a priming sugar, wherein said priming sugar acts as a bulking agent of said home brew beer additive for dosing a volume of wort or beer with said tetrahydro iso-α-acid and/or hexahydro iso-α-acid.

In a second aspect, the present invention provides a beer head retention additive for use at the stage of secondary fermentation of a beer mixture comprising a boiled sugar element comprising terra hop.

In a third aspect, the present invention provides a method for making home brewed beer, said method comprising: pitching a volume of beer wort with a starter culture of yeast; allowing the volume of beer wort to ferment; and adding an amount of tetrahydro iso-α-acid and/or hexahydro iso-α-acid to improve beer head retention; wherein said tetrahydro iso-α-acid and/or hexahydro iso-α-acid is optionally added in combination with an amount of priming sugar for priming a secondary fermentation of said fermented volume of beer wort.

In a fourth aspect, the present invention provides a use of a beer head retention additive in a secondary fermentation of beer in a container comprising: combining a boiled sugar element having a predetermined amount of tetra hop with a beer mixture to promote a secondary fermentation phase in the beer mixture.

In a fifth aspect, the present invention provides a kit for making home brewed beer comprising a fermenter for conducting a primary fermentation therein, a home brew wort concentrate, a beer brewing yeast starter culture, and a home brew beer additive comprising tetrahydro iso-α-acid and/or hexahydro iso-α-acid.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 illustrates (a) a plastic fermenter and lid for brewing the home brew therein with an adhesive thermometer strip affixed thereto; and (b) an airlock half filled with water.

DETAILED DESCRIPTION OF THE INVENTION

Throughout the following description it is considered that persons skilled in the art could readily source or generate wort required for brewing beer, for example by simply rehydrating a commercially available wort concentrate in accordance with manufacturer's instructions (eg Lager Concentrate available either in a home brew kit or as a single item available for purchase from Coopers Brewery Limited, Regency Park, SA, Australia) or by making wort from grains and hops according to methods well known in the art.

According to a first aspect, the present invention provides a home brew beer additive for improving beer head retention comprising tetrahydro iso-α-acid and/or hexahydro iso-α-acid and a priming sugar, wherein said priming sugar acts as a bulking agent of said home brew beer additive for dosing a volume of wort or beer with said tetrahydro iso-α-acid and/or hexahydro iso-α-acid.

Hops have long been an integral component of the beer making process contributing greatly to the characteristic bitter flavour of beer. Hops contain α-acids and β-acids which are predominantly responsible for the bittering of beer. The process of boiling leaf hops during the kettling process of wort production causes the isomerisation of α-acids to form iso-α-acids, these derivative forms of α-acids are more intensely bitter than their non-isomerised counterparts are more soluble and stable in beer.

Certain derivatives of iso-α-acids, such as tetrahydro iso-α-acid and hexahydro iso-α-acid, are more stable and, accordingly, provide a highly concentrated form of hops additive. Tetrahydro iso-α-acids may be derived from α-acids, for instance by isomerising hydrogenated α-acids into tetrahydro iso-α-acids or by hydrogenation of iso-α-acids. Tetrahydro iso-α-acids, when added at certain stages of the brewing process, can act as a concentrated foaming agent and can improve beer head retention.

While iso-α-acids and rho iso-α-acids may be used as additives to enhance beer bittering, they have little effect on beer foaming and beer head retention. However, tetrahydro iso-α-acid and hexahydro iso-α-acid attribute bitter flavour qualities as well as improving beer head retention. Tetrahydro iso-α-acid is more effective than hexahydro iso-α-acid in improving beer head retention, accordingly, a preferred home brew beer additive according to the first aspect, comprises a tetrahydro iso-α-acid.

As used herein, the term "tetrahydro iso-α-acid" is to be understood as referring to a substantially pure preparation (ie consisting of a single type of tetrahydro iso-α-acid) or a mixture of tetrahydro iso-α-acids. Similarly, the term "hexahydro iso-α-acid" is to be understood as referring to a substantially pure preparation (ie consisting of a single type of hexahydro iso-α-acid) or a mixture of hexahydro iso-α-acids.

Hops products comprising tetrahydro iso-α-acids for use in beer production, commonly known as "tetra hop", are commercially available, for example as YC-Tetra (Yakima Chief Inc, Yakima Valley, WA, United States of America) and Hopsteiner (S S Steiner Inc, New York, New York, United States of America). Such products are common additives in commercial beer production and are known to provide optimum bittering and foaming when incorporated into the production process following fermentation.

Tetra hop is generally incorporated into the brew following the primary fermentation stage as the gasses formed during fermentation lead to the excessive foaming of brews containing tetra hop. This, in turn, can cause substantial loss of beer from overflow as well as the loss of foaming agents which tend to reside in the upper foam layer of the brew.

Tetra hop is suited to use in commercial beer production as only small amounts are required to provide optimal bittering and head retention. Overdosing can easily spoil beer flavour and lead to excessive foaming. The difficulties associated with providing optimal concentrations of tetra hop in smaller volume brews, such as home brews, has impeded the use of such additives in these settings. In particular, the use of tetra hop in the traditional unfiltered home brew, which utilises a secondary fermentation within the bottle for carbonation, poses particular dosing difficulties. To prime the secondary fermentation, a small amount of simple sugars must be dissolved within the beer, which is usually then bottled to create an airtight seal. To avoid agitating the thick sediment formed during the primary fermentation, priming sugars are frequently added to the bottled beer rather than to the primary fermenter. This, further, prevents the need to filter the beer prior to bottling.

By incorporating iso-α-acid into home brew priming sugar, it has been surprisingly found that the bulking effect of the priming sugar could regulate the dosing of iso-α-acid in small volume brews, such as home brews, so that the beneficial flavour and beer head foaming effects could be achieved in a home brewed beer.

Particularly suitable sugars for priming home brew secondary fermentations include simple sugars.

Accordingly, a preferred home brew beer additive according to the first aspect comprises a monosaccharide priming sugar (eg glucose and/or dextrose) and/or disaccharide priming sugar (eg sucrose and/or fructose).

The concentration of priming sugar provided at the secondary fermentation stage must be adequate to ensure that sufficient CO ₂ is produced as a by-product of fermentation to carbonate the beer although, as the beer is maintained under pressure to prevent the loss of dissolved CO ₂ , concentrations of priming sugar that are too great may cause the build-up of CO ₂ and eventually the explosion of the beer bottle.

As the suitable concentration of priming sugar may also vary depending on the type of sugar provided as the priming sugar, a preferred home brew beer additive according to the first aspect comprises tetrahydro iso-α-acid and/or hexahydro iso-α-acid and priming sugar in a ratio of about 1 :500 (by weight) to about 1 :20,000 (by weight), more preferably about 1 : 1000 (by weight) to about 1 : 10,000 (by weight), even more preferably about 1 :2000 (by weight) to about 1 : 8000 (by weight), and most preferably about 1 :4000 (by weight).

While any type of sealable container may be suitable for conducting a secondary fermentation, bottles containing a volume of beer between 330ml to 1500ml are most commonly utilised (eg "stubbies" of 330ml or 375ml, "longnecks" of 750ml or "magnums" of 1500ml are commonly utilised).

A home brew beer additive according to the first aspect preferably comprises tetrahydro iso-α-acid and/or hexahydro iso-α-acid in an amount within the range of about 0.0005% (by weight) and about 2% (by weight) and said priming sugar in an amount within the range of about 0.5g and 2Og. More preferably, a home brew beer additive according to the first aspect comprises tetrahydro iso-α-acid and/or hexahydro iso-α-acid in an amount within the range of about 0.005% (by weight) and about 0.2% (by weight) and said priming sugar in an amount within the range of about 2g and 1Og. As the most commonly utilised beer volumes are multiples of the smallest volume, ie 375ml, the most preferable amount of tetrahydro iso-α-acid and/or hexahydro iso-α-acid is about 0.025% (by weight) with an amount of priming sugar about 4g. Said home brew beer additive comprising about 0.025% (by weight) tetrahydro iso-α-acid and/or hexahydro iso-α-acid and about 4g priming sugar may be formed in discrete dosage units whereby one unit is added to about a 330ml-375ml volume, two units are added to about a 660ml-750ml volume of beer and four units are added to about a 1320ml- 1500ml volume of beer.

A single dosage unit may be provided as a boiled sugar element or sugar "drop" (also known as

"carbodrops"). A preferred home brew beer additive according to the first aspect may therefore comprise a boiled sugar element comprising a hops extract, particularly comprising tetrahydro iso-α-acid and/or hexahydro iso-α-acid, more preferably tetrahydro iso-α-acid and, most preferably, tetra hop.

Preferably, a single dosage unit comprises a tetra hop in an amount within the range of about 0.005% (by weight) and about 20% (by weight) and priming sugar in an amount within the range of about 0.5g and 2Og. More preferably, a single dosage unit comprises tetra hop in an amount within the range of about

0.05% (by weight) and about 2% and said priming sugar at an amount within the range of about 2g and 1Og. Most preferably, a single dosage unit comprises an amount of terra hop of about 0.25% (by weight) and about 4g of priming sugar.

A single dosage unit of home brew beer additive according to the first aspect may be provided in a sachet in powdered, crystalline or liquid form or as a combination thereof. Preferably, the primer sugar is provided as a solid boiled sugar element (optionally produced according to the steps outlined below) comprising tetrahydro iso-α-acid and/or hexahydro iso-α-acid, preferably tetrahydro iso-α-acid, and more preferably terra hop. Tetrahydro iso-α-acid, hexahydro iso-α-acid or terra hop may be contained within the boiled sugar element, evenly distributed throughout the boiled sugar element, present on the surface of the boiled sugar element or any combination thereof. For instance, the tetrahydro iso-α-acid, hexahydro iso-α-acid or tetra hop may be applied to the surface of the boiled sugar element by incorporation into a hard surface coating or, simply, as a "dusted" coating.

However, preferably, the tetrahydro iso-α-acid, hexahydro iso-α-acid or tetra hop is evenly distributed throughout the boiled sugar element by blending into the primer sugar mixture prior to formation into a solid boiled sugar element. Tetrahydro iso-α-acid, hexahydro iso-α-acid or tetra hop may be incorporated into the primer sugar mixture proir to any manipulation or processing (for example added and/or combined with dry/cystalline sugars), during the application of high heat (at which time the mixture may be less viscous), or worked into the mixture once it has cooled but is still workable and pliable. To avoid the possibility of degradation of head retention agents, the tetrahydro iso-α-acid, hexahydro iso-α-acid or terra hop is preferably added to the priming sugar following the application of high heat to melt the priming sugar, and once the priming sugar has cooled but is still pliable.

The boiled sugar element or sugar drop may be produced by any of the methods well known to persons skilled in the art including a method comprising a step of dissolving appropriate quantities of sugar (the type of sugar is determined by the desired end effect in the secondary fermentation and may comprise glucose, sucrose or other sugar types, in appropriate quantities) in a liquid, generally water. The step of dissolving the sugar may be aided by heat. The resultant mixture is a syrup which is boiled or simmered to concentrate the mixture. The temperature and time for which heat is used, while the mixture is continually stirred, will determine the texture. Once a suitable consistency and texture is achieved it is then appropriate to take the mixture from the heat and kneed/fold the mixture further to remove gases from the mixture. It is during the kneading and folding stage that tetra hop may be readily added, in liquid form, at the desired quantity. Or, if a solid (ie powdered form) of tetra hop is to be used this may be diluted with, for instance, maltodextrin and added to the cooling mixture. The tetra hop is less likely to be reduced in concentration and/or degraded when added at this stage of the production of the sugar drop, or any time thereafter.

Preferably, the boiled sugar element is a hardened, single dosage unit drop. The boiled sugar element is preferably an elongated shape, eg a substantially spheroidal, cylindrical or cuboidal shape, for easy of entry through a bottle neck. Each single dosage unit drop, preferably, comprises about Ig to about 2Og priming sugar, more preferably about 2.5g to about 16.5g priming sugar, even more preferably about 2.5g to about 8.5g, most preferably about 2.5g to about 3.5g priming sugar.

In a second aspect, the present invention provides a beer head retention additive for use at the stage of secondary fermentation of a beer mixture comprising a boiled sugar element comprising terra hop.

Preferably, the quantity of tetra hop present in the boiled sugar element is 0.25% (by weight) but may be within the range 0.05% (by weight) to 2% (by weight). The 0.25% (by weight) amount may be achieved by, for example, adding about 50ml of tetra hop to 19kg of beer mixture.

Preferably, the boiled sugar element is a hardened, single dosage unit drop (eg in a disc-like tablet shape).

In a third aspect, the present invention provides a method for making home brewed beer, said method comprising: pitching a volume of beer wort with a starter culture of yeast; allowing the volume of beer wort to ferment; and adding an amount of tetrahydro iso-α-acid and/or hexahydro iso-α-acid to improve beer head retention; wherein said tetrahydro iso-α-acid and/or hexahydro iso-α-acid is optionally added in combination with an amount of priming sugar for priming a secondary fermentation of said fermented volume of beer wort.

Preferably, the step of adding tetrahydro iso-α-acid and/or hexahydro iso-α-acid comprises adding tetrahydro iso-α-acid, more preferably tetra hop.

Preferably, the steps of pitching a volume of beer wort with a starter culture of yeast and allowing the volume of beer wort to ferment, are conducted in a sealable container, wherein the method of the third aspect may further comprise sealing said container against gaseous and liquid ingress and egress.

Further, the method of the third aspect may, optionally, comprise allowing the fermented volume of beer wort to undergo a secondary fermentation, wherein the secondary fermentation substantially carbonates the fermented volume of beer wort.

In an embodiment of the method of the third aspect, a single sugar drop comprising tetrahydro iso-α-acid, hexahydro iso-α-acid or tetra hop is added to a container, typically a 355-375ml container such as a bottle, before the drawing off of the fermented volume of beer wort (ie the liquid of the primary

fermentation) into said container. If a 740-750ml container is to be filled then two such sugar drops are used. Once the container is filled to within approximately 50mm of the open top, trying to minimise the formation of any foam head, the container can be capped to form a seal to gases and liquids. The seal is of a form and action suitable to prevent the egress of gases from the container as well as sealing against the ingress of gases or moisture into the container, as well of course to provide a liquid seal to prevent egress of the contents. Screw or crown caps can be used.

The sugar drops will dissolve in time but, optionally, the container can be inverted to mix the by-then partly dissolving priming sugar with the liquid contents of the container.

The period of time that elapses to complete secondary fermentation can vary depending on the storage temperature and beer type but generally is about two weeks. The beer will be drinkable at that time, but the time can be extended before consumption, obstensively to improve the taste and other characteristics of the beer.

In a preferred method according to the third aspect, said home brew beer additive preferably comprises tetrahydro iso-α-acid and/or hexahydro iso-α-acid (eg terra hop) in an amount within the range of about 0.0005% (by weight) and about 2% (by weight) and priming sugar in an amount within the range of about 0.5g and 2Og. More preferably, said home brew beer additive comprises tetrahydro iso-α-acid and/or hexahydro iso-α-acid at an amount within the range of about 0.005% (by weight) and about 0.2% (by weight) and priming sugar at an amount within the range of about 2g and 1Og. Most preferably, said home brew beer additive comprises an amount of tetrahydro iso-α-acid and/or hexahydro iso-α-acid of about 0.025% (by weight) and priming sugar of about 4g.

In a fourth aspect, the present invention provides a use of a beer head retention additive in a secondary fermentation of beer in a container comprising: combining a boiled sugar element having a predetermined amount of terra hop with a beer mixture to promote a secondary fermentation phase in the beer mixture.

In a fifth aspect, the present invention provides a kit for making home brewed beer comprising a fermenter for conducting a primary fermentation therein, a home brew wort concentrate, a beer brewing yeast starter culture, and a home brew beer additive comprising tetrahydro iso-α-acid and/or hexahydro iso-α-acid.

The invention is hereinafter described by way of the following non-limiting examples.

EXAMPLES

Example 1 Preparation of high foam carbonation drops

Materials and methods

Preparation of carbonation drops

Carbonation drops were formed according to methods commonly known for making hard boiled sweets.

Carbonation drops were initally formed by mixing 12.95kg cane sugar (approx 70%), liquid 5.55kg glucose (approx 30%) and water, as required to facilitate mixing to homogeneity. The mixture was then brought to the boil in an open pan in which the mixture was concentrated and most of the water was evaporated by maintaining a temperature of about 116 ⁰ C. The mixture was then transferred to a vacuum cooker where the majority of the remaining water was evaporated in a pan capable of holding 18-19kgs.

The hot runny liquid mixture was poured onto a cooling table and worked with metal scrapers to the point of resembling flexible toffee. The mixture was then lifted onto a kneading table and worked for a minute or so to remove any gasses from the mixture.

To shape the mixture into single dosage drops, the worked mixture was then extruded into a rope and fed into a conventional candy moulder holding spinning fingers in the shape of the carbonation drop. The carbonation drops were formed into 3g cuboidal shaped drops, much like barley sugar candies. The drops were air cooled on a conveyer belt, passed through a steam tunnel, and finally tumbled though castor sugar to coat the drops and prevent them sticking to each other.

Preparation of high foam carbonation drops For the preparation of high foam carbonation drops, following the cooling and working of the mixture on the cooling table, terra hop (Botanies, Australia), diluted in a small amount of maltodextin, was added to the mixture which was then lifted onto the kneading table. The terra hop was homogenously incorporated into the mixture during the kneading and working of the mixture. All remaining steps in the preparation of high foam carbonation drops were conducted in the same manner as in the preparation of "regular" carbonation drops.

Results and Discussion

Following the preparation of 3g carbonation drops and 3g high foam carbonation drops as described above, the consistency of high foam carbonation drop product was assessed by preparing 8 trial batches of carbonation drops and high foam carbonation drops. One sample from each batch was used in preparing a home brewed beer (as described below) over a 6 to 8 month period. Consistent head retention in the home brewed beer produced using high foam carbonation drops in comparison with "regular" carbonation drops

showed that high foam carbonation drops produced by the above method produce a consistently dosed terra hop product.

Example 2 Preparation of home brew beer

Materials and methods

Materials

The following equipment and materials were provided for brewing and preparing the home brew beer for consumption.

A plastic fermenter and lid

For brewing the home brew therein. The fermenter (1) (25 litre volume) and Hd (2) was specially designed to ensure an air-tight seal with the lid fitted, as illustrated in Figure Ia.

An adhesive Thermometer strip Affixed midway up the outer wall of the fermenter, a standard thermometer strip (3) (Winequip Pty Ltd,

Coburg, VIC, Australia) was utilised to measure and monitor the temperature of the brew, prior to and during fermentation.

An airlock

An airlock (4) half filled with water as illustrated in Figure Ib, was provided and sealed within an aperture in the fermenter lid by a rubber grommet. The airlock thus fitted within the fermenter lid allows

CO ₂ formed during fermentation to escape whilst preventing any outside contaminants from entering the fermeter during the brewing process.

A plastic tap and sediment reducer

A standard sediment reducer was fitted to the threaded end of the tap (3) which was then screwed into the fermenter (1). The sediment reducer draws liquid from the top of the brew, minimising the amount of yeast sediment transferred when filling beer bottles.

A little bottler

A "little bottler" device, containing a valve which, when fitted to the tap (3), allows bottles to be filled without shutting off the tap. PET bottles

30 x 740ml reusable polyethylene terephthalate (PET) bottles were used and sealed with screw on caps for beer storage.

Carbonation drops

Carbonation drops were prepared as described above in Example 1. Carbonation drops were used to prime the bottles for secondary fermentation at a concentration of one drop per 345ml to 375ml bottle and two drops per 740ml to 750ml bottle.

High foam carbonation drops

High foam carbonation drops were prepared as described above in Example 1. High foam carbonation drops were used to prime the bottles for secondary fermentation at a concentration of one drop per 345ml to 375ml bottle and two drops per 740ml to 750ml bottle and improve head retention. Brewing sugar

Containing dextrose and maltodextrin (Coopers Brewery Limited, Regency Park, SA, Australia). Dried brewers yeast

7g sachet (Coopers Brewery Limited, Regency Park, SA, Australia). Lager concentrate Contains two row barley malt and hops (Coopers Brewery Limited, Regency Park, SA, Australia). A hydrometer

A standard brewers hydrometer was used for measuring the specific gravity of the brew to monitor the progress of fermentation during the brewing process.

Methods

Prior to preparing the brew, all materials were cleaned and sanitised using agents that do not contain detergents or soaps (eg household bleach or agents containing sodium percarbonate may be suitable sanitising agents).

Preparing the wort

The lager concentrate was initially warmed to soften by immersing in a hot water bath (between 6O ⁰ C to 9O ⁰ C) for 10 minutes. The contents of the lager concentrate were poured into the cleaned and sanitised fermenter with any remaining lager concentrate dissolved in boiling water and added to the fermenter. lkg of brewing sugar and 2 litres of boiling water were added to the fermenter and the mixture was stirred until all contents were dissolved. The fermenter was filled to a total volume of 23 litres with water maintained at room temperature, to achieve a mixture at a temperature of between 21 ⁰ C to 27 ⁰ C.

Brewing

Once the wort had reached a temperature of 21 ⁰ C to 27 ⁰ C, 7g dried brewers yeast was added evenly to the surface of the wort and the fermenter was immediately sealed by screwing the fermenter lid on tightly to ensure a secure seal. The airlock and rubber grommet were then fitted in the fermenter Hd and the airlock half filled with cooled boiled water as shown in Figure Ib.

Within several hours, the water within the airlock began to bubble, the visible release of CO ₂ confirming that fermentation had commenced. The water within the airlock continued to bubble, slowing down towards the end of fermentation, within 4-7 days.

To confirm that the fermentation was complete, a small volume of the brew was collected from the fermenter tap to fill the hydrometer tube. The hydrometer was used to measure the specific gravity of the brew sample by floating the hydrometer within the sample. The completion of the fermentation process was confirmed with the specific gravity reading of between 1008 to 1010.

Carbonation

The carbonation of the beer was achieved by conducting a secondary fermentation of the bottled beer under pressure. Prior to bottling the beer, one or two carbonation drops were added to each cleaned and sanitised PET bottle (1 drop for 345-375ml bottles and 2 drops for 740-750ml bottles). The use of carbonation drops ensures that sufficient fermentable sugars are added to adequately carbonate the beer while ensuring the beer is not over carbonated, which can cause bottles to explode.

The effectiveness of the high foam carbonation drops in improving beer head retention was compared with "regular" carbonation drops (ie carbonation drops without tetra hop added) in several beer types. Beer type was varied by altering the starting wort concentrate (all concentrates tested are commercially available from Coopers Brewery Limited, Regency Park, SA, Australia). Table 1 provides a summary of the variables tested.

Table 1 Number of bottles tested from different batches carbonation drops prepared as described in Example 1

Bottles were filled by connecting the little bottler directly to the tap and placing the bottles over the little bottler, such that the base of the bottle releases the little bottler valve and fills the bottle. Bottles were filled to within 50mm from the top of the bottle until the fermenter was almost empty (ie with approximately 25mm of brew containing a thick yeast sediment remaining at the bottom of the fermenter, this remaining sediment was then discarded).

The bottle screw caps were used to seal the bottles, which were then inverted 4 times to mix the priming sugar and beer. Bottles were stored upright at a temperature of between 21°C-27°C for 7 days and thereafter for another 7 days at room temperature.

Results and Discussion

Foam head stability was measured using a Haffmans NIBEM foam stability tester according to the manufacturer's instructions (Haffamans BV, Venlo, The Netherlands). In general, foam stability in home brewed beer is lower than in commercially brewed beer and for most beer types will show foam stability of less than 200. In the following measured, foam stability of greater than 200 was considered to show good foam stability.

As shown in Table 2, the results of foam stability testing in various types of home brewed beer using high foam carbonation drops indicate an improvement in head retention in all beer types with the exception of dark ale home brew, lager home brew, and Bavarian lager home brew. These results were considered promising, although preliminary, as the good majority of beer types showed some improvement.

Notably, the standard deviations in head retention between batches but within beer types, were acceptably low. This indicated good dosing consistency of tetra hop in high foam carbonation drops prepared according to Example 1.

Table 2 Foam stability of various beer types brewed using high foam carbonation drops in comparison with "regular" carbonation drops

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

All publications mentioned in this specification are herein incorporated by reference. Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia or elsewhere before the priority date of each claim of this application.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.