GB2362891A

GB2362891A - Malt beverages

Info

Publication number: GB2362891A
Application number: GB0023503A
Authority: GB
Inventors: Iain Menneer; Stuart William Molzahn; David Edwin Quain
Original assignee: Bass Brewers Ltd
Current assignee: Bass Brewers Ltd
Priority date: 2000-05-31
Filing date: 2000-09-26
Publication date: 2001-12-05
Also published as: GB0023503D0; GB0013052D0

Abstract

Beer in a barrel (1) is dispensed via a supply line (2) to a dispense tap (3). A light source (5) provided between the barrel (1) and the tap (3) illuminates the beer with light having a wavelength of between 350-500 nanometers in order to cause the beer deliberately to become light-struck. That is to say deliberate irradiation of the beer prior to dispense causes the production of 3-methyl-2-butene-1-thiol (MBT) and this improves the post-dispense flavour stability of the beer since it is no longer liable to change flavour if left in the sun.

Description

2362891 1 MALT BEVERAGES This invention relates to malt beverages such as

beer in which the flavour or aroma of the brewed beer is altered when the beer is dispensed for consumption.

More particularly, the invention relates to a method and apparatus for carrying out such modification of the flavour or aroma in a controlled manner.

It is well known that the flavour or aroma of beer is altered by exposure to light, either natural or artificial, producing beer with a distinctive character. This is commonly known in the art as "skunking" and beer exhibiting this character is often referred to as being "lightstruck" although other terms such as "sunstrucC, "sunflavour", lichtgeschmacC "sonnengeschmack", and "gofit de lumiere" are also used.

The skunky flavour or aroma of lightstruck beer is attributed, in the main, to the formation of 3-methyl-2-butene-l-thiol (hereinafter referred to as "MBT"). This compound is very potent, detectable to most humans at levels of a few nanogrammes per litre of beer. MBT is unstable however and the distinctive skunky flavour or aroma it generates is dissipated over a period of time and may not be noticeable after one or two days.

It is believed that exposure to light in the UV region (350 - 500 nanometres) photosensitises riboflavin (vitamin B2) which occurs naturally in beer. Energy from the activated rboflavin is then transferred to hop acids in the beer. A hop acid derived radical molecule is then thought to abstract a sulphydryl radical from one of the many sulphur 2 containing species present in beer to produce MBT giving the beer the distinctive skunky flavour or aroma.

Development of the skunky flavour or aroma starts once the beer is exposed to light but the time for it to become noticeable can vary depending on the conditions under which the beer is exposed to the light. For example, it is found that the time for beer to become lightstruck can range from about one minute in bright sunshine, to a few hours in weak daylight, to a few days under artificial fluorescent lighting.

This can result in the flavour or aroma of the beer changing as it is being consumed. The customer may find this unpleasant causing them to reject the beer and avoid it in the future. This may lead to loss of sales and possibly an unfavourable public perception of the beer which may affect sales of the other brands/types of beers from the same brewer.

Accordingly, development of the skunky flavour or aroma has previously been considered undesirable by the brewing industry and steps have been taken to reduce or prevent the occurrence of lightstruck beer.

Thus, it has been common practice to bottle beer in brown bottles which do not transmit the UV light that causes the beer to become lightstruck. This improves shelf-life of the bottled beer but does not prevent the beer becoming lightstruck once it is dispensed from the bottle into a glass for consumption by the customer. Similarly, beer dispensed from a barrel is protected from becoming lightstruck while in the barrel but is exposed to light when it is dispensed into a glass at a tap for consumption by the customer.

1 3 Using brown glasses could reduce the problem but would almost certainly not be acceptable to the customer who likes to see the colour and clarity of the beer they are consuming.

Hence, the use traditionally of clear glasses, and any change to coloured glasses, would likely be viewed with suspicion by the customer as in some way an attempt to conceal any adverse colour/clarity potentially affecting the quality of the beer.

Accordingly, various attempts have been made to produce beer in which development of the skunky flavour or aroma is prevented even when the beer has been dispensed and is exposed to light.

For example in EP-A-0879878, it is proposed to increase the flavour stability of beer by inactivating the riboflavin-like compounds present in the beer which are believed to be an essential part of the mechanism for producing MBT to give the beer the skunky flavour or aroma.

Another proposal in US-A-4389421 involves the use of an organic compound containing a 1,8-epoxy group and optionally also an organic compound containing a 1,4-epoxy group in place of hops which are also thought to be an essential part of the mechanism for producing MBT to give the beer the skunky flavour or aroma.

Yet another proposal in WO-A-9632465 is to decompose and reduce the riboflavin concentration in the beer by exposure to actinic radiation of specific wavelength during production.

Other proposals to improve the light stability of beers include the use of treated hops to prevent the production of MBT. For example, in US-A- 4 432481 it is suggested to use hop extracts obtained by reducing hops in aqueous solution without use of organic solvents. In US-A-5200227 it is proposed to use modified hop acids, in particular iso-alpha acid solutions containing tetra: hydro iso-alpha acid of hexa:hydro iso-alpha acid with a 5 second iso-alpha acid which dissolves the first.

The foregoing examples illustrate the extent to which the brewing industry has sought to prevent beer being lightstruck and thereby avoid the occurrence of the skunky flavour or aroma associated with beer having 10 this character.

We now believe that rather than being unpleasant or unattractive, some customers actually prefer the skunky flavour or aroma of beer which has become lightstruck and find this character appealing and evocative.

Accordingly, the present invention seeks to provide a malt beverage, in particular beers, in which a skunky flavour or aroma is developed so as to provide beverages having a lightstruck character for consumption by the customer.

The present invention further seeks to provide a method and apparatus for producing lightstruck malt beverages, in particular beers, in which a skunky flavour or aroma is developed in a controlled manner when the beer is dispensed for consumption by the customer.

The present invention also seeks to provide such method and apparatus having application to both draught and bottled beers.

The above objects are achieved broadly by treating the malt beverage such 30 as beer which has been made in the normal manner to modify the original flavour or aroma by exposing the beverage to light having a predetermined wavelength or range of wave-lengths, preferably less than 500 nanometres, for sufficient time to develop a skunky flavour or aroma when the beer is dispensed for consumption by the customer.

In the case of draught beers which are stored in barrels preventing exposure to light and dispensed into glasses for consumption, the beer may be exposed to a suitable artificial light source as it travels from the barrel to the point of dispense so that the beer already has or is developing the skunky flavour as it is being dispensed into the glass. The beer may be exposed to the light source at a position andlor time immediately prior to dispense, or further upstream (in the flowline or time).

Alternatively, the beer may be exposed to a suitable artificial light source on being dispensed into the glass. For example, a font may be provided at the point of dispense to treat the beer in t he glass so as to develop the skunky flavour or aroma.

Both methods provide an opportunity to sell beer which is deliberately lightstruck when it is dispensed to produce the skunky flavour or aroma in a controlled manner.

In this way, the treatment to modify the flavour or aroma of the original beer can be repeated to produce beer having a desired skunky flavour or aroma irrespective of the light conditions to which the beer is subsequently exposed.

As a result, beer can be dispensed in which the flavour or aroma does not 30 alter significantly in the time taken for the beer to be consumed and in 6 which the same flavour or aroma can be obtained within close limits from any dispense point.

In other words, the quality of beer with the skunky flavour or aroma can 5 be maintained with the required certainty through controlled exposure of the beer to an artificial light source by the present invention.

Preferably the light source provides artificial light with a wavelength less than 600 nanometres, more preferably less then 500 nanometres and most preferably in the range 350-450 nanometres. Preferred light sources are gas discharge lamps such as metal halide lamps but other light sources may be used.

Treatment of the beer in-line between the barrel and the point of dispense may be achieved in a number of ways. For example, the line from the barrel to the dispense point, e.g. a tap, may include a transparent or translucent portion and a suitable light source to illuminate the beer with artificial light.

The dimensions of the transparent or translucent portion and/or the rate of flow of the beer and/or the power of the light source may be selected to provide sufficient exposure for the beer to become lightstruck to produce the skunky flavour or aroma when it is dispensed. In this way, the beer may be treated as it is dispensed.

Alternatively, treated beer may be contained in a holding reservoir provided in the line from the barrel to the dispense point. In this way, a sufficient volume of treated beer may be javailable for dispense on demand. The beer may be exposed to a suitable light source as abovedescribed in the reservoir itself. For example, the reservoir may be of 1 7 transparent or translucent material. Alternatively, the beer may be treated upstream of the reservoir by exposure to a suitable light source and passed to the reservoir as beer is being dispensed. With this arrangement we may choose to re-circulate a portion of the beer in the reservoir for further exposure to the light source. Re-circulated beer may be mixed with new untreated beer and returned to the reservoir where mixing occurs to eliminate any noticeable variation in the lightstuck character of the beer when it is disposed.

Treatment of the beer at the point of dispense may be effected by providing a font or chamber in which the glass is positioned with a light source arranged to illuminate the glass either during or immediately after the beer has been dispensed into the glass, or both.

This method of treating the beer when it is dispensed in the glass may be used to promote the change in flavour or aroma produced by the beer being deliberately lightstruck in a way which customers may find entertaining and lead to increased sales of the treated beer.

This method of treating the beer also lends itself to the treatment of bottled beers which have been stored in brown bottles to inhibit the lightstruck character until the beer is purchased and poured into a glass for consumption.

In this way, the customer can choose between bottled beer having the original flavour or aroma of the brewed beer or the modified skunky flavour or aroma.

1 According to another aspect of the invention, there is provided a method of treating a malted beverage such as beer to modify the original flavour 8 or aroma of the beverage as brewed by exposing the beverage to a light source when the beverage is dispensed for consumption.

According to yet another aspect of the present invention, there is provided apparatus for producing a lightstruck malted beverage such as beer comprising a light source adopted for illuminating the beverage when the beer is dispensed for consumption.

According to yet another aspect of the present invention, there is provided a malted beverage such as beer which has been deliberately lightstruck to modify the original flavour or aroma of the beverage when the beverage is dispensed for consumption.

The benefits and advantages of the invention in each of its aspects will be more readily understood from the following description of exemplary embodiments with reference to the accompanying drawings in which like reference numerals are used throughout to indicate corresponding parts and wherein-

Figure 1 shows diagrammatically apparatus for in-line treatment of beer to modify the flavour or aroma according to the present invention; Figures 2 to 7 show diagrammatically alternative arrangements for in-line treatment of beer to modify the flavour or aroma according to the present invention; Figure 8 shows diagrammatically an arrangement for dispensing treated or untreated beer from a common source; 9 Figure 9 shows diagrammatically apparatus for point of dispense treatment of beer to modify the flavour or aroma according to the present invention; Figure 10 shows diagrammatically an alternative arrangement for point of dispense treatment of beer to modify the flavour or aroma according to the present invention; Figure 11 shows diagrammatically an alternative arrangement for dispensing treated or untreated beer from a common source; Figure 12 shows diagrammatically another apparatus for treatment of dispensed beer to modify the flavour or aroma according to the present invention; Figure 13 is a table showing the results of tests to determine the effects of varying the volume and exposure time of treated beer on the development of the desired skunky flavour or aroma in the treated beer:

Figure 14 is a schematic plan view of an apparatus for treating beer inline between the barrel and point of dispense to develop the desired skunky flavour or aroma in the treated beer; and Figure 15 is a schematic end view of the apparatus shown in Figure 14.

In the following description of exemplary embodiments various arrangements for treating beer to develop the desired skunky flavour or aroma in the treated beer will first be described with reference to Figures 1 to 12 followed by an explanation of tests we have carried out to determine the effect of volume and exposure time on the development of the skunky flavour or aroma with reference to Figure 13 and one apparatus we have developed for optimising the treatment of beer to produce the skunky flavour or aroma with reference to Figures 14 and 15.

In the United Kingdom, two methods are commonly employed for automated dispense of beer from a tap connected to a barrel by a supply line. In one method, the tap is arranged to dispense the beer in predetermined metered volumes, typically half-pint measures on demand (so called "metered dispense"). In the other method, the tap is arranged to dispense the beer continuously on demand with the volume dispensed being controlled by opening and closing the tap (so called "free flow dispense"). Whichever method of dispense is employed (metered or freeflow), the time to dispense a full pint is generally similar and typically in the range of 20-30 seconds.

The exemplary embodiments described hereinafter are provided to show how we may be able to produce a conversion rate for obtaining treated beer with the desired skunky flavour or aroma within the existing dispense times to enable the invention to be employed without changing the equipment currently being used to dispense beer. In particular, the invention is intended to provide a method and apparatus for treating beer which can either be incorporated in the flow-line between the barrel and dispense point so that the beer has the skunky flavour or aroma when it is dispensed or be provided at the dispense point so that the skunky flavour or aroma is produced in the glass at the time the beer is dispensed. In other words, by this invention we aim to be able to adapt existing dispense systems to provide beer having a skunky flavour or aroma with minimum disruption to the system. As a result, installation costs should be kept to a minimum and the apparatus for producing the skunky flavour or aroma in the beer can be easily fitted and maintained.

1 11 Referring now to Figure 1 of the drawings, a barrel 1 containing a malted beverage (not shown) such as beer is shown connected by line 2 to a dispense tap 3 for dispensing beer for consumption. As mentioned previously the tap 3 may be arranged to provide metered or free flow dispense of the beer in known manner.

The barrel 1 is made of metal, e.g. aluminium and is sealed after filling with beer for delivery to an outlet such as an inn, restaurant or hotel. In this way the beer is protected from becoming lightstruck during transit, storage in the barrel 1 and the flavour or aroma of the beer as brewed is maintained prior to dispensing.

The line 2 includes a window or section of transparent or translucent material e.g. glass or food grade plastics, in the region AB connected to the tap 3. The remainder of the line 2 may be made of metal or food grade plastics. Alternatively, the whole of the line 2 may be made of transparent or translucent material.

The section 4 is provided with a light source 5 for illuminating the beer in the section AB. The light source 5 may comprise a hollow tubular lamp through which the line 2 extends so as to be completely surrounded by the light source 4. Alternatively, the light source may comprise one or more lamps circumferentially spaced apart around the line 2. Suitable light sources include an incandescent light source or a gas discharge light source which emit light having a wavelength in the region 200 to 600 nanometres and more preferably in the region 350 to 500 nanometres. It will be understood, however, that any suitpble light source may be employed.

12 In use, when tap 3 is opened, beer is dispensed into a glass, and at the same time, light source 5 is energised to illuminate the beer in section 4 of the line 2. As the beer is dispensed, it is exposed to light having a wavelength or range of wavelengths which cause the beer to become 5 lightstruck thereby modifying the original flavour or aroma to produce a skunky flavour or aroma characteristic of lightstruck beer.

As described in more detail later the dimensions of section 4, and the intensity of the lightstruck wavelength(s) of the light source 5 are chosen so that the beer dispensed from the tap 3 has developed the required skunky flavour or aroma more or less completely with the existing flow rates to maintain a dispense time of 20-30 seconds for a pint of beer.

As will be appreciated, beer which remains in section 4 when the tap 3 is closed and light source 5 de-energised will have been exposed for varying amounts of time to the light source 5 so as to begin the development of the skunky flavour or aroma. This, together with the further exposure that occurs when the tap 3 is next opened is sufficient to produce the required skunky flavour or aroma.

Generally, it is envisaged that normal rates of consumption of the beer will be such that the dwell or standing time of beer in section 4 between the dispensing of successive volumes of beer will be such that the skunky flavour or aroma produced will be substantially unaffected. Thus, although, the MBT responsible for the skunky flavour or aroma is unstable as previously explained, the rate of which the MBT breaks down is sufficiently slow to avoid noticeable changes to the skunky flavour or aroma of any treated beer remaining in thp section 4 under normal consumption rates.

1 13 Furthermore, once developed, the skunky flavour or aroma is sufficiently stable that the customer should not notice any further change in flavour or aroma of the dispensed beer while it is being consumed.

The volume of beer in the section 4 may be more than, less than or equal to the volume of beer dispensed when the tap 3 is opened provided the beer is exposed to the light source 5 for sufficient time within the section 4 to develop the skunky flavour or aroma.

Alternatively or additionally more than one section 4 and light source 5 may be provided along the length of the line 2 providing sequential treatment of the beer as it passes through each section 4 for dispense from tap 3 in order to produce the desired skunky flavour or aroma when the beer is dispensed.

Where more than one section 4 is provided, each section 4 and light source 5 may be the same or different so as to control development of the skunky flavour or aroma of the beer dispensed from tap 3.

Referring now to Figures 2 to 7, six alternative arrangements are shown for treating beer in the line 2 from the barrel 1 to the dispense tap 3.

Figure 2 shows a holding reservoir 6 provided in the line 2. The reservoir 6 is made of transparent or translucent material similar to section 4 and is surrounded by a light source 5.comprising a single lamp or an array of lamps as described previously.

The reservoir 6 contains more than the volume,of beer normally dispensed at one time, e.g. 1/2 pint or pint, thereby ensuring a sufficient volume of 30 beer treated to produce a skunky flavour or aroma is available for 1 14 dispensing successive volumes of beer having the same quality of flavour or aroma on demand with existing dispense times of 20-30 seconds for a pint.

The reservoir 6 has the same effect as treating smaller volumes of beer in successive sections of the line 2 and has the advantage of being simpler to provide. It will be understood, however, that more than one reservoir 6 and light source 5 may be provided in line 2 if desired.

Figure 3 shows a modification of the arrangement of Figure 2 in which the beer is exposed to the light source 5 in section 4 of the flow-line 2 upstream of the reservoir 6.

This may be preferable to treating the beer in the reservoir 6 in order to 15 produce the skunky flavour or aroma at a rate which enables existing dispense times to be maintained.

In this respect, it may be beneficial to include a re-circulation line 2a whereby some of the beer in the reservoir 6 is re-circulated through section 4 and re-exposed to the light source 5 for developing the skunky flavour or aroma.

Such re-circulation may be carried out only when beer is being dispensed so that untreated beer from the barrel 1 is mixed with treated beer from the reservoir 6. In this way, the volume of untreated beer in which a skunky flavour or aroma is developed is reduced for each volume of beer dispensed from the tap 3 and the provision of the reservoir 6 ensures the beer from the section 4 is mixed with previoulply treated beer so that the beer dispensed from the tap 3 has a substantially uniform skunky flavour or aroma.

Alternatively, re-circulation may be carried our independently of dispense from tap 3. In this way, the skunky flavour or aroma may be developed in the beer stored in the reservoir 6 when the tap 3 is closed. This may enable small volumes of beer to be treated in section 4 reducing the size and cost of the apparatus required for the treatment to be carried out in an effective, economical manner without changing the existing dispense times.

Figure 4 shows another modification in which the reservoir 6 is cylindrical with an inlet 6a and an outlet 6b at opposite ends for connecting in the flow-line (not shown) and the light source 5 is arranged axially at the centre of the reservoir 6. In this way, the light source 5 may provide a more efficient illumination of the beer in the reservoir 6 than one or more light sources 5 spaced around the outside of the reservoir 6.

Figure 5 shows, the light source 5 arranged to illuminate a section 11 of the dispense line 2 having a sinusoidal, serpentine coil, or other convoluted shape.

The section 11 increases the volume of beer which can be treated by a given size of light source 5. In this way, it may be possible to treat a half-pint or full pint measure by a single illumination without requiring an excessively long light source. In other words, the section 11 provides a compact treatment zone for producing lightstruck beer in sufficient quantities for dispense in the usual measures.

16 Figure 6 shows, the light source 5 arranged on one side of the dispense line 2 and a concave mirror 12 or similar reflecting surface provided to partially enclose the line 2.

The mirror 12 collects and reflects light from the light source 5 to provide illumination around the whole circumference of the line 2. In this way, the light source 5 does not have to surround the line 2 allowing light sources 5 of simpler construction to be used. The mirror 12 may be used with straight section of the line 2 or with a reservoir 6 as shown in Figures 2 to 4 or with a convoluted section 11 as shown in Figure 5.

Figure 7 shows an arrangement in which beer in the supply line 2 is cooled by water circulated in line 15 arranged alongside the supply line 2 between the barrel 1 and tap 3, and the light source 5 for illuminating the beer is positioned alongside the line 15 and the supply line 2. The light source 5 may extend between the barrel 1 and the tap 3. With this arrangement, the lines 2, 15 and the light source 5 may be provided as an integrated unit with suitable end connectors.

Alternatively, the lines 2, 15 may be provided as an integrated unit with the light source 5 positioned at an appropriate location between the barrel 1 and tap 3. As will be appreciated, considerable heat can be generated by the light source 5 and water cooling ensures the beer is delivered to the tap 3 at the desired temperature for dispense.

With reference now to Figure 8, there is shown an arrangement in which barrel 1 is connected to three dispense taps 3a, 3b, 3c of which one tap 3b is adapted to dispense beer having the skunky. flavour or aroma, and the other two taps 3a, 3c are arranged to dispense beer having the original flavour and aroma.

17 In this way, two beers having different flavours or aromas can be dispensed at separate dispense taps 3a, 3b, 3c from a single supply barrel 1. The taps may be branded differently, giving the consumer the 5 impression that they dispense different beers (which they do).

As a result, the rate of consumption of beer from barrel 1 is increased, reducing the risk of beer going stale in the barrel and improving choice for the customer without having to provide separate supplies of the different beers.

It will be appreciated this has advantages for the brewer, retailer and customer. Thus the brewer can supply one beer which the retailer can sell with or without modification of the original flavour or aroma and ensuring greater freshness for the customer by reducing the time to empty the barrel 1.

It will be understood that the number of dispense taps 3a, 3b, 3c connected to the barrel 1 may be altered as desired and that the number of taps 3a, 3b, 3c for dispensing modified and unmodified beer may be chosen as required to meet demand. For example, each tap 3a, 3b, 3c may be provided with one or more treatment sections 4 and light sources 5 with a switch (not shown) which the bar staff can operate to change the tap 3a, 3b, 3c to dispense modified or unmodified beer as desired.

Referring now to Figure 9, this shows an alternative apparatus for modifying the flavour or aroma of beer dispensed from tap 3. In this embodiment, light source 5 is provided to illuTinate a glass 9 into which beer 8 is dispensed from tap 3 while standing on a support 7.

18 The light source 5 may be operated in response to activation of the tap 3 or it may be operated separately by the bar staff when dispensing the beer.

Where the light source 5 is operated separately, this may be done while the beer is being dispensed andlor immediately afterwards so as to expose the beer for a sufficient pre-determined length of time to develop the skunky flavour or aroma.

This method of treating the beer to modify the flavour or aroma can be seen by the customer and this may be used to provide visual entertainment to promote treatment of the beer when it is dispensed. Alternatively, or additionally, some form of audible signal of the treatment may be provided, for example a musical jingle, to add to the entertainment value of the treatment.

Figure 10 shows an alternative arrangement of light source 5 for illuminating beer dispensed into a glass 9 in which the light source 5 is positioned on one side and the glass 9 is partially enveloped by a concave mirror 12 or similar reflecting surface. The mirror 12 collects and reflects light from the light source onto the glass 9 to treat the beer inthe glass 9 enabling a light source 5 of simple construction to be used similar to Figure 6.

Referring now to Figure 11, there is shown an alternative arrangement, similar to Figure 8, in which the barrel is connected to several taps 3a, 3b, 3c for dispensing modified or unmodified beer as required.

Turning to Figure 12, a further apparatus for modifying the flavour or 30 aroma of beer dispensed from tap 3 is shown. In this embodiment the 19 light source 5 is provided in a separate chamber or font 10 positioned adjacent to the tap 3 in which the glass 9 containing the beer 8 is placed after the beer has been dispensed. The beer 8 can then be exposed to the light to modify the flavour or aroma. The font 10 may include a mirror or similar reflecting surface to enhance the illumination of the beer by the light source 5.

This may be done by the bar staff or the font 10 may be arranged to allow the customer to carry out the treatment themselves. This may add further to the entertainment value of the treatment and may be accompanied by visual and/or audible effects to enhance the entertainment value.

The apparatus and arrangements for treating the beer when dispensed into a glass as shown in Figures 9 to 12 may also be used to treat bottled beers which have been dispensed into a glass for consumption. Alternatively, the bottled beers may be treated prior to dispense into a glass by exposure to an appropriate light source.

With reference now to Figure 13, there is shown a table containing the results of tests carried out on a lager beer (Carling - ex Bass Brewers in the UK) to provide a qualitative comparison by smell and taste of the effects of varying the volume of beer treated and the exposure time. In each test, the area of a static sample exposed to the light source was the same. In this way, changing the volume effectively altered the depth (or thickness) of the sample being illuminated to provide an indication of the effect of absorbance of the light by the beer on the development of the skunky flavour or aroma. For these tests a 400 watt metal halide discharge lamp mounted in a reflector housing.and an output in the range 350-450 mm was used to illuminate the samples.

As can be seen from the table, the strength of the skunky flavour or aroma detected by taste and smell of the samples increases for each volume with longer exposure times and reduces for each exposure time with larger volumes.

From these results it can be seen that a discernible skunky flavour or aroma can be achieved with an exposure time of 15-30 seconds compatible with dispense times for one pint of beer using existing metered or free flow dispense.

Using this information we have developed apparatus to produce lightstruck beer which may be incorporated in the supply line from the barrel to the tap. This apparatus shown schematically in Figures 14 and 15 is contained in a rectangular housing 20 having a hinged lid 21 for access which can be locked in the closed position to prevent unauthorised access to the apparatus.

The apparatus includes a light source 5 positioned below a rectangular, transparent flow cell 22 having a thickness of 20mm with an inlet 22a at one end and an outlet 22b at the other end for connection in a supply line between a barrel and a dispense tap (not shown). The light source 5 is a 400 watt metal halide discharge lamp with an output in the range 350 to 450mm. A driver 23 for the lamp is connected to the mains electricity supply and the lamp is intended to be operated continuously to avoid delays from switching the lamp on and off. A shutter 24 is provided for controlling exposure of beer in the cell 22 to the light source 5 and a fan 25 is provided to circulate air through the housing to cool the lamp and prevent the beer being heated during treatment to develop the skunky flavour or aroma.

21 The apparatus is designed so that the shutter 24 normally blocks the light source 5 until the dispense tap 3 is opened to provide metered or free flow dispense of the required volume of beer 0/2 pint or pint). On opening the tap 3, the shutter 24 is displaced by sliding or pivotal movement to expose the beer in the cell 22 to the light source. The volume of the cell 22 is selected together with the thickness and the flow rate of the beer to ensure the desired lightstruck character is developed as the beer flows through the cell 22.

Depending where the apparatus is sited in the flow line, the treated beer may pass directly to the tap for dispense to the glass. More usually, however, the apparatus will be sited away form the tap, for example in the cellar, to facilitate installation and maintenance, as well as restricting access to the apparatus for safety and security. In this case, treated beer will flow from the apparatus to the supply line and, depending on the volume of beer contained in the supply line, will be dispensed at some time in the future. In other words, there will be a delay between treatment and dispense of the beer. However, once developed, the skunky flavour or aroma is stable for several hours to prevent any noticeable change in the lightstruck character between exposure to the light source 5 and dispense from the tap under normal circumstances.

The apparatus includes an automatic cut-out to isolate the power supply and switch-off the lamp when the lid 21 is opened. In this way, risk of exposure to the light source 5 if the lid 21 is opened without switchingoff the lamp is avoided.

It is also envisaged that the lamp will be provided in the form of a replaceable cartridge which can be removed and replaced to fit a new lamp when required without opening the lid 21. For example, the 22 cartridge may be a push-fit with a lock or other device to prevent accidental or unauthorised removal.

Although the invention has been described with reference to various embodiments, it will be understood these are given by way of non-limiting example only and that the invention is deemed to include all variations and combinations of the features described to produce the desired lightstruck character.

Other modifications or improvements will be apparent to those skilled in the art and are deemed within the scope of the invention. For example, the treatment to modify the flavour or aroma of the beer by exposure to a light source may heat the beer requiring additional cooling to provide beer at the required temperature for consumption by the customer. Depending on the location of the light source, the additional cooling may be provided by any suitable means. For example, in-line treatment may allow cooling to be effected prior to dispensing the treated beer from the tap 3. Alternatively, or where the beer is treated after dispensing from the tap 3, the cooling may be carried out with a cooling unit. The cooling unit may be separate from or incorporated in the unit for treating the beer so that it is cooled after the flavour or aroma has been modified. Such cooling may allow the skunking flavour or aroma to develop completely before the customer receives the beer.

It will be appreciated that the term "beer" is intended to include beer proper, lager, ale, porter, stout, and no alcohol and low alcohol versions of such malted beers.

Finally, we may also be able to alter or adjust the lightstruck character of 30 malt beverages according to this invention by the use of ultrasonics to 23 provide radical formation as part of the process to produce MBT, and/or by modifying the recipe for the beverage, for example to increase the amount of riboflavin or change the hop material.

24

Claims

A method of providing a beverage comprising treating a malted beverage such as beer to modify the original flavour or aroma of the beverage as brewed by exposing the beverage to a light source when the beverage is dispensed for consumption.
2. A method according to claim 1 in which a malt beverage such as beer made in the normal manner is treated to modify the original flavour or aroma by exposing the beverage to light having a pre-determined wave length.
3. A method according to claim 1 or claim 2 in which draught beer stored in barrels is exposed to an artificial light source as it travels from the barrel to the point of dispense so that the beer has a skunky flavour as it is dispensed.
4. A method according to any preceding claim in which the beer is exposed to the light source at a position and/or time immediately prior to dispense.
5. A method according to any preceding claim in which the beer is exposed to an artificial light source on being dispensed into the glass.
6. A method according to claim 5 in which a font is provided at the point of dispense to treat the beer in the glass so as to develop the skunky flavour or aroma.
7. A method according to any preceding claim in which the light source has a predetermined wavelength or range of wavelengths less than 500 nanometres.
8. A method according to any preceding claim in which the beverage is exposed to the light source for a period of time to develop a skunky flavour.
9. A method according to any preceding claim in which treated beer is contained in a holding reservoir provided in a dispense line from the barrel to the dispense point.
10. A method according to claim 9 in. which the beer is treated upstream of the reservoir by exposure to the light source and is passed to the reservoir.
11. A method according to claim 5 or 6 in which bottled beers are poured into a glass and treated by exposure to the light source.
12. A method according to any preceding claim wherein the method is substantially as described with reference to the accompanying drawings.
13. An apparatus for producing a lightstruck malted beverage such as beer comprising a light source adapted for illuminating the beverage when the beer is dispensed for consumption.
14. An apparatus according to claim 13 in which a dispense line is provided adapted to transport beverage, and includes a window or section of transparent or translucent material to enable the light striking process to occur.

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15. An apparatus according to claim 13 or claim 14 in which an incandescent light source or a gas discharge light source is provided, and which the light source emits light having a wavelength in the region 2005 600 nanometres.
16. An apparatus according to claim 15 wherein the light source emits light at a wavelength in the region of 350-500 nanometres.
17. An apparatus according to any one of claims 13 to 16 in which a holding reservoir is provided in a beer dispense line, the holding reservoir having transparent or translucent material and there being a single lamp or plurality of lamps adjacent or surrounding the holding reservoir.
18. An apparatus according to any one of claims 13 to 17 in which beer is exposed to a light source before being sent to a holding reservoir to enable the flavour and aroma to be dispensed at a rate allowing dispense times to be maintained.
19. An apparatus according to any one of claims 13 to 18 in which at least some of the beer from the holding reservoir can be redirected back past the light source to develop the skunky flavour and aroma.
20. An apparatus according to any one of claims 13 to 19 in which a cylindrical reservoir is attached to an inlet and an outlet, and a light source is arranged axially at the centre of the reservoir.
21. An apparatus according to any one of cl.aims 13 to 20 in which the dispense line contains a section of sinusoidal, serpentine coil or any other 30 convoluted shape, illuminated by a light source.

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22. An apparatus according to any one of claims 13 to 21 in which a light source is arranged on one side of a dispense line opposite a concave mirror or similar reflecting surface provided at least partially to enclose the line, and the light emitted from the light source can be reflected around, substantially, the whole circumference of the dispensing line.
23. An apparatus according to any one of claims 13 to 22 in which the beer in the supply line is cooled by water in a line arranged near the supply line and the light source is arranged next to the supply line.
24. An apparatus according to any one of claims 13 to 23 in which the light source extends from a barrel to a dispense tap via end connectors.
25. An apparatus according to claims 13 and 24 in which the light source and water line are positioned between the barrel and tap.
26. An apparatus according to any one of claims 13 to 25 in which there are two or more dispense taps, and one of the taps is adapted to dispense beer having the skunky flavour or aroma and another of the taps is so arranged to dispense beer having the original flavour and aroma.
27. An apparatus according to any one of claims 13 to 26 in which a light source is provided to illuminate a glass into which beer is dispensed in use from a tap.
28. An apparatus according to claim 27 wherein a glass of beer dispensed from a tap is adapted to be illuminated by a light source which has its light, in use, reflected around the circumference of the glass of beer by a concave mirror or similar reflecting surface.

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29. An apparatus according to any one of claims 13 to 28 in which a barrel is connected to at least three beer taps for dispensing beer that can be modified or unmodified as required.
30. An apparatus according to any one of claims 13 to 29 in which a light source is provided in a separate chamber or font positioned adjacent to a tap, the chamber or font being adjusted to receive in use a glass of beer and to expose the glass of beer to a light source.
31. An apparatus according to claim 30 in which the chamber or font also houses, as well as a light source, a mirror or similar reflective surface.
32. An apparatus according to any one of claims 13 to 31 in which the apparatus includes a light source positioned adjacent a transparent flow cell with an inlet at one end and an outlet at the other end for connection in a supply line between a barrel and a dispense tap; the light source being, for example, a metal halide discharge lamp and having an output in 20 the range 350 to 450 nm; and a driver for the light source connected to the mains electricity supply.
33. Apparatus according to any one of claims 13 to 32 in which the light source is adapted to be operated continuously.
34. Apparatus according to any one of claims 13 to 33 in which a shutter is provided for controlling the exposure of beer in the cell to the light source.

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35. Apparatus according to any one of claims 13 to 34 in which a fan is provided to circulate air in use to cool the light source and thereby prevent the beer being heated significantly during light treatment to develop the skunky flavour or aroma.
36. An apparatus according to any preceding claim wherein the apparatus is substantially as described with reference to the accompanying drawings.
37. A malted beverage which has been deliberately lightstruck to modify the original flavour or aroma of the beverage when the beverage is dispensed for consumption.
38. A malted drink according to any preceding claim which has been produced according to the method of any one of claims 1 to 12; or which has been dispensed using the apparatus of any one of claims 13 to 36.

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