Light-stable hop extract

Abstract

The invention relates to a light-stable hop extract comprising at least 1 g per kg of dry matter of one or more hop derived substances represented by formula (I), wherein RCH(CH.sub.3).sub.2, CH(CH.sub.3)CH.sub.2CH.sub.3 or CH.sub.2CH(CH.sub.3).sub.2. The invention further relates to the use of the light-stable hop extract in beer and to a method of preparing such a hop extract. ##STR00001##

Claims

1. A beer comprising light-stable hop extract, the beer comprising at least 40 g/l riboflavin and at least 0.1 mg/l of one or more hop derived substances represented by formula (I): ##STR00007## wherein RCH(CH.sub.3).sub.2, CH(CH.sub.3)CH.sub.2CH.sub.3 or CH.sub.2CH(CH.sub.3).sub.2.

2. The beer according to claim 1, wherein the beer comprises at least 0.2 mg/l of the one or more hop derived substances.

3. The beer according to claim 2, wherein the beer comprises at least 0.4 mg/l of the one or more hop derived substances.

4. The beer according to claim 3, wherein the beer comprises at least 1 mg/l of the one or more hop derived substances.

5. The beer according to claim 1, wherein the beer comprises not more than 50 mg/l of the one or more hop derived substances.

6. The beer according to claim 1, wherein the beer comprises at least 60 g/l of riboflavin.

7. The beer according to claim 1, wherein the one or more hop derived substances and riboflavin are present in a weight ratio that does not exceed 200:1.

8. The beer according to claim 7, wherein the one or more hop derived substances and riboflavin are present in a weight ratio that is in the range of 1:1 to 100:1.

9. The beer according to claim 1, wherein the beer comprises at least 0.1 mg/l of iso-alpha acids.

10. The beer according to claim 9, wherein the beer comprises at least 0.3 mg/l of iso-alpha acids.

11. The beer according to claim 10, wherein the beer comprises at least 0.6 mg/l of iso-alpha acids.

12. The beer according to claim 9, wherein the beer comprises at least 1% by weight of the iso-alpha acids of the hop derived substances.

13. The beer according to claim 12, wherein the beer comprises at least 3% by weight of the iso-alpha acids of the hop derived substances.

14. The beer according to claim 13, wherein the beer comprises at least 5% by weight of the iso-alpha acids of the hop derived substances.

15. A light-stable hop extract comprising at least 1 g per kg of dry matter of one or more hop derived substances represented by the following formula (I): ##STR00008## wherein RCH(CH.sub.3).sub.2, CH(CH.sub.3)CH.sub.2CH.sub.3 or CH.sub.2CH(CH.sub.3).sub.2.

16. The hop extract according to claim 15, wherein the hop extract comprises the one or more hop derived substances in a concentration of at least 3 g per kg of dry matter.

17. The hop extract according to claim 16, wherein the hop extract comprises the one or more hop derived substances in a concentration of at least 6 g per kg of dry matter.

18. The hop extract according to claim 17, wherein the hop extract comprises the one or more hop derived substances in a concentration of at least 10 g per kg of dry matter.

19. The hop extract according to claim 15, wherein the hop extract comprises at least 1% by weight of the iso-alpha acids of the one or more hop derived substances.

20. The hop extract according to claim 19, wherein the hop extract comprises at least 3% by weight of the iso-alpha acids of the one or more hop derived substances.

21. The hop extract according to claim 15, wherein the hop extract comprises at least 1% of iso-alpha acids by weight of dry matter.

22. The hop extract according to claim 15, wherein the hop extract comprises alpha-acids in a concentration of 0-10% by weight of dry matter.

23. The hop extract according to claim 15, wherein the hop extract comprises beta-acids in a concentration of 0-10% by weight of dry matter.

24. The hop extract according to claim 15, wherein the hop extract comprises reduced iso-alpha acids in a concentration that does not exceed 10% by weight of the iso-alpha acids; the reduced iso-alpha acids being selected from the group consisting of dihydro-iso-alpha acids, tetrahydro-iso-alpha acids, hexahydro-iso-alpha acids and combinations thereof.

25. A process of preparing a beer, comprising introducing a hop extract according to claim 15 to the beer.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows the mass spectrum of the hop derived substance Co1.

(2) FIG. 2 shows the mass spectrum of the hop derived substance Co2.

(3) FIG. 3 shows the mass spectrum of the hop derived substance N1.

(4) FIG. 4 shows the mass spectrum of the hop derived substance N2.

DETAILED DESCRIPTION OF THE INVENTION

(5) Accordingly, a first aspect of the present invention relates to a light-stable hop extract comprising at least 1 g per kg of dry matter of one or more hop derived substances represented by the following formula (I):

(6) ##STR00005##
wherein RCH(CH.sub.3).sub.2, CH(CH.sub.3)CH.sub.2CH.sub.3 or CH.sub.2CH(CH.sub.3).sub.2.

(7) The term hop derived substances as used herein, unless indicated otherwise, refers to substituted oxycyclohexyl substances represented by aforementioned formula (I). The aforementioned hop derived substances can occur in different isomeric forms. All these isomeric forms, including tautomers and stereo-isomeric forms are encompassed by the above mentioned definition hop derived substances.

(8) The term iso-alpha acids as used herein refers to substances selected from the group of isohumulone, isoadhumulone, isocohumulone, pre-isohumulone, post-isohumulone and combinations thereof. The term iso-alpha acids encompasses different stereo-isomers (cis-iso-alpha acids and trans-iso-alpha acids).

(9) The term alpha acids as used herein refers to substances selected from the group ofhumulone, adhumulone, cohumulone, prehumulone, posthumulone and combinations thereof.

(10) The term beta acids as used herein refers to substances selected from the group of lupulone, adlupulone, colupulone, prelupulone, and postlupulone and combinations thereof.

(11) The term isohumulone derived substance as used herein refers to hop derived substances as defined above, wherein RCH.sub.2CH(CH.sub.3).sub.2.

(12) The term isocohumulone derived substance as used herein refers to hop derived substances as defined above, wherein RCH(CH.sub.3).sub.2.

(13) The term beer as used herein encompasses both alcohol-containing and alcohol-free beer.

(14) The concentration of the hop derived substances in a hop extract or in beer can suitably be determined by means of LC-MS, using the methodology that is described in this document.

(15) The light-stable hop extract of the present invention typically contains the hop derived substances in a concentration of at least 3 g per kg of dry matter, more preferably in a concentration of at least 6 g per kg of dry matter and most preferably of at least 10 g per kg of dry matter. Typically, the hop extract contains not more than 350 g, preferably not more than 250 g of the hop derived substances per kg of dry matter.

(16) According to a preferred embodiment of the present invention, the light-stable hop extract contains significant amounts of one or more hop derived substances according to formula (I) in which RCH(CH.sub.3).sub.2. This hop derived substance is believed to originate from isocohumulone and is referred to herein as isocohumulone derived substance. Typically, the light-stable hop extract contains the isocohumulone derived substance in a concentration of at least 0.3 g per kg of dry matter, more preferably in a concentration of at least 1 g per kg of dry matter and most preferably of at least 3 g per kg of dry matter.

(17) As explained below, the inventors have identified two isocohumulone derived substances in the light-stable hop extract of the present invention. These two isocohumulone derived substances, referred to as Co1 and Co2, are described in more detail below. Typically, the light-stable hop extract contains the isocohumulone derived substance Co2 in a concentration of at least 0.2 g per kg of dry matter, more preferably in a concentration of at least 0.7 g per kg of dry matter and most preferably of at least 2 g per kg of dry matter.

(18) According to a further preferred embodiment of the present invention, the light-stable hop extract contains significant amounts of one or more hop derived substances according to formula (I) in which RCH.sub.2CH(CH.sub.3).sub.2. This hop derived substance is believed to originate from isohumulone and is referred to herein as isohumulone derived substance. Typically, the light-stable hop extract contains the isohumulone derived substance in a concentration at least 0.5 g per kg of dry matter, more preferably in a concentration of at least 2 g per kg of dry matter and most preferably of at least 5 g per kg of dry matter.

(19) The light-stable hop extract of the present invention typically contains at least 1%, more preferably at least 2% and most preferably at least 3% of iso-alpha acids by weight of dry matter.

(20) According to a particularly preferred embodiment of the present invention the light-stable hop extract contains the hop derived substances in a concentration of at least 1%, more preferably at least 3%, even more preferably at least 5%, yet more preferably at least 10% and most preferably at least 20% by weight of the iso-alpha acids that are contained in the extract.

(21) Typically, the light-stable hop extract contains at least 0.3%, more preferably at least 3% and most preferably at least 6% of the isocohumulone derived substance by weight of the iso-alpha acids that are contained in the extract.

(22) The light-stable hop extract preferably contains at least 0.5%, more preferably at least 5% and most preferably at least 10% of the isohumulone derived substance by weight of the iso-alpha acids that are contained in the extract.

(23) Alpha acids are typically contained in the light-stable hop extract in a concentration of 0-10%, more preferably of 0-3% and most preferably of 0.01-2% by weight of dry matter.

(24) The light-stable hop extract of the present invention typically contains 0-10% beta acids by weight of dry matter, more preferably 0-5% beta acids by weight of dry matter.

(25) The amount of reduced iso-alpha acids (dihydro-iso-alpha acids, tetrahydro-iso-alpha acids and hexahydro-iso-alpha acids) in the light-stable hop extract preferably does not exceed 10% by weight of the iso-alpha acids. Even more preferably the amount of reduced iso-alpha acids does not exceed 3% by weight of the iso-alpha acids.

(26) The light-stable hop extract of the present invention typically comprises at least 20 mg/l of the hop derived substances. More preferably, the light-stable hop extract contains at least 80 mg/l of the hop derived substances, most preferably at least 150 mg/l of said hop derived substances.

(27) The light-stable hop extract preferably is a hop extract that has been isolated from hop by means of extraction of with liquid or supercritical carbon dioxide.

(28) The light-stable hop extract of the present invention preferably is a pre-isomerised hop extract, more preferably a pre-isomerised hop extract containing iso-alpha acids and alpha acids in a weight ratio that exceeds 10:1, most preferably in a weight ratio that exceeds 20:1.

(29) The light-stable hop extract preferably has a water content of at least 30 wt. %, more preferably a water content of at least 50 wt. % and most preferably of at least 70 wt. %.

(30) Another aspect of the present invention relates to a beer comprising light-stable hop extract, said beer containing at least 40 g/l riboflavin and at least 0.1 mg/l of one or more hop derived substances represented by the following formula (I):

(31) ##STR00006##
wherein RCH(CH.sub.3).sub.2, CH(CH.sub.3)CH.sub.2CH.sub.3 or CH.sub.2CH(CH.sub.3).sub.2.

(32) As explained herein before, riboflavin plays an important role in the light-induced formation of 3-MBT in beer. Riboflavin is naturally present in beer and undergoes extremely rapid photolysis. As a matter of fact, in ordinary beer riboflavin is photolysed much more rapidly than iso-alpha acids. Thus, in light-struck beer riboflavin content is usually reduced to only a fraction of the original content even before a significant fraction of the iso-alpha acids has been photolysed.

(33) The light-stable beer of the present invention differs from ordinary beer in that it contains at least 0.1 mg/l of the aforementioned one or more hop derived substances. This light-stable beer differs from light-struck beer in that it simultaneously contains at least 0.1 mg/l of these hop derived substances and at least 40 g/l riboflavin.

(34) The beer of the present invention typically contains at least 0.2 mg/l, more preferably at least 0.4 mg/l, and even more preferably at least 1 mg/l of the one or more hop derived substances. Typically the concentration of the one or more photolysed hop substances in the beer does not exceed 50 mg/l. More preferably said concentration does not exceed 40 mg/l, even more preferably it does not exceed 30 mg/l and most preferably it does not exceed 20 mg/l.

(35) The light-stable beer preferably contains at least 0.03 mg/l, more preferably at least 0.1 mg/l and most preferably at least 0.3 mg/l of the isocohumulone derived substance.

(36) The isocohumulone derived substance Co2 is preferably contained in the light-stable beer in a concentration of at least 0.02 mg/l, more preferably at least 0.07 mg/l and most preferably of at least 0.2 mg/l.

(37) The light-stable beer preferably contains at least 0.05 mg/l, more preferably at least 0.2 mg/l and most preferably at least 0.5 mg/l of the isohumulone derived substance.

(38) The riboflavin content of the light-stable beer preferably is at least 60 g/l. Most preferably, the riboflavin content is in the range of 80 to 2,000 g/l.

(39) According to a particularly preferred embodiment, the one or more hop derived substances and riboflavin are present in the light-stable beer in a weight ratio that does not exceed 200:1, more preferably in a weight ratio that is in the range of 1:1 to 100:1 and most preferably in the range of 2:1 to 50:1.

(40) The light-stable beer typically contains the isocohumulone derived substance and riboflavin in a weight ratio that does not exceed 100:1, more preferably in a weight ratio of 1:2 to 50:1, most preferably of 1:1 to 40:1.

(41) The light-stable beer typically contains the isohumulone derived substance and riboflavin in a weight ratio that does not exceed 160:1, more preferably in a weight ratio of 1:1 to 80:1, most preferably of 2:1 to 60:1.

(42) The light-stable beer of the present invention typically contains at least 0.1 mg/l, more preferably at least 0.3 mg/l, even more preferably at least 0.6 mg/l and most preferably at least 1 mg/l of iso-alpha acids. Typically the level of iso-alpha acids in the beer will not exceed 30 mg/l.

(43) The one or more hop derived substances are preferably contained in the light-stable beer in a concentration of at least 1%, more preferably of at least 3%, even more preferably at least 5% and most preferably of at least 10% by weight of the iso-alpha acids that are also contained in the beer.

(44) The light-stable beer of the present invention typically contains less than 100 ng/l 3-methyl-2-butene-1-thiol (3-MBT). Even more preferably the 3-MBT content is less than 50 ng/l, most preferably less than 30 ng/l. The concentration of 3-MBT can suitably be determined by means of the method described by Hughes et al. (Hughes P. S., Burke S. and Meacham A. E. (1997) Aspects of the lightstruck character of beer. Institute of Brewing, Proceedings of the 6th Central and South Africa Section, pp. 123-128).

(45) A further aspect of the present invention relates to a process of preparing a beer as defined herein before, said process comprising introducing a light-stable hop extract as defined herein before.

(46) The light-stable hop extract is preferably added to wort or beer before clarification, i.e. before removal of entrained solids and yeast from the fermented beer. Typically, clarification of fermented beer is achieved by means of filtration.

(47) In the aforementioned process the light-stable hop extract is preferably introduced into the wort or beer in a concentration of at least 2 mg/l, more preferably in a concentration of 5-200 mg/l, most preferably in a concentration of 10-150 mg/l.

(48) Following addition of the light-stable hop extract to the wort, the wort is subjected to further processing steps, including: fermenting the wort with the help of brewer's yeast; clarifying the fermented beer; and packaging.

(49) Finally, the present invention provides a method of preparing a light-stable hop extract, said method comprising: providing a pre-isomerised hop extract comprising at least 10%, preferably at least 20% and most preferably at least 40% of iso-alpha acids by weight of dry matter, illuminating the pre-isomerised hop extract, optionally after dilution of the pre-isomerised hop extract, to obtain a light-stable hop extract as defined herein before.

(50) According to a particularly preferred embodiment, the pre-isomerised hop extract is illuminated with light having a maximum intensity at a wavelength in the range of 200-800 nm, more preferably in the range of 250-600 nm, most preferably of 300-500 nm.

(51) The illumination intensity employed in the present process preferably exceeds 50 W/m.sup.2. More preferably, said illumination intensity exceeds 100 W/m.sup.2, most preferably it exceeds 200 W/m.sup.2.

(52) The pre-isomerised hop extract is typically illuminated with the aforementioned illumination intensity for at least 30 minutes, more preferably for at least 1 hour and most preferably for 2-48 hours.

(53) During illumination the temperature of the hop extract typically remains within the range of 0-100 C., more preferably of 15-80 C.

(54) The inventors have found that particularly good results can be obtained if the pre-isomerised hop extract is exposed to illumination after being diluted with water. Accordingly, in accordance with a particularly preferred embodiment, the present method comprises the steps of: diluting the pre-isomerised extract with water to produce an aqueous solution; and illuminating an aqueous solution of the pre-isomerised hop extract.

(55) The aqueous diluted solution of the pre-isomerised hop extract typically has an iso-alpha acid content in the range of 0.2-200 g/l, more preferably of 0.5-70 g/l and most preferably 1-25 g/l when the illuminations starts.

(56) The aqueous diluted solution of the pre-isomerised hop extract typically contains at least 80 wt. % water. Even more preferably said dilution contains at least 90 wt. % water. Most preferably, at least 95 wt. % water.

(57) The invention is further illustrated by the following non-limiting examples.

EXAMPLES

(58) Method of Determining the Concentration of Hop Derived Substances

(59) The concentrations of 4 different hop derived substances represented by formula (I) can be determined by means of UPLC-MS using the procedure described below. These 4 hop derived substances include two isocohumulone derived substances (referred to as Co1 and Co2) and two isohumulone derived substance (referred to as N1 and N2). Typical retention times of these substances in the UPLC-MS method described below are listed below.

(60) TABLE-US-00001 Retention time Substance (min.) Co1 6.87 Co2 7.99 N1 9.08 N2 9.99

(61) The mass spectra of these hop derived substances are shown in FIGS. 1-4.

(62) The concentration of each hop derived substance is determined on the basis of calibration curves for each of the hop derived substances. These hop derived substances can be isolated in highly pure form from illuminated pre-isomerised hop extract by means of preparative UPLC.

(63) The calibration curves for the hop derived substances are determined using the detector conditions described below.

(64) The equipment, materials and conditions described below can be used to determine the concentrations of the aforementioned hop derived substances.

(65) Equipment: UPLC system: Acquity UPLC (Waters) equipped with a BEH C18 column (1.7 m, 2.1 mm150 mm; Waters product number: 186002353) Detector: XEVO TQ-S mass spectrometer (Waters)

(66) Chemicals: Milli-Q Ultrapure Water Acetonitrile 99.9% (JT-Baker: 9853-02) Formic acid 98% (Sigma-Aldrich product number: 33015)

(67) UPLC Instrument Conditions:

(68) Column temperature: 60 C.

(69) Injection volume: 1 L

(70) Sample temperature: 10 C.

(71) Run time: 25 min

(72) Eluent A=1000 mL Ultrapure water+1 mL formic acid

(73) Eluent B=1000 mL acetonitrile+1 mL formic acid

(74) Gradient:

(75) TABLE-US-00002 Time (min) Flow (mL/min) % A % B 0.0 0.25 95 5 10 0.25 59 41 11 0.25 95 5 25 0.25 95 5

(76) Detector Conditions:

(77) Analytical method is set-up in negative scan mode (ES) and Multiple Reaction Monitoring (MRM) modes.

(78) MS Settings:

(79) TABLE-US-00003 Polarity ES Capilllary (kV) 2.5 Source Temperature ( C.) 150 Desolvation temperature ( C.) 600 Cone gas flow (L/Hr) 150 Desolvation gas flow (L/Hr) 1000 Collision gas flow (mL/min) 0.22

(80) Multiple Reaction Monitoring (MRM) Modes:

(81) TABLE-US-00004 Parent Daughter Coll (m/z) (m/z) (eV) Co1 and Co2 267 195 20 N1 and N2 281 209 20

(82) Samples are degassed prior to analysis.

(83) Method of Determining the Concentration of Riboflavin

(84) The concentration of riboflavin in beer can be determined by means of UPLC-FLR using equipment, materials and conditions as described below.

(85) Equipment: UPLC system: Acquity UPLC (Waters) equipped with a BEH C18 column (1.7 m, 2.1 mm150 mm; Waters product number: 186002353) Detector: Acquity Fluorescence (FLR) detector (Waters)

(86) Chemicals: Milli-Q Ultrapure Water Acetonitrile 99.9% (Sigma Aldrich product number: 34998) Phosphoric acid 85.0% (Sigma Aldrich product number: 30417) Riboflavin (Sigma Aldrich product number: R-7649) Sodium dihydrogen phosphate monohydrate (Merck product number: 106346) pH buffer 2.7 (7.5 g sodium dihydrogen phosphate monohydrate in 200 mL Ultrapure water+1 mL Phosphoric acid in 1000 mL Ultrapure water)

(87) UPLC Instrument Conditions: Column temperature: 40 C. Injection volume: 10 L Sample temperature: 10 C. Run time: 15 min Eluens A=pH buffer 2.7 Eluens B=acetonitrile

(88) Gradient:

(89) TABLE-US-00005 Time (min) Flow (mL/min) % A % B 0.00 0.20 95 5 10.0 0.20 95 5 10.5 0.20 15 85 12.0 0.20 15 85 12.2 0.20 95 5 15.0 0.20 95 5

(90) Detector Conditions: .sub.ex=444 nm .sub.em=525 nm

(91) Samples are degassed prior to analysis.

Example 1

(92) A pre-isomerised hop extract (so-called Isohop obtained from Barth-Haas Group) was used as a starting material. This hop extract had the following characteristics (according to the product description sheet from Barth-Haas Group): contains 300.5 wt % iso-alpha acids contains <0.7% alpha acids contains <0.3% beta acids

(93) The pre-isomerised hop extract was diluted with Milli-Q Ultrapure Water (1:50 w/w). 16 mL of the diluted hop extract was introduced into a glass tube with screw cap (Duran glass, tube diameter is 16 mm, tube length is 160 mm). 30 of these glass tubes were simultaneously illuminated for a period of 32 hours inside a Suntest XLS+ device (ATLAS), using a Xenon lamp. During illumination, the following conditions were applicable: Power of Xenon lamp is 1700 W Tubes were horizontally positioned inside the Suntest XLS+ device Distance between glass tubes and lamp is 25 cm Amount of irradiance at sample level was set at 765 W/m.sup.2 Temperature of diluted hop extract increases from ambient to circa 50 C. (no cooling nor heating was intentionally applied during illumination)

(94) Before and after illumination, the concentrations of iso-alpha acids and hop derived substances in the hop extract were determined. Determination of iso-alpha acids in the hop extract was performed according to the method described by the European Brewery Convention (EBC) in 2005: Method 7.8: Iso-alpha-, alpha- and beta-acids in hops, hop powder products and hop extracts (HPLC method). Determination of the concentration of the hop derived substances in the extract was performed according to the method described above. The results of these analyses are shown in Table 2:

(95) TABLE-US-00006 TABLE 2 Iso- alpha Hop derived substances acids Co1 Co2 N1 N2 Sum (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) Hop Extract 5808 <0.01 <0.01 <0.01 <0.01 <0.01 Light- 339 65 264 174 372 875 Stable Hop Extract

Example 2

(96) The illuminated and non-illuminated hop extracts of Example 1 were added to unhopped beer (300 mL unhopped beer in green bottle). A first beer (reference beer) was prepared by adding 20 mg/L of the non-illuminated hop extract. A second beer (light-stable beer) was prepared by adding 60 mg/L of the illuminated hop extract. The illuminated hop extract was applied in a higher concentration in order to compensate for the loss in bitter intensity that had occurred as a result of the illumination. The flavour profile of the beer containing the illuminated hop extract had a flavour profile that was very similar to that of the beer containing the non-illuminated hop extract.

(97) Both beers were exposed to artificial sunlight by putting the bottles horizontally in the Suntest XLS+ device and illuminating them for a period of 24 hours. During illumination, the same conditions were applied as in Example 1.

(98) Before and during exposure to the artificial sunlight the concentrations of the following substances were determined in both beers: the hop derived substances of formula (I), iso-alpha acids, riboflavin, and 3-MBT.

(99) Determination of iso-alpha acids in beer was performed according to the method described by the American Society of Brewing Chemists (ASBC) in 2009 (Methods of Analysis, 14th Edition): Method Beer 23 (section E: Iso-alpha acids in beer by HPLC). The 3-MBT content was determined using the method described by Hughes et al. (Aspects of the lightstruck character of beer. Institute of Brewing, Proceedings of the 6.sup.th Central and South Africa Section (1997), pp. 123-128). Determination of the concentration of the hop derived substances and riboflavin in beer was performed according to the methods described above.

(100) The results of these analyses are summarised in Table 3:

(101) TABLE-US-00007 TABLE 3 Iso-alpha Hop derived substances acids Co1 Co2 N1 N2 Sum Riboflavin MBT (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (g/L) (ng/L) Reference beer 0 h illumination 19.2 <0.01 <0.01 <0.01 <0.01 <0.01 318 7 2 h illumination 18.8 0.01 0.02 0.03 0.04 0.11 16 309 6 h illumination 17.8 0.05 0.08 0.11 0.15 0.39 2.8 660 24 h illumination 16.0 0.19 0.28 0.42 0.54 1.42 0.3 2072 Light-stable beer 0 h illumination 4.5 0.53 2.32 1.65 3.54 8.04 313 8 2 h illumination 4.4 0.56 2.29 1.66 3.45 7.95 15 74 6 h illumination 4.2 0.61 2.20 1.77 3.29 7.87 2.0 137 24 h illumination 3.6 0.86 2.19 2.18 3.18 8.41 0.4 506