Method of producing beer having a tailored flavour profile
11242501 · 2022-02-08
Assignee
Inventors
Cpc classification
C12C11/11
CHEMISTRY; METALLURGY
International classification
C12C11/11
CHEMISTRY; METALLURGY
Abstract
A method of producing beer having a tailored flavour profile is provided comprising the successive steps of: (a) fermenting wort containing fermentable sugars with yeast to produce beer containing 1-10 vol. % ethanol and flavour substances diacetyl; acetaldehyde; dimethyl sulfide; ethyl acetate; isoamyl acetate; ethyl valerate; ethyl hexanoate; iso-amyl alcohol and 2-methylbutan-1-ol; (b) contacting the fermenting wort or beer with porous adsorbent particles, selectively adsorbing the beer flavour esters ethyl acetate, ethyl hexanoate, ethyl valerate and isoamyl acetate; (c) separating the adsorbent particles; (d) desorbing a portion of the beer flavour esters from the adsorbent particles; and (e) adding a fraction of the desorbed beer flavour esters to the flavour adjusted beer or to another beer, wherein the amount of beer flavour esters added is 5-95 wt. % of the amount of beer flavour esters removed by the adsorbent particles.
Claims
1. A method of producing beer, comprising the successive steps of: (a) fermenting a wort containing fermentable sugars with an active yeast to produce a beer comprising 1-10 vol. % ethanol and beer flavour substances diacetyl, acetaldehyde, dimethyl sulphide, ethyl acetate, isoamyl acetate, ethyl valerate, ethyl hexanoate, iso-amyl alcohol, and 2-methylbutan-1-ol; (b) contacting the fermenting wort or the beer with porous adsorbent particles to selectively adsorb one or more surplus flavour substances selected from diacetyl, acetaldehyde, and dimethyl sulphide, the adsorbent particles having a high affinity for one or more of the surplus flavour substances and a lower affinity for ethanol and the other beer flavour substances; and (c) separating the adsorbent particles containing the one or more adsorbed surplus flavour substances from the beer to produce a flavour adjusted beer comprising 1-10 vol. % ethanol; wherein the porous adsorbent particles comprise an adsorbent containing amine functionalities; and wherein the adsorbent particles' affinity ratio Oi for at least one of the surplus flavour substances exceeds 5; the affinity ratio θ.sub.1 for surplus flavour substance i being defined by the following equation: θ.sub.i=K.sub.i/K.sub.ethanol, wherein: (i) K.sub.i represents the adsorbent particles' affinity constant for surplus flavour substance i; and (ii) K.sub.ethanol represents the adsorbent particles' affinity constant for ethanol.
2. The method according to claim 1, wherein the beer is contacted with the porous adsorbent particles.
3. The method according to claim 2, wherein the beer is contacted with the adsorbent particles after the beer has been heated to a temperature of at least 60° C. for at least 5 minutes.
4. The method according to claim 1, wherein the affinity ratio θ.sub.i for diacetyl exceeds 5.
5. The method according to claim 4, wherein the affinity ratio θ.sub.i for diacetyl exceeds 10.
6. The method according to claim 1, wherein the adsorbent particles have an affinity constant for diacetyl that is at least 3 times higher than the particles' affinity constant for ethyl acetate.
7. The method according to claim 1, wherein the affinity ratio θ.sub.i for acetaldehyde exceeds 5.
8. The method according to claim 7, wherein the affinity ratio θ.sub.i for acetaldehyde exceeds 10.
9. The method according to claim 1, wherein the affinity ratio θ.sub.i for dimethyl sulfide exceeds 5.
10. The method according to claim 9, wherein the affinity ratio θ.sub.i for dimethyl sulfide exceeds 10.
11. The method according to claim 1, wherein yeast is separated from the beer before the beer is contacted with the adsorbent particles.
12. The method according to claim 1, wherein yeast and the adsorbent particles are simultaneously separated from the beer to produce the flavour adjusted beer.
13. The method according to claim 1, wherein the adsorbent particles consist of polymer or the surface of the adsorbent particles consists of polymer.
14. The method according to claim 1, wherein the adsorbent containing amine functionalities are selected from chitosan, Sevalamer™ (copolymer of 2-(chloromethyl)oxirane(epichlorohydrin) and prop-2-en-1-amine) and Siliabond™ amine functionalised silica gels.
15. The method according to claim 1, wherein the adsorbent particles have specific surface area of at least 50 m.sup.2/g.
16. The method according to claim 1, wherein at least 80 wt. % of the adsorbent particles has a diameter in the range of 5-5,000 μm.
Description
EXAMPLES
Example 1
(1) Experiments were conducted to study the interaction of 5 beer flavour substances (Ethyl Acetate, Diacetyl, Isobutyl Alcohol, Isoamyl Acetate, Isoamyl Alcohol) in a co-solvent mixture of ethanol/water with different commercially available food-grade resins under conditions that are representative of those found in beer.
(2) Below the results are summarized for three different resins that showed a high affinity for Isoamyl Acetate and a clear differentiation in affinities for the 5 flavour substances tested.
(3) A model solution containing the 5 flavour substances (each in approximately a concentration of 2 g/L) in 4 w/v % mixtures of ethanol/water was prepared for the determination of adsorption isotherms.
(4) Three food-grade resins were used for the tests:
(5) Amberlite XAD16N (20-60) mesh, purchased from Sigm-Aldrich
(6) XAD7 HP, purchased from Sigma-Aldrich;
(7) Sepabeads SP20-SS, purchased from Sigma-Aldrich (Supelco)
(8) Microtiter plates (96 microtiter deep-well plate filter 2 ml ex Millipore USA) were filled with the selected resins, mass of each resin being equal to mass of the calibrated volume of the Titan 96 well Resin loader (Radleys. UK) (0.0874 g of the resin for Sepabeads SP20-SS, 0.0964 g for XAD16N and 0.0751 g for XAD7HP. The resins were pretreated by washing steps with methanol, followed by an equilibration step with water.
(9) After the pretreatment, the deep-well plates including the resins, were loaded with 1800 μL of different dilutions (dilution factors of 0.67) of the beer flavour solutions (different dilutions of the prepared samples are also added to different wells of the 96-well micro-titer plate as blank to account for the effect of evaporation). Next, the microtiter plate was covered with adhesive aluminum foil to minimize evaporation. The micro-titer plates were stirred at 300 rpm for 30 minutes on a thermo-shaker whilst keeping the temperature at 4° C. to minimize evaporation. Next, the contents of the deep well filter plates were centrifuged into a collecting deep-well plate (VWR International USA) and the collected bulk liquid, and the blank samples were separated for subsequent GC-analysis.
(10) The samples were analyzed using a gas chromatograph (Agilent technologies 6890N series, USA) coupled with FID, and equipped with a Zebron ZB-WAX Plus 20 m×0.18 mm ID×0.18 μm df column. As the carrier gas, Helium was used in the system. The chromatogram showed retention times of 2.4, 2.9, 4.5, 4.8, 6.4, and 2.6 minutes for Ethyl Acetate, Diacetyl, Isobutyl Alcohol, Isoamyl Acetate, Isoamyl Alcohol, and Ethanol, respectively.
(11) To predict the competitive adsorption behaviour of the tested beer flavour substances in a mixture, a multicomponent Langmuir adsorption isotherm model (equation 1) was used: (Sevillano D M, van der Wielen L A M, Hooshyar N, Ottens M., Resin selection for the separation of caffeine from green tea catechins, Food and Bioproducts Processing, 92 (2), 192-198, 2014; Tefera, D. T., Z. Hashisho, J. H. Philips, J. E. Anderson and M. Nichols (2014). Modeling Competitive adsorption of mixtures of volatile organic compounds in a fixed bed of beaded activated carbon, Environmental Science & Technology 48: 5108-5117, 2014).
(12)
(13) The multi-component adsorption isotherm parameters were regressed for the tested flavour substances from their experimental adsorption on the tested resins.
BRIEF DESCRIPTION OF THE FIGURES
(14) The multi-component adsorption isotherm parameters were regressed for the tested flavour substances from their experimental adsorption on the tested resins. For each of the tested resins the isotherms for the different flavour substances are shown in
(15)
(16)
(17)
(18)
(19)
(20)
(21) In addition, for each of the resins the calculated loads were plotted versus experimental loads and depicted in the Pareto plots shown in
(22)
(23)
(24)
(25) The affinity constant (Ki; Ki=(q/c)lim c.fwdarw.0; being the initial slope of the isotherm) was obtained via regressing the multi-component Langmuir isotherm parameters from experimental data from batch uptake experiments using MATLAB software version 8.0.0.873. The regressed affinity constants (in L.g_resin.sup.−1) are shown in Table 1.
(26) TABLE-US-00002 TABLE 1 Sepabeads SP20-SS XAD16N XAD7HP Ethyl acetate 0.0857 0.0245 0.0084 Diacetyl 0.0025 0.0047 0.0019 Isobutyl alcohol 0.0041 0.0052 0.0037 Isoamyl acetate 7.0604 0.1557 0.0500 Isoamyl alcohol 0.0175 0.0280 0.0045 Ethanol 0.0001 0.0002 0.0001
Example 2
(27) In a typical process, lager beer is produced by fermentation followed by a conditioning step at low temperature (<4° C.) for several days. The beer is subsequently filtered to remove visible yeast cells and protein agglomerates which cause turbidity, by a clarifying filtration step.
(28) The beer contains 5% (v/v) ethanol, 25 mg/l ethyl acetate and 4 mg/l isoamyacetate, which implies that the ester ratio ethylacetate/isoamylacetate equals 6.25.
(29) The beer is mixed with adsorbent particles (Amberlite XAD7HP, 10 g per hl of beer). After the completion of the adsorption step, the beer containing the adsorbent particles is passed over a filter with a filter mesh which is sufficiently small to retain these adsorbent particles.
(30) Analysis of the beer after removal of the adsorbent particles shows that concentration levels of both ethyl acetate and isoamyl acetate have been reduced by the contacting with the adsorbent particles. The adsorbent particles are found to have had a stronger affinity of isoamyacetate than ethyl acetate as the ratio of ethyl acetate over isoamyl acetate is increased by the contacting with the adsorbent particles to a value of approximately 10. Also the flavour profile of the beer is changed significantly as a result of the treatment with adsorbent particles.
Example 3
(31) Example 2 is repeated, except that this time the adsorbent particles are collected from the filter mesh and transferred into an elution column. Next, the bed of adsorbent particles is eluted with a mixture of beer and ethanol.
(32) During elution both temperature of the eluent mixture and the ethanol content of the mixture are varied. During elution fractions of eluate are collected. The concentrations of ethyl acetate and isoamyl acetate as well as the weight ratio in which these two esters occur in the collected fractions are found to differ substantially.
(33) Fractions having a relatively high isoamyl acetate content (compared to ethyl acetate content) are added to the original beer to obtain a beer having a higher concentration ratio [isoamyl acetate]/[ethyl acetate] than the original beer.
Example 4
(34) A filtered lager beer was treated with two different particulate adsorbents with functional amine groups (Chitosan and Siliabond® diamine). 100 ml of beer was mixed with the adsorbents under stirring at 3-5° C.
(35) After incubation the mixtures were filtered over a paper filter. The effect of the adsorbent treatment on the concentrations of the beer flavour substances was determined by GC analysis. Tables 2a and 2b show the adsorbent dosage levels that were tested and the impact of the contacting with the adsorbents on ethanol content and on the concentration levels of 6 beer flavour substances.
(36) TABLE-US-00003 TABLE 2a Effect on concentration Chitosan 0.5 g/100 ml 5 g/100 ml Acetaldehyde −12.3% −75.4% Dimethyl sulfide −19.5% −50.6% Ethyl acetate −3.2% −19.3% Iso-amyl acetate −5.9% −24.1% Iso-butanol −5.1% −3.1% Amyl alcohols −3.6% −3.1% Ethanol 0.9% −3.1%
(37) TABLE-US-00004 TABLE 2b Siliabon ® Effect on conc. diamine 2.5 g/100 ml Acetaldehyde −68.4% Dimethyl sulfide −49.4% Ethyl acetate −11.4% Iso-amyl acetate −11.2% Iso-butanol −5.1% Amyl alcohols −6.5% Ethanol 6.9%
Example 4
(38) Adsorption tests were carried out using model solutions containing a mixture of three off-flavour components. An aqueous model solution was prepared containing 20 mg/L acetaldehyde, 20 mg/L diacetyl and 0.3-0.4 mg/L 2-nonenal. 100 ml of this model solution was mixed with particulate adsorbents under stirring at 3-5° C.
(39) After incubation, the mixtures were filtered over a paper filter. The effect of the adsorbent treatment on the concentrations of the beer flavour substances was determined by GC analysis. Table 3 shows the adsorbent dosage levels that were tested and the impact of the contacting with the adsorbents on ethanol content and on the concentration levels of 6 beer flavour substances.
(40) TABLE-US-00005 TABLE 3 Relative reductions in concentration Dosage Acet- Resin g/100 ml aldehyde diacetyl nonenal Chitosan 0.5 −42% .sup. 0 0% 5 −65% −43% −99% Sevalamer 0.5 −79% −31% −83% 5 −100% −94% −100% Siliabond ™ 0.5 .sup. 0 −100% −99% amine Siliabond ™ 0.5 −100% −100% −99% diamine Siliabond ™ 0.5 −88% −60% −100% Tosylhydrazine
Example 5
(41) Samples were taken form a fermenting lager beer at different stages of fermentation and the levels of beer flavour substances in these samples were determined by means of GC-analysis. The results are shown in Table 4
(42) TABLE-US-00006 TABLE 4 Fermen- Normalised Concentrations (C/Cfinal) tation Ethyl time Ethyl Isoamyl Acetal- i- Amyl hexan- (days) acetate acetate dehyde DMS Butanol alcohols oate 1.2 0.07 0.06 0.76 0.75 0.16 0.24 0.05 2.2 0.27 0.30 0.79 0.75 0.32 0.58 0.26 3.2 0.73 0.77 0.75 0.75 0.70 0.89 0.79 4.2 1.00 1.00 1.00 1.00 1.00 1.00 1.00
(43) This data shows that acetaldehyde and dimethyl sulfide are largely formed during the initial stage of fermentation. Also the higher alcohols (iso butyl alcohol and amilic alcohols) are largely formed during the first two days of fermentation whereas the flavour esters are largely formed at the end of the fermentation process (days 3 and 4).
(44) The data indicates that addition of adsorbent particles having affinity for acetaldehyde and/or dimethyl sulfide at the very beginning of the fermentation process and removal of the particles at the end of the first fermentation day will inherently favour selective removal of acetaldehyde and/or dimethyl sulfides as the treatment will have little effect on, for instance, the concentration levels of flavour esters as these are largely formed after the treatment.
Example 6
(45) A lager beer is produced by process that comprises fermentation of wort and removal of yeast from the beer. Next, the beer cooled own and conditioned at a temperature below 4° C., followed by clarification over a clarifying filter. The clarified beer is then heated to a temperature of 65-70° C.) to convert residual acetolactate into diacetyl.
(46) Next, the heated beer is treated with 100 g/hl of Siliabond® diamine to remove diacetyl. After incubation the adsorbent particles are removed by means of filtration.