When Beer Goes Sour: An NMR Investigation ADAM DICAPRIO PROCESS NMR ASSOCIATES 87A SAND PIT ROAD DANBURY, CT 06810 What is Sour Beer?
Wikipedia says:
“Sour beer is a beer style characterized by an intentionally acidic, tart, sour taste.”
“Wild Brews: Beer beyond the Influence of Brewer’s Yeast”
Category 17 of the Beer Judge Certification Program
Encompasses: Berliner Weisse, Flanders Red Ale, Flanders Brown Ale, Lambic, Fruit Lambic, Gueuze What goes in to a sour beer?
Grain Malted Barley, Unmalted Wheat, Specialty Malts
Dextrins, Dextrins, Dextrins
Sikaru beer (3000 B.C.) – 62.5% Barley Malt + 37.5% Raw Wheat2
Modern Lambic – Brasserie Cantillon recipe – 65% Barley Malt + 35% Raw Wheat2 Hops http://www.newbelgium.com/Community/Blog/12-03-23/Who-wants-more-sour-beer.aspx Aged & Oxidized Aging Vessels – A sour beers home for up to a full century Oak Barrels (French & American) Oak Foudre Stainless Steel Tank
http://www.belgianbeermagazine.com/oud-beersel-brewery/ Who goes in to a sour beer?
Dozens of organisms2,3
Bacteria
Enterobacteriaceae
Citrobacter spp., Enterobacter spp., Klebsiella spp., Hafnia spp.
Lactobacillaceae
Pediococcus spp., Lactobacillus spp.,
Acetobacter spp.
Klebsiella spp.
Yeasts
Kloeckera apiculata
Saccharomyces spp.
Brettanomyces spp.
Pichia spp.
Candida spp.
Hansenula spp.
Cryptococcus spp. Why is Sour Beer Sour?
Straight Lambic, Flanders Ales, Gueuze, Berliner Weisse
Lactic, Acetic, Succinic Acid1
85% - 10% - 5%
Fruit Lambics1
Cherries, Grapes – Malic Acid
Raspberries – Citric Acid Chemistry of Sour Beers
Application of Quantitative NMR to Biologically Acidified Mashes
Quantitative NMR and Descriptive Chemistry of American Wild Ales and genuine Belgian Lambic Berliner Weisse & Biological Acidification
Reinheitsgebot of 1516
Beer can contain only malt, hops & water
Unmalted wheat and yeast added in the Provisional Law of 19964
Artificial alteration of pH is illegal5
Development of Biological Acidification/Sour Mashing
Utilization of native microbes for pH adjustment6
Perform Hold Cool to Starch Innoculate Temperature ~120°F Conversion (120°F) Temperature Dependence of the Sour Mash Technique
Goal:
Does the “magic” temperature of 120°F have a chemical significance?
Record and quantify sour metabolites & contaminant products as a function of sour mash temperature
Determine wt% of metabolites using Maleic Acid internal standard & manual integration
Lactic Acid
Acetic Acid (contaminant)
Succinic Acid
Ethanol
γ-Amino Butyric Acid (contaminant) Malt-040-H.esp Ethanol
Maleic Acid HOD Sugar Anomeric Region Lactic Acid
Acetic Acid
0.0015 B-Glucose
0.0010 a-Glucose Lactic Acid
Normalized Intensity Normalized
0.0005 Succinic Acid a(1-4) Dextrins 2,3-butanediol Pyruvic Acid
0
6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 Chemical Shift (ppm)
Straight Run of 95°F Sour mash; Assignments from Rodrigues et al. 2010 Malt-025-H.esp HOD
0.11
0.10 Lactic Acid
0.09
0.08 Sugar Anomeric Region 0.07 Maleic Acid
Ethanol 0.06 B-Glucose Acetic Acid 0.05 a-Glucose
Normalized Intensity Normalized 0.04
0.03 Lactic Acid 2,3-Butanediol 0.02 a(1-4) Dextrins Succinic Acid TMSP 0.01
0
-0.01
6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 Chemical Shift (ppm) Freeze Dried Run of 95°F sour Mash; Assignments from Rodrigues et al. 2010 Absolute Metabolite Proportions
16.00 1.4 Metabolite Weight % vs. Temperature 1.2 Weight % Ethanol 1 14.00 0.8 0.6 0.4
12.00 0.2 Percent by Mass by Percent 0 90 100 110 120 130 140 10.00 Temperature (°F)
8.00
6.00
4.00
2.00
0.00 90 95 100 105 110 115 120 125 130 135 140
Lactic Acid Acetic Acid Succinic Acid Poly. (Lactic Acid) Poly. (Acetic Acid) Poly. (Succinic Acid) Relative Proportions Lactic:Acetic Lactic:Succinic 16.00 300.0
14.00 250.0
12.00 R² = 0.9941 200.0 10.00 R² = 0.9676 8.00 150.0
6.00
100.0 WT % LACTIC / WT % ACETIC % WT / LACTIC % WT
4.00 SUCCINIC % WT / LACTIC % WT
50.0 2.00
0.00 0.0 90 100 110 120 130 140 95 105 115 125 135 TEMPERATURE (°F) TEMPERATURE Conclusions
120°F is sub-optimal for acid production Around 120°F Lactic acid reaches a relative maximum Lactic good, Acetic bad Aim is pH adjustment, not flavor adjustment Lambics of Belgium & Lambic-Styles of the USA
What’s the difference?
Lambic – From the Pajottenland / Senne River Valley Region of Belgium
American likenesses styled as “American Wild Ale (AWA)” or “American Coolship Ale (ACA)”
Different Microbial Community
Follow same general succession
ACA involves a more diverse community of Lactic Acid Bacteria and Minority Yeasts3 The Chemistry of Sour Beers
Goals
Comparative analysis of organic acids using quantitative NMR
Manually integrated against a known mass of Maleic Acid
Lactic Acid, Acetic Acid, Succinic Acid, Citric Acid, Malic Acid
Analyze linear and branched dextrin ratios among multiple styles
Utilize multivariate analysis to discriminate multiple styles of sour beer Allagash-014-H.espMaleic Acid HOD Ethanol Ethanol
Lactic Acid
0.0010
Acetic Acid
0.0005 Lactic Acid Normalized Intensity Normalized Citric Acid & Malic Acid (if present)
Succinic Acid
0
6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 Chemical Shift (ppm) Drie Fonteinen Oude Gueuze Straight Run; Assignments from Rodrigues et al. 2010 Allagash-014-H_FD.esp Sugar Anomeric Region Lactic Acid
Lactic Acid Ethanol
Maleic Acid Residual Ethanol 2,3-butanediol
0.007 Valine, Leucine, Isoleucine
0.006 Proline
0.005 a(1-4) Maltodextrin Citric Acid & Malic Acid (if present)
Normalized Intensity Normalized 0.004 a(1-6) Maltodextrin Aromatic Amino Acids Proline Arginine Residual Phenols 0.003 Benzoic Acids a-Glucose Asparagine Alanine
0.002 Aromatic Amino Acids B-Glucose Residual Phenols Pyruvic Acid 0.001 Benzoic Acids
8.5 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 Chemical Shift (ppm) Freeze dried Run of Drie Fonteinen Oude Gueuze; Assignments from Rodrigues et al. 2010, Rodrigues & Gil 2011, & Nord et al. 2004 Allagash-005-H_FD.esp Allagash-006-H_FD.esp Lactic Acid 0.060
0.055 Framboise-Style Kriek-Style 0.030 Lactic Acid 0.050
0.045 0.025
0.040
0.020 0.035
Acetic Acid 0.030 Acetic Acid 0.015 0.025
Normalized Intensity Normalized
Normalized Intensity Normalized Citric Acid 0.020 Malic Acid 0.010 Succinic Acid 0.015 Succinic Acid
0.010 0.005
0.005
3.0 2.5 2.0 1.5 3.0 2.5 2.0 1.5 Chemical Shift (ppm) Chemical Shift (ppm)
Allagash-004-H_FD.esp Lactic Acid
0.030 Gueuze-Style 0.025
0.020
0.015
Normalized Intensity Normalized
0.010 Acetic Acid
Succinic Acid 0.005 No Malic Acid Little to No Citric Acid
3.0 2.5 2.0 1.5 Chemical Shift (ppm) American Geuze-Style American Framboise- Acid Differences Style 3%
20% Beer LA (mg/L) AA (mg/L) SA (mg/L) CA (mg/L) MA (mg/L) 35% 35% American Geuze- 5386.0 1410.0 238.5 0 0 Style American Framboise 3896.7 2972.1 394.6 3890.7 0 3% -Style 77% 27% American 4682.8 1965.7 423.4 0 3777.8 Kriek-Style Lactic Acetic Succinic Citric Boone Lactic Acetic Succinic Mariage 4506.5 488.1 217.0 0 0 Parfait 2009 Belgian Geuze American Kriek-Style Oude Geuze 3497.8 454.1 175.2 0 0 4% Vieille 11% Geuze Fond 6807.8 698.6 218.8 0 0 35% Tradition 43% Drie Fonteinen 5137.6 865.9 234.6 0 0 A Drie Fonteinen 5389.9 917.7 228.9 0 0 4% B 85% 18%
Lactic Acetic Succinic Lactic Acetic Succinic Malic Dextrin Ratios
Ratio of α(1-4) Maltodextrin to α(1-6) “Degree of Fermentation” Maltodextrin by Style Dependent on: 7
Strain 6) 6) - 6
Style (1
Α 5
/ / Ingredients 4
3
2
1 MALTODEXTRIN
MALTODEXTRIN 0
4) 4)
-
(1 Α
STYLE Multivariate Analysis – Principal Component Analysis
Segregate based largely on sugar detail Saiso Saisonsns Belgi Bel.an Foudre Independent of Foudr ingredients e Beer Belgi Lambic an Geuz IPA + es Hybri Lager d IPAs + Lager Beer 100%100% Brett. ACA Ameri Ameri Brett can can Beers Cools Foudr hip Am.e Foudre Beers Beer Conclusions
ACAs & Belgian Lambics have differing acid profiles
Ratio of linear and branched maltodextrins can be used to differentiate styles
Multivariate analysis can differentiate between ACAs, Belgian Lambics and 6 other styles References 1. Sparrow, J. (2005). Wild brews: Beer Beyond the Influence of Brewer’s Yeast, (Strong, G., Ed.), Brewers Publications, Boulder, CO.
2. Guinard, J. X. (1990). Lambic, (Thomas, V., Ed.), Brewers Publications, Boulder, CO.
3. Bokulich, N. A., Bamforth, C. W., Mills, D. A. (2012). Brewhouse-Resident Microbiota Are Responsible for Multi-Stage Fermentation of American Coolship Ale, PLoS One. 7:4, 1-11.
4. Dornbusch, H., Heyse, K. U. (2012) Reinheitsgebot, in the Oxford Companion to Beer, (Oliver, G., Ed.), pp. 691-693, Oxford University Press, Oxford.
5. Narziss, L. (1984) The German Beer Law, J. Inst. Brew. 90, 351-358.
6. Sour Mashing: Techniques, Brew Your Own Magazine. http://byo.com/all-grain- brewing/item/1691-sour-mashing-techniques (last accessed July 2013).
7. Rodrigues, J. E., Erny, G. L., Barros, A. S., et al. (2010). Quantification of organic acids in beer by nuclear magnetic resonance (NMR)-based methods, Anal. Chim. Acta. 674(2):166- 175.
8. Rodrigues, J.E., Gil, A. M. (2012). NMR methods for beer characterization and quality control, Magn. Reson. Chem. 49: S37-S45.
9. Nord, L. I., Vaag, P., Duus, J. O. (2004). Quantification of Organic and Amino Acids in Beer by 1H NMR Spectroscopy, Anal. Chem. 76(16):4790-4798.