Hoppy Aroma and Flavor Daniel C. Sharp, M.S. Food Science and Technology Michael Qian, Thomas H. Shellhammer Oregon State University Department of Food Science and Technology
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Hoppy Aroma and Flavor Daniel C. Sharp, M.S. Food Science and Technology Michael Qian, Thomas H. Shellhammer Oregon State University Department of Food Science and Technology
How is beer made?
Barley
Hops Yeast
Water
Hops in Beer: An Overview
Hops in Beer: An Overview
What is Hop Aroma/Flavor? Hoppy aroma and flavor in beer is a product of the coordination of physical, biochemical, and chemical phenomena that occur during brewing and psychophysical phenomena during consumption.
Humulus lupulus fam. Cannabaceae
• Dioecious perennial • Climbing plant (c. 6 meters) • 100+ cultivars
Photo: Indie Hops
Lupulin glands
SEM Image of Lupulin glands Forster, 2001
Hops composition Principle Components Concentration (%w/w) Cellulose + lignin 40.0 - 50.0 Protein 15.0 Alpha acids 2.0 - 17.0 Beta acids 2.0 - 10.0 Water 8.0 - 12.0 Minerals 8.0 Polyphenols and tannins 3.0 - 6.0 Lipids and fatty acids 1.0 - 5.0 Hop oil 0.5 - 3.0 Monosaccharides 2.0 Pectin 2.0
European Brewery Convention Hops and Hop Products, Manual of Good Practice; Getranke - Fachverlag Hans Carl: Nurnberg, Germany, 1997.
Hops composition Principle Components Concentration (%w/w) Cellulose + lignin 40.0 - 50.0 Protein 15.0 Alpha acids 2.0 - 17.0 Beta acids 2.0 - 10.0 Water 8.0 - 12.0 Minerals 8.0 Polyphenols and tannins 3.0 - 6.0 Lipids and fatty acids 1.0 - 5.0 Hop oil 0.5 - 3.0 Monosaccharides 2.0 Pectin 2.0
European Brewery Convention Hops and Hop Products, Manual of Good Practice; Getranke - Fachverlag Hans Carl: Nurnberg, Germany, 1997.
Hop Acids and their solubility
Peacock, 1998
The most important reaction in hop chemistry?
Beer Sample – Iso-alpha acids by HPLC
2.5 5 7.5 10 12
mAU
0
100
200
300
400
DAD1 A, Sig=270,4 Ref=360,100 (VAA 6-18-13\VAA 6-18-13 2013-06-19 12-22-20\002-0301.D)
isocohumulone
isohumulone
isoadhumulone
Measuring Bitterness in Beer Bitterness Units (IBUs) and [iso-α acids] (IAAs) What does the IBU measure? • Whatever gets extracted by iso-octane • Whatever absorbs at 275 nm. • Combined α, β, iso’s, oxidized materials, polyphenols
1 BU ≠ 1 ppm iso-alpha acid
y = 1.2x + 2.0 R² = 0.905
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0
IBU
Iso alpha acids concentration [ppm]
Correlation between total IAA & IBU
Beer Bitterness Key Points
• Most bitterness attributed to isomerization of α-acids during boiling. Different analogs contribute differently.
• Measured by BUs (spectrophotometric ally)
…but 1 BU ≠ 1 ppm iso-alpha acid • Bitterness also comes from other hop material, eg.
Polyphenols, tannins, oil components, oxidations products.
Questions so far?
Design by Victor Algazzali Graphics from http://www.bojensen.net/index.html
Hop Aroma
Table adapted from: Eyres, G.; Dufour, J.
Hops composition Principle Components Concentration (%w/w) Cellulose + lignin 40.0 - 50.0 Protein 15.0 Alpha acids 2.0 - 17.0 Beta acids 2.0 - 10.0 Water 8.0 - 12.0 Minerals 8.0 Polyphenols and tannins 3.0 - 6.0 Lipids and fatty acids 1.0 - 5.0 Hop oil 0.5 - 3.0 Monosaccharides 2.0 Pectin 2.0
European Brewery Convention Hops and Hop Products, Manual of Good Practice; Getranke - Fachverlag Hans Carl: Nurnberg, Germany, 1997.
Essential Oil
Hop Oil Composition
Schönberger, C.; Kostelecky, T. 125th Anniversary Review: The Role of Hops in Brewing. J. Inst. Brew 2011, 117, 259–267.
Hop Oil Composition
Schönberger, C.; Kostelecky, T. 125th Anniversary Review: The Role of Hops in Brewing. J. Inst. Brew 2011, 117, 259–267.
Physical Effects Objective: Identify the effect of hopping regime on the contribution of hop volatiles to hop aroma in beer.
CC
V
Kettle Whirlpool
• Factors • Hopping Regime • Hop Cultivar (Simcoe, Hallertau Mittlefrueh)
• Response • (Chemical) Volatiles • (Sensory) Descriptive Analysis
60 minute boil ~100 C, 20 min 18 C, 48 hours
Stir Bar Sorptive Extraction GC-MS Analysis Target Analytes α-pinene β-pinene 3-carene β-myrcene Limonene p-cymene β-citronellal Linalool β-caryophyllene β-farnesene α-humulene E-citral α-terpineol Z-citral geranyl acetate β-citronellol Nerol E-β-damascenone Geraniol β-ionone Eugenol α-eudesmol β-eudesmol Terpinen-4-ol
Significant Analytes
3-carene
β-myrcene
Linalool
β-farnesene
α-humulene
geranyl acetate
β-citronellol
Geraniol
Eugenol
Terpinen-4-ol
Biochemical Effects
O
HO
OH
OH
OOH
Yeast OH
OHO
HO
HO
OH
OHH2O
Non-Odor Active Odor Active
• Factors – Yeast strain → glycosidase activity
• Response – Change in volatile composition
Homework
HS-SPME GC-MS of Big Sky IPA and Budlight
HS-SPME GC-MS of Big Sky IPA and Budlight
HS-SPME GC-MS of Big Sky IPA and Budlight
β-M
yrce
ne Lina
lool
β-C
itron
ello
l
Ger
anio
l
Big Sky IPA hop aroma – Principle compounds (by conc.)
Compound ~Conc. (ppm) Sensory Threshold Description
Myrcene 0.160 ppm 0.01 ppm Metallic, Green, Slight Pine
Linalool 0.174 ppm 0.008 ppm Fruity and Floral. Fruit Loops
α-terpineol 0.071 ppm 0.33 ppm Pine β-citronellol 0.016 ppm 0.04 ppm Citrus Floral Geraniol 0.026 ppm 0.004 ppm Floral Citrus
References • Forster, A. The quality chain from hops to hop products. In 48th IHGC Congress, Canterbury, Barth-
Haas Research & Publications (http://www. barthhaas. com); 2001.
• European Brewery Convention Hops and Hop Products, Manual of Good Practice; Getranke - Fachverlag Hans Carl: Nurnberg, Germany, 1997.
• Peacock, V. Fundamentals of Hop Chemistry. Tech. Q.-Master Brew. Assoc. Am. 1998, 35, 4–8.
• Eyres, G.; Dufour, J. Hop Essential Oil: Analysis, Chemical Composition and Odor Characteristics. In Beer in Health and Disease Prevention; Preedy, V. R., Ed.; Academic Press: San Diego, 2009; pp. 239-254.
• Schönberger, C.; Kostelecky, T. 125th Anniversary Review: The Role of Hops in Brewing. J. Inst. Brew 2011, 117, 259–267.
• ASBC Methods of Analysis – Beer Flavor Database http://www.asbcnet.org/MOA/Flavors_Database.aspx (accessed June 15, 2014)
• Kishimoto, T.; Kobayashi, M.; Yako, N.; Iida, A.; Wanikawa, A. Comparison of 4-Mercapto-4-Methylpentan-2-One Contents in Hop Cultivars from Different Growing Regions. J. Agric. Food Chem. 2008, 56, 1051–1057.
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