A Toast to the Chemistry of Noble Grapes · Principles and Practices of Winemaking, Boulton et al.,...
Transcript of A Toast to the Chemistry of Noble Grapes · Principles and Practices of Winemaking, Boulton et al.,...
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A Toast to the Chemistry of Noble Grapes
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ACS WEBINARS™ January 10, 2013
Dr. Susan Ebler
UC Davis Dr. Sara Risch
Popz Europe
A Toast: To the Chemistry Of Noble Grapes
Susan E. Ebeler Department of Viticulture and Enology
University of California, Davis, CA
5 10 15 20 25 30 35 40 45 50 55 60
Winemaking Grape Varieties
Vitis vinifera
Old World/European grapes
Native to Asia Minor, Black and Caspian
Sea area
Photo: http://ngr.ucdavis.edu/aboutus.cfm
Winemaking Grape Varieties
‘Noble Grapes’
V. vinifera varieties historically
considered to make high quality wine
–Sauvignon blanc
–Riesling
–Chardonnay
–Pinot noir
–Cabernet Sauvignon
–Merlot
Chardonnay
Photo: Domaine Chandon
Winemaking Grape Varieties
Numerous cultivars (varieties) of V.
vinifera (> 5000?)
http://www.napavintners.com/wines/napa_valley_terrain_and_terroir.aspx
Winemaking Grape Varieties
Different varieties may give a wine ‘varietal
character’ (flavor, aroma, color, etc.)
Cabernet Sauvignon Sauvignon Blanc Syrah
http://www.napavintners.com/wines/napa_valley_grape_varieties.aspx
Winemaking
Brief Review
– http://acswebinars.org/ebeler
GRAPES
(white or red)
Destem
Crush*
WHOLE MUST
(white or red)
WHITE
JUICE
RED
MUST
Press Pomace
(Skins and
Seeds)
Add Saccharomyces
Ferment
Add Saccharomyces
Ferment
RED
WINE
Secondary microbial
fermentation*
Settle to remove yeast lees
Filter*
Store/age in oak*
Transfer to bottle
Secondary microbial
fermentation*
Settle to remove yeast lees
Filter*
Store/age in oak*
Transfer to bottle
FINISHED
WHITE
WINE
FINISHED
RED
WINE
Press &
Settle Pomace & Lees
(Skins, Seeds,
Yeast) RED
WINE
WHITE
WINE
Winemaking
But wines frequently are not 100% of a single
variety…….
Blending
Blending
Grapes
Variety A
Grapes
Variety B
Grapes
Variety C
Blend
Final Wine
Crush, Ferment Blend
Final Wine
Wine
Variety A
Wine
Variety B
Wine
Variety C
Grapes
Variety A
Grapes
Variety B
Grapes
Variety C
Ferment Ferment Ferment
A varietal designation on a wine label indicates that the
wine contains at least what per cent of the listed grape
variety?
A. 50%
B. 75%
C. 90%
D. 95%
E. 100%
Find information at http://www.ttb.gov
Blending
Why blend?
– Increase flavor complexity
– Maintain consistent character/quality
– Develop winery-typical wines
But…..
– Relationships between chemical composition and
sensory properties of blends?
– Changes in composition and sensory quality of
base wine vs blend?
Wine Blends
Characterizing the chemical and sensory
profiles of US Cabernet Sauvignon wine and
blends
– Hjelmeland, King et al., 2012, Am. J. Enol. Vitic.
doi:10.5344/ajev.2012.12107
Chemical Analysis
Gas chromatography for aroma compounds
Absorbent
coating
Chromatogram
GC Oven
Mass Spectrometer
Hot Inlet
Helium
N. Lloyd, 2010
Chemical (GC) Analysis
61 compounds
– Esters (isoamyl acetate)
– Alcohols (isobutanol)
– Terpenes (linalool)
– Volatile acids (acetic acid)
– Lactones (g-nonalactone)
– Norisoprenoids (b-damascenone, b-ionone)
– Carbonyls (hexanal, diacetyl)
– Etc.
Sensory Analysis
Sensory Analysis
Controlled conditions
(light, temperature, serving
conditions, etc.)
Requires panelist training
Human becomes an
analytical “instrument”
to provide information
about sensory attributes
Sensory Analysis
Appearance, Aroma, Taste sensory
attributes defined and quantified
Use multivariate statistics to relate
chemical and sensory measurements
-0.3
-0.15
0
0.15
0.3
-0.3 -0.15 0 0.15 0.3
Free SO2
Total SO2
Alcohol
Titratable acidity
pH
Residual sugar
Ethyl acetate
Ethyl isobutyrate
Diacetyl
Ethyl butyrate Ethyl-2-methylbutyrate Ethyl isovalerate
Hexanal
Isobutanol
Isoamyl acetate
a-Terpinene
Limonene
Eucalyptol
Isoamyl alcohol
Ethyl hexanoate
r-Cymene
Hexyl acetate
Acetoin
Octanal
Hexanol
(Z)-3-Hexenol
Ethyl octanoate
Cis-linalool oxide
Acetic acid Furfural
Trans-linalool oxide
Camphor
Vitispirane I
Vitispirane II
Linalool
a-Cedrene
5-Methylfurfural
Phenylacetaldehyde
Ethyl decanoate Methionol
b-Citronellol
2-Phenethyl acetate
b-Damascenone
a-Ionone Guaiacol
Benzyl alcohol
Cis-oak lactone
2-Phenethyl alcohol
b-Ionone
Trans-oak lactone 4-Methylguaiacol
g-Nonalactone
4-Ethylguaiacol
2-Ethylphenol
Eugenol
4-Ethylphenol
Syringol Isoeugenol
Farnesol
g-Dodecalactone
Vanillin
MIBP
Overall
aroma
Fresh fruit
Berry
Butterscotch
Wood
Pepper
Vegetal
Barnyard
Overall flavor Sweet
Alcohol
Complexity Sharp
PC1 x-expl 25%, y-expl
35%
PC2 x-expl 13%, y-expl
11%
CS1
CS2
CS3
CS4
CS5
CS6
CS7
CS8
CS10
CS12
CS14 CS15
CS16
CS17 CS18
CS19
CS21
CS22 CS23
CS24 CS13
CS9 CS20
CS11
Multivariate statistical
analysis – PLSR2 using
UnScrambler®
Blending
Relationships between chemical composition and
sensory properties
But…..
Wines not differentiated by region, price, age
(varietal blend)
Changes in composition and sensory quality of
base wines vs blends?
Chemical and Sensory Changes: Base Wines vs Blends
Hopfer et al. 2012
Am. J. Enol. Vitic.63:313-
324;
doi:10.5344/ajev.2012.111
12
Cabernet
Franc
Cabernet
Sauvignon
Merlot
Blend
Final Wine
Wine
Variety A
Wine
Variety B
Wine
Variety C
Grapes
Variety A
Grapes
Variety B
Grapes
Variety C
Ferment Ferment Ferment
Which of the following grape species are
native to North America?
A. Vitis labrusca
B. Vitis rotundifolia
C. Vitis rupestris
D. Vitis vinifera
E. Vitis amurensis
Base Wines vs Blends
Base wines had different sensory and
chemical properties
Chemical composition changed
consistently as ratios of base wines in
blends changed
Base Wines vs Blends
Similar sensory
properties possible
with different blends
Sensory properties
did not change
consistently—
attribute intensities
were enhanced,
suppressed,
averaged—depending
on blending ratio
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
-2
-1
0
1
2
Can 1 38.7 %
Can 2
1
3.8
%
All base wines and the
Cab.Sauv. blends
Can 1 38.7 %
Can 2
1
3.8
%
Base Wines vs Blends
Perceptual
processes in
understanding
aroma/flavor
quality of mixtures
are not well
understood—More
work is
needed……..
-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5
-2
-1
0
1
2
Can 1 38.7 %
Can 2
1
3.8
%
All base wines and the
Cab.Sauv. blends
Can 1 38.7 %
Can 2
1
3.8
%
V. vinifera predominates in winemaking
Numerous V. vinifera cultivars (varieties) used
Blending of varieties is common—influences
flavor, quality, style
Chemical composition and sensory properties
influenced by blending
But, difficult to predict flavor properties of a blend
from composition
Summary
5 10 15 20 25 30 35 40 45 50 55 60
Studying Viticulture & Enology at UCDavis
http://wineserver.ucdavis.edu
B.S. in Viticulture and Enology
M.S. in Viticulture and Enology
PhD in Various Disciplines (Agricultural Chemistry,
Food Science, Microbiology, Plant Biology,
Horticulture, Genetics, Engineering, etc…..)
Certificate in Winemaking for Distance Learners
http://extension.ucdavis.edu/unit/winemaking/certificate/wine
making/
University Extension 1- and 2-Day Shortcourses
http://extension.ucdavis.edu/index.asp
References/Information Sources
Principles and Practices of Winemaking, Boulton et al.,
Chapman & Hall, 1996 (ISBN 0-412-06411-1)
Chemistry of Wine Flavor, Waterhouse & Ebeler, American
Chemical Society, 1998 (ISBN 0-8412-3592-9)
Authentication of Food and Wine, Ebeler et al., American
Chemical Society, 2007 (ISBN 978-08412-3965-4)
Polaskova et al., Chemical Society Reviews, 2008, 37: 2478-
2489, DOI: 10.1039/b714455p
Ebeler and Thorngate, J. Agric. Food Chem., 2009, 57:
8090-8108, DOI: 10.1021/jf9000555
Journal of Agricultural and Food Chemistry
American Journal of Enology and Viticulture
greenrmi.ucdavis.edu rmi.ucdavis.edu
THANK YOU
A Toast to the Chemistry of Noble Grapes
Download the presentation ONE WEEK after webinar:
http://acswebinars.org/noble-grapes
Contact ACS Webinars™ at [email protected]
ACS WEBINARS™ January 10, 2013
Dr. Susan Ebler
UC Davis Dr. Sara Risch
Popz Europe
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From the Lab Bench to the Kitchen Bench
Mr. Bill Courtney, Cheese-ology
Ms. Iryna King, Rubicon Genomics
Thursday, January 24, 2013
Ignorance:
Why Science Shouldn’t Start with a Hypothesis
Dr. Stuart Firestein, Columbia University
Dr. Darren Griffin, University of Kent
Contact ACS Webinars™ at [email protected]
39
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Riedel Decanter
40
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Oster Wine Chiller & Opener
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