A Toast to the Chemistry of Noble Grapes · Principles and Practices of Winemaking, Boulton et al., Chapman & Hall, 1996 (ISBN 0-412-06411-1) Chemistry of Wine Flavor, Waterhouse

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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


‘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


Numerous cultivars (varieties) of V.

vinifera (> 5000?)

http://www.napavintners.com/wines/napa_valley_terrain_and_terroir.aspx


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


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

%


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

http://wineserver.ucdavis.edu

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:



ACS WEBINARS™ January 10, 2013

Dr. Susan Ebler

UC Davis Dr. Sara Risch

Popz Europe

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Alternative Careers:

From the Lab Bench to the Kitchen Bench

Mr. Bill Courtney, Cheese-ology

Ms. Iryna King, Rubicon Genomics


Ignorance:

Why Science Shouldn’t Start with a Hypothesis

Dr. Stuart Firestein, Columbia University

Dr. Darren Griffin, University of Kent


39

And the Winner Is!!!

Riedel Decanter

http://www.acswebinars.org/


40

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Simply let us know:

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Oster Wine Chiller & Opener

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A Toast to the Chemistry of Noble Grapes · Principles and Practices of Winemaking, Boulton et al., Chapman & Hall, 1996 (ISBN 0-412-06411-1) Chemistry of Wine Flavor, Waterhouse

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