Wine Flavor Chemistry

Flavor is the psychological interpretation of the physiological response to a physical stimulus

Milton Bailey, University of Missouri, 1986

2 -methoxy 3 isobutyl pyrazine (2 ppt)

Identified in Bell Peppers (1969)

Sensitive to light (1986)

Method for quantifying : (2003)

0

9 0

1 8 0

2 7 0

0 11 22 33 44

12

13

BerryAroma

BerryFlavor

VANILLABUTTERSCOTCH

MINT

CLOVE

SOY

Bell PepperAroma

VegyFlavor

BellPepper

Sites

Wines from two vineyard sites

WHAT CAUSES VEGY FLAVOR in WINE?

SENSORY PCA – 19 wines (1986)

Clove

Mint

BerryF

BerryF

Vanilla

ButterscotchBellPepper

VegyF

Vegy

Soy

SpicyF

-3

-2

-1

0

1

2

3

4

5

6

-6 -4 -2 0 2 4 6

PC1(42.2%)P

C2(2

8.7

%)

SOIL PCA

CEC

OMRootDepth

HardenpH

Texture

SoilAge

C:F %Gravel

Structure

Wt Fines

-4

-3

-2

-1

0

1

2

3

4

-4 -3 -2 -1 0 1 2 3 4

PC1 (26.4%)P

C2 (24.2

%)

PLS of Soil and Vineyard factors versus Sensory

Noble and Elliot-Fiske, 1990

Soy

VegyVegyF

BellPepper BerryF

Berry

Butterscotch

VanillaMint

Clove

SpicyF

%Clay

SoilpH Structure

H20HoldingCap.

Year(younger)

SoilAge(older)

VineAge

Rootstock

WarmerClimate %Gravel

SoilinRootZone

-4

-2

0

2

4

6

8

-6 -4 -2 0 2 4 6

BandAid

Spicy

Fruit by mouth

Berry

Vanilla

Eucalyptus

Green Bean

Soy

Vegetative by mouth

Black Pepper

Bell Pepper

PC1(39%)

PC

2(3

0%

)

Heymann (1986) Descriptive Analysis of Cabernet sauvignon

Earthy

Vegetative

Body

Chemical

Animal

Vanilla

Spicy

AcidityBerry

Floral

AstringencyColor-

Intensity

Color-Hue

PC1(39%)

PC

2(3

1%

)

Sivertsen, et al.(1999). Classification of French red wines according to geographical origin by of multivariate data analyses

passionfruit

persistenceart. fruit

citrus grapefruit

nutty

grassy

licorice

bodyfloral

37%

25%

Fischer, et al. (1999) The impact of geographic origin, vintage and wine estate on sensory properties of Vitis vinifera cv. Riesling

Eucalyptus

Fresh Mint

Musty

Canned Veg

Bell Pepper

Cedar

Ethanol

Fresh Berry

CherryBlk Cherry

Karen Hein, 2005

BP-B

BP-R

BP-S

Bell-Pepper

Bell Pepper1

Corn

C-B C-R

C-S

Corn1

MintM-B

M-R

M-S

BaseBerry

Raspberry

Strawberry

CANONICAL VARIATE ANALYSIS OF SPIKED WINE SAMPLES

Morrison and Noble, 1990. Am. J. Enol. Vitic.41: 193 - 200.

Cabernet sauvignon – differences too subtle to describe

0123456

Vegetal

Black Pepper

Rose

Chocolate

Berry

Fruit by Mouth

Astringent

Veg by Mouth

12 UP 12 LO 25B UP 25B LNE 25B LSW

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

25 LNE 25B LSW 25B UP 12 LO 12 UP

Fra

ctio

n A

vail

ab

le L

igh

t

0

5

10

15

20

25

30

35

40

25LNE

25BLSW

25BUP

12 LO 12 UP

M Iso B

Pyra

zin

e (

pp

t)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

25 LNE 25BLSW

25B UP 12 LO 12 UP

Vig

or

(Pru

nin

g Y

ield

)Fraction Light Vigor

Pyrazine

0

1

2

3

4

5

6

7

25B LNE 25BLSW

12 LO 25B UP 12 UP

Inte

nsi

ty B

ell P

ep

per

Bell Pepper Aroma

Vegy Saga

Buds/Vine

10 15 20 25 30 35 40 45 50

MIB

P (n

g/L)

-5

0

5

10

15

20

20002001

R2=0.7385***

R2=0.7007***

IBMP (ng/L)

0 2 4 6 8 10 12 14 16 18 20

Ave

rage

Inte

nsity

Rat

ing

0

2

4

6

8

R2=0.5720***

R2=0.3541*

MIBP (ng/L)

0 2 4 6 8 10 12 14 16 18 20

Ave

rage

Inte

nsity

Rat

ing

2

4

6

8

20002001

A) Bell Pepper Aroma

IBMP (ng/L)

0 2 4 6 8 10 12 14 16 18 20

Ave

rage

Inte

nsity

Rat

ing

0

2

4

6

8 B) Vegetative Aroma

R2=0.5064**

R2=0.2091 (0.1)

R2=3702*

C) Vegetative Flavor by Mouth

R2=0.6394***

Pruning: Pruning affects yield much more than pruning weight. Pruning to more buds/vine generally increases yield and decreases shoot length. Pruning to higher yield can lead to delayed sugar accumulation (probably when leaf area / fruit weight gets below 12 cm2 / gm), and at even higher yields decreased color in fruit, and in extreme cases decreased budbreak and fruitfulness the following year. Pruning to two times the standard crop load in Napa (4-bud spurs instead of 2-bud spurs) did not prevent ripening. Pruning to higher yields resulted in less veggy, less astringent, and more fruity attributes in Cabernet Sauvignon wines. And the veggy and astringent attributes were correlated with the concentration of MIBP (methoxypyrazine) and tannins in the wines. There were almost no significant differences in sensory attributes among wines made from vines with different cluster thinning treatments.

Evaluation of 96 Bordeaux red wines

IBMP is the contributor to vegetal aroma in Cabernet sauvignon; Cabernet franc and Sauvignon blanc

Compound only found in a minority of Merlot

Compounds released in white wines

4-mercapto-4-methylpentan-2-one (4MMP) (also in Scheurebe) 0.8 ng/l*; range 0-40 -- box tree, broom flower; cat pee; conifer4-mercapto-4-methylpentan-2-ol (4MMPOH) 55 ng/l*; range 0-150 --

citrus zest; grapefruit3-mercapto-3-methylbutan-1-ol (3MMB) 1,500 ng/l*; range 30-150 – cooked

leeks 3-mercaptohexan-1-ol (3MH) 60 ng/l*; range 200-5,000 – grapefruit;

passion fruit; passion fruit skin3-mercaptohexylacetate (3MHA) (also in Merlot, Cabernet sauvignon) 4.2

ng/l*; range 0-500 – box tree; passion fruit; sweet sweaty

Aqueous 12% alcohol solution with 5g/l tartaric acid; pH 3.5 25 J, triangle; 50% correct

increases during fermentation as these potent thiols released from their S-cysteine conjugate precursors

Markers for great Sauvignon blancMarkers for great Sauvignon blanc

Thiols in other varieties

4MMP and A3MH (3-mercaptohexylacetate [box tree]): Impact on aromas of Colombard and Muscat d’Alsace wines As well as on young wines from Petit manseng*

3MH Contributes passion fruit and grapefruit to Gewurtztraminer,

Riesling, Petit manseng and botrytized Semillon

*White variety, South West France – may be Albarino: floral fruity flavors, a distinct lemon and fruit salad flavor & high acidity increasing popularity in Languedoc & California

Tominaga et al. (2000) AJEV 51(2):178-182

Production, location and extraction of S-Cysteine Conjugates

Moderate water stress favor S-cysteine conjugate (P-thiol) formation; severe prolonged stress limits production

Location of P-thiolsdiffer as f(volatile thiol) P-4MMP and P-4MMPOH -- 80% in juice P-3MH – 50:50 between juice and skin

Upto 19 hours skin contact Some ↑ in P-4MMP and P-4MMPOH (20% + 30%) 50% ↑ in P-3MH (even more extracted if skin contact at

18C vs 10C)

Peyrot des Gachons, Catherine: Aroma Potential of Sauvignon blanc grapes, PhD Dissertation Bordeaux

Transformation of p-thiols into varietal aromas

Transformation % low (1 month after fermentation) – due to yeast lyases 1.4% for P-4MMP; 3% for P-4MMPOH; 4.2% for P-3MH

Not much transformed? Or Lost? Or metabolized or unstable? – do not yet know

Do know that P-thiol disappearance is correlated with thiol appearance

Peyrot des Gachons, Catherine: Aroma Potential of Sauvignon blanc grapes, PhD Dissertation Bordeaux

Norisoprenoids/norterpenoids from carotenes Beta-damascenone Shiraz stalky, earthy, cigar, and tobacco aromas

black pepper aroma by GCO not id’d

Cabernet Sauvignon and Merlot dried fig, tobacco and chocolate aromas

Zinfandel Preliminary studies: Not much contribution

Glycosides in Red varieties

floral

apple

honeyhoney

chocolatechocolate dried figdried fig

tobaccotobacco

Base wine

Napa Cabernet juiceglycoside hydrolysate

0

1

2

3

4

Juice glycoside hydrolysate

n=14 judges x 2 reps

floral apple

honey

chocolatechocolate

dried figdried fig

tobaccotobacco Base wine

Napa Cabernet skinNapa Cabernet skinglycoside hydrolysateglycoside hydrolysate

Napa Cabernet skinNapa Cabernet skinglycoside hydrolysateglycoside hydrolysate

0

1

2

3

4

Skin glycoside hydrolysate

PLS of Aroma attributes versus volatiles

floral

apple

honey

dried fig

chocolate

tobacco

volatiles

juices

skin extracts

Component 1

Component 2

Volatiles related to the honey attribute

Norisoprenoids:•damascenone•hydroxydamascone

•dehydro ß ionone•TDN•vitispirane•actinidol

Benzene derivatives:•vanillin•acetovanillone•cinnamic acid

Monoterpenes:•ocimenol•furan linalool oxide •an ene diol

Others:•acetyl furan •ethyl decanoate•diethyl propanedioate

PLS of Aroma attributes versus volatiles

floral

apple

honey

volatiles

juices

skin extracts

Component 1

Component 2

dried fig

chocolate

tobacco

Volatiles associated with dried fig/tobacco

Benzene derivatives:•syringic acid•ethyl syringate•a methoxy phenol

Monoterpenes:•trimethyl vinyltetrahydropyran•furan linalool oxide

Others:•two unknowns•heptanoic acid•hexadecanoic acid•2-Et-3-Me maleic anhydride

Trellising or leaf removal increases light

< 2-methoxy 3 isobutyl pyrazine

> norisoprenoids

Maturity

How to assess pH, TA, °B?

Grape Must Evaluation (evaluate in < 1 hour)Rinse and Crush grapes, add 20 ppm SO2

Homogenize skins/juice versus juice

Grape Berry Evaluation

Vineyard Variables:

Temperature:

Cool: retain more volatilesWarmer: more esters but lose more (fruity)

low MW

Yeast strain:? Biggest issue is H2S production

“Natural” versus inoculation

Skin Contact Time/Cap Management

Increase K, pH, phenols, anthocyanins

Centrifuging?

FERMENTATION

Terpene glycosides hydrolyze, but terpenes interconvert to less fruity forms

Vitaspirane and 1,1,6 trimethyl 1,2 dihydronaphthalene

increase

Esters hydrolyze slowly: Acetate esters & higher MW faster.

Acids esterify; pH; Tannins polymerize

Oxidation reactions

AGING

Extraction of volatiles: vanillin, eugenol, oak lactone

Extraction: phenols, acids, lignins, CHO

Oak Aging

Oak aging continuedVARIABLES:

Source oak (Am Vanillin; Fr Phenols, extract)

Sawn vs split

Air vs kiln drying Air Vanillin; Kiln HMF

Air drying in cool vs hot area

Hot Vanillin ,Oak lactone

Hot vanilla, caramel, buttery

Steamed or bent over fire

Degree toasting Furfural, Vanillin