5/19/2017

Managing green aromas in the vineyard Outline • Background and business need –a viticulture perspective • Berry ripening and green aromas –sensory to chemistry • Evolution of green aroma measures and metrics • Impact of environment and growing conditions on green aromas • Physiological regulation of green aroma compounds • Summary

Consumers drive changes in wine style: The flavor evolution of the late 1990’s

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Changes in berry sensory attributes during fruit ripening 4 Cabernet Sauvignon 2005

Fruit 3 Characteristics

2

1 Vegetative Characteristics

Flavor intensity via sensory 0

18 19 20 21 22 23 24 25 26 27 28 29 30 31

o Soluble solids ( Brix) 3

5 Cabernet Sauvignon

4 Fruit ? Characteristics 3

2 Vegetative Characteristics 1 Flavor intensity via sensory 0

18 19 20 21 22 23 24 25 26 27 28 29 Soluble solids (oBrix)

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5 Cabernet Sauvignon

4 Fruit ? Characteristics 3 Sugar-based Sensory-based harvest harvest 2 Vegetative Characteristics 1 Flavor intensity via sensory 0

18 19 20 21 22 23 24 25 26 27 28 29 Soluble solids (oBrix)

Evolution of berry maturity metrics

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Vegetative aromas in grapes IBMP and C6 compounds Compound Aroma

Methoxypyrazine (ppb) Bell pepper t-2-hexenal (ppb) Green Hexenol (ppb) Green, grass t-3-hexenol (ppb) Green c-3-hexenol (ppb) Freshly cut grass t-2-hexenol (ppb) Fresh green, nutty Hexanal (ppb) Hay Hexadienal (ppb) Green 7

Vegetative or Green Aroma

2-Methoxy-3-Isobutylpyrazine Methoxypyrazine IBMP 8

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Vegetative or Green Aroma

IBMP sensory thresholds Grapes 3.0 ppt

Wine 7.0 ppt

2-Methoxy-3-Isobutylpyrazine Methoxypyrazine IBMP 9

Vegetative aromas

3.0 Cabernet Sauvignon 2004 2.5 Reaches

2.0 2 minimum Peaks r = 0.9689 concentration shortly after near end of 1.5 veraison Degrades season during 1.0 ripening

0.5 Methoxypyrazine (ppt)

0.0 16 18 20 22 24 26 28 30 o Soluble solids ( Brix) 10

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Cabernet Sauvignon Linking berry sensory to chemistry 5 120 VeggieVeggie flavor in grapes

4 100

80 3 Chemistry 60 2

40 1 20

Sensory rating(1-5) Sensory

0 Aroma compound index 0 18 20 22 24 26 Soluble solids (oBrix)

Berry to Wine Sensory 3.0

2.5

2.0 Jammy fruit in wine 1.5 Jammy fruit Vegetative in grapes aroma in wine 1.0

Vegetative 0.5 aroma in grapes

Aroma intensityvia sensory 0.0

22 23 24 25 26 27 28 29 Soluble solids (oBrix)

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5 Cabernet Sauvignon

4 Fruit ? Characteristics 3

2 Vegetative Characteristics 1 Flavor intensity via sensory 0

18 19 20 21 22 23 24 25 26 27 28 29 Soluble solids (oBrix)

25 AverageMean sugar Brix levels at harvest of Cabernet Sauvignon (allat harvest red varieties in California) Source: CA Grape Crush Report 24

23

22 Souble solids (Brix) 21

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Year

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Cabernet Sauvignon - Sonoma

30

25 2005 IBMP levels at harvest vary 2004 significantly among 20 seasons – even in a single vineyard 15 block

2006 10

Methoxypyrazine (ppt) Methoxypyrazine 5

0 14 16 18 20 22 24 26 28 30 o Soluble solids ( Brix) 15

Managing green aromas in the vineyard

5 Cabernet Sauvignon

4 Fruit How do we Characteristics 3 synchronize flavor 2 Vegetative accumulation Characteristics 1 and green aroma degradation? Flavor intensity via sensory via intensity Flavor 0

18 19 20 21 22 23 24 25 26 27 28 29 Soluble solids (oBrix)

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Crop Load Yield to pruning weight ratio integrates vine

Canopy size Fruit yield

Accounts for differences in vineyard design, plant density, vine vigor and site capacity

Cabernet Sauvignon 32 Under-cropped vines 30 Yield = 1.8 tons per acre Yield:pruning weigh ratio = 3 28

26

24

Over - cropped vines 22 Yield = 12.1 tons per acre Yield:pruning weigh ratio = 14 20 Soluble solids (Brix) Balance - cropped vines 18 Yield = 5.8 tons per acre Yield:pruning weigh ratio = 7 16 1 8 15 22 29 6 13 20 27 3 10 September October November Time

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Cabernet Sauvignon 32 Under-cropped vines 30 Yield = 1.8 tons per acre Yield pruning weigh ratio = 3

28

26 X X X

24

Over - cropped vines 22 Yield = 12.1 tons per acre Yield pruning weigh ratio = 14 20 Soluble solids (Brix) Balance - cropped vines 18 Yield = 5.8 tons per acre Yield pruning weigh ratio = 7 16 1 8 15 22 29 6 13 20 27 3 10 September October November Time

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How does ripening rate affect berry aroma at maturity? How important is sugar to:

• Fruit aroma accumulation? • Green aroma degradation?

VeraisonBerry ripening (time) Harvest

Veraison Merlot

IBMP (ppt) <5 5-10 11-20 21-40 41-80 >80

IBMP Regional analyses 2007 – 2011

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Key findings – regional analysis IBMP concentrations in grapes at harvest were highly correlated with several key vineyard parameters ◦ Soil moisture level at bud break ◦ Canopy size at veraison C6 concentrations in grapes at harvest were highly correlated with regional weather trends ◦ C6 compounds increased during prolonged period of cool temperatures – particularly near harvest ◦ Not correlated with vineyard parameters Models provided conflicting perspectives compared to widely accepted dogma ◦ IBMP was generally greatest in the warmest regions, and lowest in the coolest regions

What are the key vineyard factors or physiological parameters regulating IBMP production? – Direct effects? – Indirect effects?

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Cabernet Sauvignon

Impact of vine vigor? Impact of fruit shading?

Merlot

*Treated vines grown without rainfall during the Control winter, then irrigated normally Rainfall exclusion *Fruit zone light Rainfall environment was exclusion similar for both Berry IBMP (ppt) treatments

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Wine Sensory - Merlot

Rainfall exclusion Control

Shoot growth rate and IBMP*

*Fruit zone light environment was similar for both treatments

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Influence of berry growth rate on IBMP levels near veraison

0.5

0.4

0.3 Berry IBMP 0.2 ~150 ppt (mm/berry/week) Berry

Relative berry grown rate IBMP 0.1 ~15 ppt

5/17 6/1 6/14 6/28 7/12

Date

Vegetative aromas

5 Degradation rate very sensitive to 4 temperature & light Shaded 3 r2 = 0.9979

Exposed 2 r2 = 0.9635

1 Methoxypyrazine (ppt) Methoxypyrazine

0 18 19 20 21 22 23 24 25 26 o Soluble solids ( Brix) 30

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Influence of basal leaf removal timing on IBMP levels at harvest - Cabernet Sauvignon Basal leaf IBMP at harvest Location removal timing (ppt) Control 10.2 a* Fruit set 2.5 b Madera Veraison 2.0 b (warmest) Veraison + 3 wks 2.7 b Control 8.2 a* Fruit set 1.5 c Lodi Veraison 2.0 c Veraison + 3 wks 4.3 b Control 6.0 a* Healdsburg Fruit set 1.8 b (coolest) Veraison 2.8 b Veraison + 3 wks 5.7 a

Influence of basal leaf removal timing on IBMP levels at harvest - Cabernet Sauvignon Basal leaf IBMP at harvest Irrigation level removal timing (ppt) Control 24.5 a* Fruit set 8.7 c 100% ETc Veraison 7.3 c Veraison + 3 wks 15.9 b Control 12.3 a* Fruit set 2.5 c 70% ETc Veraison 2.0 c Veraison + 3 wks 4.3 b Control 2.1 a* Fruit set 0.7 c 50% ETc Veraison 0.8 c Veraison + 3 wks 1.4 b

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OMT3 Gene Expression

100

75

50 Leaf removal 25 performed

0 Fruit Veraison Set Gene expression value (RPKM) Gene expression 0 7 14 21 28 35 42 49

Days after full bloom

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Managing green aromas in the vineyard • Strong relationships among several vineyard parameters and fruit IBMP levels have been reported  Think about factors that impact vine capacity

• Manage early – regulation of key physiological pathways occurs very early (pre‐bloom?) in berry development  Irrigation, leaf removal, N fertilization

• Need to understand direct and indirect effects of vineyard parameters on IBMP accumulation  Ex: Fruit zone light microclimate vs. vigor

• Need to characterize IBMP synthesis and degredation kinetics in the vineyard  Optimize cultural practices

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