How do cultural practices impact wine aroma and flavor? Nick Dokoozlian E&J Gallo Winery

and wine flavor in the vineyard? How do we manage grape and wine flavor in the vineyard? Outline Measuring quality and flavor development Practices influencing flavor development Harvest date Crop load Late season water status Trellis Clonal selection Summary

Measuring grape quality Aroma Taste Color Mouthfeel Flavor = aroma x taste

How do we manage grape and wine flavor in the vineyard? Harvest Date

Cabernet Sauvignon grapes at harvest in California Mean soluble solids of Cabernet Sauvignon grapes at harvest in California

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Berry maturity metrics

Berry Sensory

Berry Sensory Berry sensory trends Trained tasters can consistently distinguish several different flavor or aroma buckets during ripening Significant sensory trends are apparent during the later stages of ripening (>20 oBrix)

Sensory “flavor buckets” in grape berries near harvest Responsible compounds Category Negative Veggie Methoxypyrazine C6 compounds Positive Green fruit Fresh fruit Cooked or jammy fruit Glycosylated bound precursors, acid esters and thiols Ex: norisoprenoids

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? Sugar-based harvest

? Sugar-based harvest Sensory-based harvest

Berry to Wine Sensory

Linking berry and wine sensory Berry sensory is subjective and not high- throughput Can we use chemistry to describe our major aromas buckets? Vegetable Green fruit Fresh fruit Jammy fruit Are chemical finger prints for each bucket possible ?

Grape aromas & aroma precursors Methoxypyrazine Veggie aroma Free volatile aromas Alcohols, aldehydes, terpenoids, norisoprenoids Glucose glycosides Flavor precursors bound to sugars Fatty acid esters Acid esters (fresh fruity notes in all cultivars) Thiols Sulfur based precursors in grapes ( ex. cysteine) - tropical notes in Sauvignon blanc, other cultivars

Sensory “flavor buckets” in grape berries near harvest Responsible compounds Category Negative Veggie Methoxypyrazine C6 compounds Positive Green fruit Fresh fruit Cooked or jammy fruit Glycosylated bound precursors, acid esters and thiols Ex: norisoprenoids

Jammy fruit aromas Compound Aroma Benzyl alcohol (ppb) Phenethyl alcohol (ppb) Geraniol (ppb) B-ionone (ppb) Terpinene (ppb) Linalool (ppb) Eucalyptol (ppb) B-damasecenone (ppb) Red berry Roses Citric Prune Citrus Flowery, lavender Eucalyptus Rose wood

The Odor Activity Value (OAV) Concentration of target compound in grape Known sensory detection threshold in water Example: 4000 ppt OAV= = 40 100 ppt

Cabernet Sauvignon Veggie Chemistry Aroma activity value

Cabernet Sauvignon Green fruit Aroma activity value

Cabernet Sauvignon Jammy fruit Aroma activity value

Managing wine flavor & alcohol in the vineyard How do we synchronize berry sugar and flavor accumulation ?

Changes in berry sensory over time 2004 2004 Rapid sugar accumulation due to low crop load Delayed flavor development due to environment, ripening rate

Changes in berry sensory over time Slow sugar accumulation due to large crop load 2005

Crop Load or Vine Balance How do we manage grape and wine flavor in the vineyard? Crop Load or Vine Balance

Yield to pruning weight ratio integrates vine capacity and yield Crop Load Yield to pruning weight ratio integrates vine capacity and yield Canopy size Fruit yield Accounts for differences in vineyard design, plant density, vine vigor and site capacity

Vine balance and ripening rate Expected ripening rate Vine yield Pruning weight Expected ripening rate < 4 5 – 8 > 10 Too little crop = rapid Balanced = optimum Too much crop = slow

Cabernet Sauvignon Under-cropped vines Yield = 4 tons per hectare Yield pruning weight ratio = 3 Over - cropped vines Yield = 30 tons per hectare Yield pruning weight ratio = 14 Balance - cropped vines Yield = 15 tons per hectare Yield pruning weight ratio = 8

Cabernet Sauvignon Under-cropped vines Yield = 4 tons per hectare Yield pruning weight ratio = 3 Over - cropped vines Yield = 30 tons per hectare Yield pruning weight ratio = 14 Balance - cropped vines Yield = 15 tons per hectare Yield pruning weight ratio = 8

Balanced Cropped = 8:1 Under Cropped = 3:1 Over Cropped = 14:1

Ratio of dark fruit to green aromas Balanced-cropped 8:1 TT Threshold Under-cropped 3:1 Ratio of dark fruit to green aromas Over-cropped 14:1

Under cropped Over cropped

affect berry aroma at maturity ? How does ripening rate affect berry aroma at maturity ? High LA:FW (Under cropped) How important is D sugar to: time Low LA:FA (Over cropped) Fruit aroma accumulation? Green aroma degradation? Sugar accumulation rate (oBrix) Flavor accumulation Rate? Veraison Harvest Berry ripening (time)

Late Season Water Stress How do we manage grape and wine flavor in the vineyard? Late Season Water Stress

Begin treatment at 21 Brix Ramp-up irrigation = 100% ETc Control irrigation = 70% ETc Ramp-up Begin ramp-up Control Begin treatment at 21 Brix

Vine response to irrigation levels during the final stages of ripening Cabernet Sauvignon - Lodi Treatment Soluble solids at harvest (Brix) Berry Color (mg/g) IBMP (ppt) Bound aroma precursors Standard 26.7a 1.2 a 2.1 a 50,560 b Ramp-up 24.5 b 1.1 a 1.4 a 59,860 a From: Prichard et al 2005

Trellis Design and Canopy Efficiency How do we manage grape and wine flavor in the vineyard? Trellis Design and Canopy Efficiency

75% Exposed LA 45% Exposed LA 35% Exposed LA 65% Exposed LA

From Kliewer and Dokoozlian - 2000

Back to basics - performance metrics Indices Measure Fruit yield Production efficiency Canopy efficiency Fruit microclimate Pruning weight Exposed leaf area Total leaf area Exposed clusters Total clusters

Clonal Selection How do we manage grape and wine flavor in the vineyard? Clonal Selection

Merlot Clones – 2009 Vintage All clones adjusted to similar crop loads (~7:1) following berry set

Summary Maturity measures are changing from sugar-based metrics to flavor-based metrics Berry sensory and analytical tools can monitor berry flavor profiles Vine balance (ratio of yield to pruning weight) is critical to fruit ripening rate and flavor development Synchronizing sugar and flavor accumulation Greater focus on the impact of other vineyard practices on flavor development is needed

Acknowledgements David Vasquez, Luis Sanchez, Marin Mendez, Jim O’Donnell and Nona Ebisuda Mike Cleary, Beth Wilson and Lee Raley Laure David, Jim Kolsky and Lyndsay Noble Cyd Yonker and Tom Pugh Alan Reynolds and Jim Collins