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How do cultural practices impact wine aroma and flavor?. Nick Dokoozlian E&J Gallo Winery. 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
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How do cultural practices impact wine aroma and flavor? Nick Dokoozlian E&J Gallo Winery
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
Mean soluble solids of Cabernet Sauvignon grapes at harvest in California
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 Sensory buckets Responsible compounds Category Negative Methoxypyrazine C6 compounds Veggie Positive Glycosylated bound precursors, acid esters and thiols Ex: norisoprenoids Green fruit Fresh fruit Cooked or jammy fruit
? Sugar-based harvest
? Sugar-based harvest Sensory-based harvest
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 Sensory buckets Responsible compounds Category Negative Methoxypyrazine C6 compounds Veggie Positive Glycosylated bound precursors, acid esters and thiols Ex: norisoprenoids Green fruit Fresh fruit Cooked or jammy fruit
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 OAV= 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
How do we manage grape and wine flavor in the vineyard? Crop Load or Vine Balance
Canopy size Fruit yield Crop Load Yield to pruning weight ratio integrates vine capacity and yield Accounts for differences in vineyard design, plant density, vine vigor and site capacity
Vine balance and 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
Balanced-cropped 8:1 TT Threshold Under-cropped 3:1 Ratio of dark fruit to green aromas Over-cropped 14:1
Over cropped Under cropped
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)
How do we manage grape and wine flavor in the vineyard? Late Season Water Stress
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 From: Prichard et al 2005
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
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
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