Transcript VEN124 Section I

VEN124 Section I
Wine Production Begins in the
Vineyard
Lecture 1:
Factors Influencing Wine Composition
and Quality
Good wine cannot be made from
bad grapes . . .
Wine quality is dependent upon
viticultural practices and
decisions.
The Definition of Wine Quality
Quality Is Subjective
• Is it “quality” or “preference”?
• Can a subjective standard be
objectively assessed?
• Is “quality” truly definable?
Quality is dependent upon
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Preference
Perception
Experience
Expectations
The Many “Definitions” of Quality
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Commercial Acceptability
Nearness to a Specific Target
Complexity
Inharmonious Notes
Quality as Commercial Acceptability
The Absence of Defects:
For that style
For any style
Quality as Commercial Acceptability
• Defects/Taint compounds well defined
• Trained tasters
• “Statistically tested” tasters
– Reproducibility
– Threshold of detection
– Matrix effects
Targeted Definitions of Wine Quality
• An ideal wine exists
• A consensus of the ideal characters
exists
• Quality is determined by closeness to
the ideal
• For regional typicity, the judgment of
nearness to target may rest with a
government body of tasters
Targeted Definitions of Wine Quality
• Regional typicity: “terroir”
• Varietal typicity
• True-to-style
– Common commercial style
– Winery-specific style
Targeted Definitions of Wine Quality
• Nearness to target is a subjective
assessment
• Challenging to use humans as an
objective analytical tool
• Dependent upon genetic factors
• Dependent upon physiological and
psychological factors
Complexity as Quality
• Linear complexity: Wines have multiple
intense aromas and flavors that are “forward”:
immediately apparent upon smelling/tasting
the wine
• Vertical complexity: As wines “breathe” in
glass the aroma/flavor profile changes
dramatically, positively and continually
• Both aim for “harmony”: melding of flavors
and aromas
Complexity as Quality
• Assessment of complexity is subjective
– When is the wine complex enough?
– What is “harmonious”?
– When is a wine not harmonious?
• Dependent upon style/varietal
• Dependent upon
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Preference
Perception
Experience
Expectations
Off-Notes as Index of Quality
• Some believe that a wine free of offnotes is “too clean”
• Off-notes lend character to a wine
• Alternately, off-notes accompany
microbial activity and therefore track
with greater microbially-derived
complexity
• Harmonious complexity “boring”
Off-Notes as Index of Quality
• Very subjective
• When does “Off” become
unacceptable?
• Is this the absence of a standard of
acceptability?
Who Controls Definition of Quality?
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Government
Producers
Consumers
Intermediaries (Wine Critics/ Wine
Writers/Distributors/Marketers)
Terroir versus AVA
Terroir
Terroir, a term coined by the French,
refers to the influence of non-climatic
environmental factors1 (soil, topography)
on wine composition and quality
1Ribereau-Gayon,
P., et al. Handbook of Enology,
Vol 1: The microbiology of wine and vinifications.
John Wiley and Sons, Ltd. (2000).
Terroir
Has many interpretations . . . Some
include climate in discussions of
terroir others also include the “human
element”
Terroir
• Terroir characters are defined by the traits of
the wines following elimination of other
variables, not from direct demonstration of
the influence of environment on those
characters
• Recipes for both vineyard and winery
procedures are legislated, minimizing the
impact of these decisions on wine
composition across vintages
• Used in marketing to assure consistency of
product for the consumer
American Viticultural Areas (AVA)
AVA status requires demonstration of
some uniqueness of a specific
geographic wine producing region
AVA
• No restrictions on vineyard or winery
practices; uniqueness of wine expected
independently of “recipe”
• Allows considerable variation in
composition of wine while retaining a
regional “signature”
Wine and Grape Composition
Wine Characters Derive from One of
Four Sources:
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Grape
Activity of microorganisms
Processing decisions
Aging
GRAPES
PROCESSING
MICROBES
AGING
Certain styles emphasize
contribution of one sector over
others, but all will make a
contribution to the wine
Grape
Microbe
Processing
Aging
Microbe
Grape
Processing
Aging
Grape Composition Influenced by:
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Variety
Clone
Rootstock
Soil
Canopy
management
• Terrain
• Pest Pressure
• Disease Pressure
• Climate
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Rainfall
Humidity
Sunshine
Wind speed
• Cluster microclimate
• Seasonal Variation
• Vineyard Practices
Microbial Contributors to Wine
Characters:
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Saccharomyces
Lactic Acid Bacteria
Grape Flora
Winery Flora
Inocula
Processing Decisions Impacting
Wine Characters:
• Harvesting
conditions
• Maceration
decisions
• Extraction
conditions
• Additions to
juice/must
• Fermentation
conditions
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Lees contact
Clarification
Filtration
Fining
Blending
Stabilization
Treatments
Aging Decisions Impacting Wine
Characters:
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Time
Temperature
Cooperage
pH
Wine composition
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Evaporation
Agitation
Oxygen exposure
Lees exposure
Sanitation practices
Bad wine can be made from
good grapes . . .
Wine quality is also dependent
upon enological practices and
decisions