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

• Preference

• Perception

• Experience

• Expectations

The Many “Definitions” of Quality

• 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

– Preference – Perception – Experience – Expectations

Off-Notes as Index of Quality

• Some believe that a wine free of off-notes 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?

• 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:

• Grape

• Activity of microorganisms

• Processing decisions

• Aging

GRAPES MICROBES

AGINGPROCESSING

Certain styles emphasize contribution of one sector over others, but all will make a contribution to the wine

Grape

Microbe

AgingProcessing

GrapeMicrobe

Aging

Processing

Grape Composition Influenced by:• Variety• Clone• Rootstock• Soil• Canopy

management• Terrain • Pest Pressure• Disease Pressure

• Climate– Rainfall– Humidity– Sunshine– Wind speed

• Cluster microclimate• Seasonal Variation• Vineyard Practices

Microbial Contributors to Wine Characters:

• 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

• Lees contact• Clarification• Filtration• Fining• Blending• Stabilization

Treatments

Aging Decisions Impacting Wine Characters:

• Time• Temperature• Cooperage• pH• Wine composition

• 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