Viticulture Flashcards
What is Viticulture?
The study/art of grape growing
What decisions do the grower/viticulturist face?
Vine training & pruning methods Canopy management Fertilization & irrigation Harvest dates Disease control Monitoring the development of the vineyard
What do advances in viticulture aim to do?
Reduce the vagaries of weather and disease and promote either the quantity or quality of wine.
List the stages of the life cycle of the vine in order
Weeping Budbreak Flowering Fruit Set Veraison/Cane Ripening Ripe Harvest/Vendange
What is weeping or bleeding?
The first stage of the life cycle of the vine. Watery sap will leak from the pruned canes.
At what average air temperature does the vine emerge from dormancy?
50 degrees F
What is budbreak?
The second stage of the life cycle of the vine. The first small shoots and leaves will break through buds left intact by winter pruning.
What is the vine vulnerable to during budbreak?
Frost
What are embryo clusters?
Small green clusters that form on the shoots by mid-April
When does budbreak occur?
March or April
When does weeping/bleeding occur?
February
When does flowering occur?
6 to 13 weeks after initial budbreak, depending on the climate
What is flowering?
Third stage of the life cycle of the vine. Embryo bunches bloom into small flowers for about ten days, and the self-pollinating grapevine begins the process of fertilization.
What is the vine susceptible to as it flowers?
The damaging effects of cold, frost, and wind
What is fruit set?
Successfully pollinated embryos brunches grow into true grape clusters
Each grape is the product of _____________ fertilization.
Individual
What percent of embryo berries go through fruit set?
around 30%
What happens to the embryo bunches that don’t successfully progress to fruit set?
They “shatter” falling from the cluster
As the berries enlarge through July, they _____.
remain hard, high in acidity, and low in sugar
When does veraison begin?
August
What is veraison?
Fourth stage of the life cycle of the vine. Grapes begin to truly ripen.
During veraison, ________ are moved from the _______ to the _______.
Sugars
Leaf system – Fruit
What visual effect on the grape does veraison have?
Grapes soften and change color
Acidity ______ during veraison.
decreases
During veraison, what color shifts happen?
Green to red-black
Yellow to Green
What variety is characterized by uneven ripening?
Zinfandel
When does cane ripening occur?
At the same time as veraison
What is cane ripening?
When the stems on each shoot begin to lignify, accumulating carbohydrates to sustain the plant through winter.
When the grapes have achieved an optimal balance of _____ and _____ they are ready for harvest.
Sugar; Acid
What is vendange?
Harvest
When does harvest occur?
As early as late August and may last through early November
Which grapes are generally harvested first – red or white?
White
What is complete physiological ripeness?
A concept of ripeness comprising not only must weight and pH, but also the ripening of tannin and other phenolics, the condition of the berry and its pulp, and seed lignification
When happens to the vines following harvest?
In autumn, grapes lose their leaves and enter a period of winter dormancy. Fertilization may occur. Vines are pruned to prepare for next years growth.
For equivalent dates for the Southern hemisphere – add _______ months
Six
What does climate encompass?
Expected temperature, Rainfall, Sunshine, wind, and other atmospheric elements
What is weather?
The daily manifestation of climate
What is responsible for vintage variation?
Weather
What generally remains stable from year to year – weather or climate?
Climate
What mean average temperature do vines prefer?
50 degrees to 68 degrees F, with an ideal temperature of 57 degrees
To ripen, red grapes require an average summer temperature of ____, whereas white grapes prefer an average of _____.
Red — 70
White — 66
Where is viticulture generally restricted to?
The temperate bands of latitude between 30 and 50 degrees in the North and South
What is the California Heat Summation index?
Method of classifying climates solely by temperature
How are climates divided in the California Heat Summation index?
Into 5 regions by the number of degree days
How are degree days calculated?
By multiplying the days in each month of the growing season (defined as April 1 through October 31) by the mean number of degrees over 50 for the month.
Temperature and _____ are closely related.
Sunshine
Sunshine is a necessary provider of _____ and _____
light; heat
What is photosynthesis?
Process of plants converting carbon dioxide into organic compounds, including sugars
How many hours of sunshine are required to support viticulture?
1300
Sunshine during the growing season _____ the farther one moves away from the equator.
Increases
Vines in the _____ climates will often enjoy more sunshine than vines in the _____ climates.
Cooler; Warmer
Cloud cover will not greatly impact _____, but will impact _____.
Transmission of light; Transmission of heat
T/F: The vine evolved as a drought resistant plant.
True
Approximately, how many inches of rainfall are required to produce an adequate crop?
20-30 inches
What is water stress?
When a vine receives too little rain. It is a condition that promotes smaller berry size and yields but will lead to interrupted ripening and complete shutdown of the vine if too severe
What happens if a vine receives too much rain?
Fruit quality is diluted and a friendly environment for fungal diseases is created
How can wind negatively affect the vine?
At violent extremes – it can undermine flowering and denude vines.
How can wind positively affect the vine?
Can be detrimental to mold/mildew; also the use of wind machines to battle frost by mixing warmer upper air with cooler air near the ground
What is terroir?
French term defining the complete system of the living vine; The taste of a place
What does terroir comprise?
The choice of grapevine as it relates to its location, topography, soil, climate, and the hand of man upon it
Put the following in order from largest to smallest: Microclimate, Macroclimate, Mesoclimate
Macroclimate
Mesoclimate
Microclimate
What is Macroclimate?
Regional Climate
What is Mesoclimate?
Climate of a particular vineyard
What is Microclimate?
Climate in and around a vine canopy
What is aspect?
Degree and direction of slope
What is essential to distinctions in mesoclimate?
Aspect and Shelter of a vineyard
How do slopes affect the vines?
They provided good drainage and may benefit from increased sunshine, but temperature falls steadily with added altitude.
Canopy management was developed to affect the _____ of a vine
Microclimate
How does canopy management affect the vine?
Exposure to sunshine and the eventual yield
What does canopy management include?
Winter pruning, leaf removal, shoot positioning, and the use of sophisticated trellising systems
In general, _______ soils produce better wines than ________ soils.
low fertility; rich
What type of soils are desireable?
Well-drained, easily penetrable, with good water retention. They permit the vine to dig deeply for water and minerals.
What kind of soil contributes to higher acidity in grapes?
Limestone-rich soils with high soil pH
Wines with a higher acidity have a ______ pH.
lower
What counteracts soil acidity (low pH)?
application of lime
What are clones?
Identical genetic reproductions of a single vine
Why are most of the world’s vines grafted onto American rootstock?
Because they are resistant to Phylloxera
What other reasons are behind a growers selection of a particular rootstock?
Ability to withstand other diseases and drought, its tolerance to salt and lime, and/or its effect on vine vigor
How many years from the grafting/planting before the grapes are suitable for harvest?
Three years
At what year are grapevines considered mature?
Six Years
What defines maturity in a grapevine?
Stabilization of shoot growth and vine annual yield
When is the rootstock considered mature?
Ten Years
When does the yield of grapevines begin to decline?
20 years
At what age are vines often uneconomical to maintain?
After 50 years
What is the advantage of old vines?
Small yields which lead to highly concentrated fruit
Name two examples of valued old vines.
Rhone varieties in Australia
Zinfandel in California
What is vine training?
the processes of pruning, shaping, and trellising the vine
What is the objective of vine training?
to maximize the vine’s performance in local conditions and to keep the canes from touching the ground and establishing new roots
Why are vines tethered to another apparatus?
They have no self-supporting structure
What are the two classifications of the ways vines are trained?
Cordon or Head
What is cordon training?
When the vine has at least one permanent cane that extends from the trunk, called an arm or a cordon. It grows thick and gnarled over time, and fruit-bearing shoots will emerge from it each season.
What is head training?
When the vine has no permanent cordon, and the trunk ends in a knob or head.
Which type of training generally requires a trellising system?
Cordon Trained
Which type of training doesn’t require a trellising system because the vines can be supported by a single stake or not at all?
Head Trained
Where is most winemaking done?
Between the 30th and 50th parallel North and South
What is climate based on?
Weather history
What is weather history
Wind patterns, hours of sunlight, cloud cover, precipitation, temperature
3 levels of climate
Macroclimate
Mesoclimate
Microclimate
Factors that affect climate
Slope, Aspect, Altitude, Trees/Forest, Bodies of water, Geographical features
Climate Hazards
Humidity (mold)
Rain at harvest (diluted grapes)
Frost (especially in spring)
Winds (helps aeration but may damage vines)
Characteristics of cool climate
Grapes are less ripe lower sugar higher acidity less alcohol potential tart and lean flavors
Characteristics of warm climate
Grapes can fully ripen more sugar in the grape must lower acidity high alcohol potential ripe, lush, juicy flavors
Characteristics of a maritime climate
Long, mild growing seasons followed by cool, moist winters
Very humid/lots of precipitation
Examples of maritime climates
Bordeaux, Willamette Valley, Rias Baixas
Characteristics of a Continental climate
4 seasons
extreme variation
short, warm-to-hot growing season
Examples of continental climates
Burgundy, Rioja, Champagne, Rheingau, Niagara Peninsula
Characteristics of a mediterranean climate
Long, warm, and dry growing season with very mild winters
Desirable for winegrowing but danger of drought
Examples of mediterranean climate
Southern Rhone Valley, South Africa’s Coastal region, Sonoma and Napa Counties
Limestone, Chalk, and Tuffeau (Tufa, Tufo)
Areas once covered by water Rich in calcium from deposited seashells Excellent drainage as well as deep-rooting opportunities for vines Marl - calcareous Clay Loam - crumbly clay/sand/silt
Gravel
Loose textured
small stones
excellent drainage and allowing deep vine-rooting
Clay
Finely textured and filled with minerals
Gives nutrients
Water retentive
Sand
Good drainage
Limited nutrient
Protects against phylloxera
Sandstone - compressed sand and mica
Granite
Hard, crystalline rock of extraordinary density
Limits fertility
Volcanic = basalt, Tufa, and Jory soils
Alluvial = fertile, clay, silt, and sand
Schist and Slate
Mineral rich layers
Allows vine roots to penetrate
Flint = Siliceous hard soils, strong mineral flavors (gun flint)
Well known Chardonnay soil
Kimmeridgian clay
Well known Merlot soil
Clay
Well known Sauvignon Blanc soil
Flint
Well known Cabernet Sauvignon soil
Gravel
Well known Pinot Noir soil
Marl
Well known Syrah soil
Granite
Well known Gamay soil
Sand
Well known Riesling soil
Slate
Grape species
Vitis vinifera Vitis Labrusca Vitis Riparia Vitis Rupestris Vitis Berlandieri Vitis Amurensis (China)
Cross
produced by fertilizing the flower of one variety with the pollen of another variety, thus creating a new variety
Famous Crosses
Cabernet Sauvignon, Pinotage, Muller Thurgau, Madeleine Royale, Ruby Cabernet
Cabernet Sauvignon cross
Cabernet Franc x Sauvignon Blanc
Pinotage cross
Pinot Noir x Cinsault
Muller-Thurgau cross
Riesling x Madeleine Royale
Madeleine Royale cross
Pinot x Trollinger
Ruby Cabernet cross
Carignan x Cabernet Sauvignon
Hybrid
Vitis Vinifera x other species
Famous hybrids
Vidal, Geisenheim
Vidal hybrid
Ugni Blanc x Rayon d’Or
Geisenheim hybrid
Riesling x Chancellor
Nematodes
Small roundwords that feed on vine roots
May be responsible for spreading viral diseases
Treatment for Nematodes
Pesticides
Mulching
Virus-free rootstock
Grape Moths
Larvae attack young leaves
Treatment for Grape Moths
Pesticides/Cultural practices
Phylloxera
Root feeding lice that kill vines
Treatment for Phylloxera
grafting onto resistant rootstock
Powdery mildew (Oidium)
Fungal, cobweb like growth that stops photosynthesis/ripening
Treatment for Oidium (Powdery Mildew)
Sulphur
Downy Mildew
Fungal, caused by humidity, cottony growth
Treatment for Downy Mildew
Bordeaux mixture
Pierce’s Disease
Bacterial infection, fatal, spread by sharpshooters
Treatment for Pierce’s Disease
No cure, get rid of sharpshooters
Grey Rot/Noble Rot
Fungal, may be positive for fully ripe grapes or negative for unripe grapes
Treatment for Grey Rot/Noble Rot
Fungicide
Canopy management to control air flow
Coulure
Difficulty at flowering because of cool/wet weather – drops berries
Treatment for Coulure
Adequate varietal for climate
Adequate leaf coverage
Milledrange
Abnormal fruit set
Uneven sized berries
Caused by poor weather
Life cycle of the vine
Dormancy - winter Bud Break - Early Spring Shoot Growth - Mid Spring Flowering + Fruit Set - Late Spring Growth - Summer Veraison - Late Summer Harvest - Fall
Parts of a Grape
Stem, Bloom, Skin, Pulp, Seeds
Stem
provide Tannins
Bloom
provide Yeasts & Bacteria
Skin
provide Flavor compounds, tannins, colors
Pulp
provide sugar, water, acids (tartaric & malic)
Seeds
provide bitter oils
Oxidation
Smells stale or like bad fruits
Exposed to oxygen, change in color
Volatile Acidity (VA)
Acetic Acid or Vinegar
Excess Sulfur
Burnt Matches
Hydrogen Sulfide (H2S)
Rotten egg smell caused by sulphur reacting with lees
May dissipate with aeration
Trichloranisole (TCA or Corked)
Mold, Wet Cardboard
Brettanomyces
Not necessarily a fault depending on personal taste
Wild yeast which can produce various animal - like aromas
Reduction
Boiled cabbage, onions smell
Lack of air contact during vinification
Varieties prone to reduction
Syrah
Sauvignon Blanc
