Viticulture & Vinification Flashcards
What decisions does the viticulturist confront? (8)
Vine training Pruning methods Canopy management Fertilization Irrigation Harvest dates Disease control Monitors development of vineyard in general
What are the 6 stages of a vine’s lifecycle in order?
Budbreak Flowering Fruit Set Véraison Harvest Post-Harvest (pruning)
Budbreak occurs as the average temperature suprasses what temperature in F? When does this usually occur in the Northern Hemisphere? What is produced during this stage? What marks the end of this stage prior to flowering?
50F
Usually occurs in March or April
The first small shoots and leaves will break through the buds
The formation of small green clusters called embryo bunches form marking the end of budbreak and beginning of flowering
During budbreak the vine is most susceptible to what vineyard hazard?
Frost
When does flowering typically occur in relation to budbreak? What three hazards is the vine most susceptible at this point?
Occurs 6-13 weeks after the initial budbreak depending on the climate
Damaging effects of cold, frost, and wind
What stage follows flowering? What is each grape the product of during this?
Fruit Set follows flowering
Each grape is the product of individual fertilization
What percentage of embryos achieve fruit set? What happens to the rest? What happens to the fruit during this stage leading up to veraison?
around 30%
The rest “shatter” falling from the cluster.
The berries enlarge through July and remain hard, high in acidity and low in sugar leading up to véraison
When does veraison typically occur in the northern hemisphere? What happens to the grapes? Does this happen to all grapes on a cluster uniformly?
Typically begins in August
Sugars are moved from the leaf system into the fruit and the grapes soften and change color.
This does not happen uniformly and uneven ripening is not uncommon.
Which grape is notorious for ripening unevenly?
Zinfandel
In addition to the grapes ripening, what else ripens in tandem?
Cane ripening occurs in tandem with grape ripening.
When are grapes ready for harvest? When does this begin at its earliest? Latest?
When the grapes have achieved the optimal balance of sugar and acid they are ready for harvest.
Begins as early as late August and may last through the beginning of November in cooler climates.
Which grapes are generally harvested first, red or white?
Whites are generally harvested first.
What does phenolic ripeness refer to?
Ripeness of tannin and seed lignification
After harvest what happens to the vines?
They lose their leaves and enter a period of winter dormancy
Fertilizer may be applied in the fall after harvest, and the vines will be pruned over in the winter to prepare them for next year’s growth.
What is the difference between climate and weather?
Climate encompasses expected temperature, rainfall, sunshine, wind, and other atmospheric elements, and remains stable form year to year
Weather is the daily manifestation of climate and generally responsible for vintage variation.
For temperature, what does the vine prefer as a mean annual range in F? What summer temperature do grapevines require on average to successfully ripen red grapes? White grapes? What parallels does this generally restrict viticulture to?
Prefers a mean range of 50-68F with an ideal temp of 57 F
Red grapes require an average temp of 70F
Whites require an average temp of 66 F
What is the California Heat Summation Index?
Sometimes known as the Winkler scale
Method for classifying climates solely by temperature
How are degree days calculated for the California Heat Summation Index (Winkler Scale)?
Calculated by multiplying the days in each month of the growing season (April 1-October 30) by the mean number of degrees over 50 F for that month. The months’ totals are then added up to come up with the number of degree days.
What are the six Regions for the CHSI and what are their corresponding degree day value ranges?
Region Ia (1500-2000) Region Ib (2000-2500) Region II (2500-3000) Region III (3000-3500) Region IV (3500-4000) Region V (4000-4900)
What is the minimum amount of sunshine required to support viticulture in hours?
Approximately 1300 hours
Sunshine during the growing season (increases/decreases) the further one moves away from the equator.
Increases the further you move away from the equator.
How much annual rainfall does a vine require to produce an adequate crop?
20-30 inches annually
When do Mediterranean climates receive most rainfall seasonally?
Winter and spring
What happens when too little rain is received by the vine? How does this affect berry size and ripening?
Water stress will occur and this promotes smaller berry size, too much stress and the vine will shut down interrupting ripening.
How does too much rain affect the vine?
The vine itself will not be adversely affected but the berries will dilute the fruit and create a friendly environment for fungal diseases
In what ways does wind adversely affect the vine? How does it provide benefits to the vine?
When its extreme it can undermine flowering and denude vines. In colder climates the chill can be devastating
Provides benefit in the form of serving as detriment to mold and mildew.
Describe the differences between Macroclimate, Mesoclimate, and Microclimate in regards to what each refers to.
Macroclimate refers to larger areas of a region
Mesoclimate refers to the climates within a vineyard
Microclimate refers to to the climate in and around the vine canopy and restricted space including all parts of the vine above the ground
What does well-drained soils encourage in regards to vine growth?
Encourages the vine to dig deeply for water and minerals
What does high soil pH like that found in limestone-rich soils encourage in the grapes?
Higher acidity in the grapes (lower pH)
How can acidic soil, that with a low pH, be treated?
Applications of lime can reduce the effects of low pH
Clones are identical genetic reproductions of a single vine and are selected for a host of different attributes in both the field and the wine. Name 5 attributes commonly selected for.
Disease resistance Hardiness Yield Aromatics Structure Color
Other than colonal selection, what other method for propogating the vine exists? How does it work and what does it promote in the vineyard?
Selection Massale - Budwood from a number of vines throughout the vineyard is selected for replanting. This promotes broader genetic diversity of the vineyard and thus more complexity in the wines.
What is the most common rootstock which vinifera grapes are grafted on to protect the vine from phylloxera?
Vitis Riparia
In addition to resistance to phylloxera, what other three traits are considered when selecting a rootstock?
Ability to withstand diseases and drought
Tolerance to salt and lime
Effect on Vine Vigor
In many European appellations a newly planted vine must not be used for production until it’s at least how many years old? By what year is the grapevine considered mature? What stabilizes for the vine at this time?
At least three years old
By the 6th year the grapevine is considered mature, shoot growth and the vine’s annual yield stabilizes at maturity
How old does a vine have to be for its root system to be considered mature?
Root system will be mature for a vine at 10 years of age.
After how many years will the yield of the vine begin to decline?
After 20 Years
Vine Training encompasses what three practices for the vine? What’s the objective?
Pruning, Shaping, and Trellising
The objective is to maximize the vine’s performance in local conditions and to keep its canes from touching the ground and establishing new roots.
What is a cane?
The product of a green shoot (fruiting cane) hardening to become a woody extension.
What are buds?
Point along the cane that produce a shoot during the spring.
What is a spur?
A spur is a cane cut back to two buds
What are the two most common vine training techniques?
Head-training
Cordon-training
How can head-trained vines be pruned?
Spur-pruned
Cane-pruned
How are cordon-trained vines pruned?
Spur-pruned
What are the two essential methods of pruning?
Spur-pruning
Cane-Pruning
Guyot and Gobelet are pruning techniques for what kind of training method? Which uses cane-pruning? Which uses spur-pruning?
Head-training
Guyot uses cane-pruning
Goblet uses spur-pruning
What are Gobelet-pruned vines called in Spain? Italy? Australia?
En vaso (Spain)
Albarello (Italy)
Bush (Australia)
Cordon de Royat and Geneva are examples of what kind of training? Which is most similar to Guyot? How is it different than Guyot?
Cordon-training
Cordon de Royat is most similar to Guyot, but there’s a single spur-pruned permanent cordon extending from the trunk rather than a two year-old cane
What are the four categories of disease a vine may be subject to?
Fungal
Bacterial
Viral
Phytoplasmic
Fungal diseases are manifested as what two things? What climates are these most prevalent in? What parts of the vine do they typically affect the most? How can they be controlled?
Mildew or Mold
Warm and damp climates are most conducive to these
Typically affect the root system or the canopy
Can be controlled through application of fungicide spray and other applications
How do viral diseases infect the vine? Cure?
Viral diseases spread through grafting or transmission by insects
There is no known cure for many common viral infections, but they can be partially controlled by removal of appropriate sections of the vine for propagation of new, healthy vines.
Which is more devastating usually, bacterial or viral disease?
Bacterial
How are phytoplasma diseases introduced to the vine?
Caused by phytoplasmas, pathogens similar to bacteria, but symptomatically similar to viral diseases, and like viruses must spread through an insect vector or rootstock grafting.
What is Daktulosphaira vitifoliae? How does it affect the vine? How are vines protected from this? What major wine producing country is the only one that is totally free from this?
Phylloxera
Feeds on the roots of the vine destroying the root system
Vines are grafted onto American rootstock such as Vitus riparia to prevent phylloxera’s effect
Chile
Powdery Mildew, Downy Mildew, Esca, Bunch Rot, Eutypa Dieback, and Black Rot are known as what kind of diseases?
Fungal Diseases
Oidium (Uncinula necator) is also known as what in the vineyard? What parts of the vine does it affect? How does timing of infection in relation to the vine’s growth cycle influence these effects? How is it controlled and/or prevented?
Powdery Mildew
Affects all green parts of the plant, marking grapes, leaves, and shoots with dusty white mildew growth
If infected prior to flowering, yields will be reduced
If infected after fruit set, berries will struggle to achieve veraison and reach full size
Application of sulfur and other fungicides is used for control and prevention
