Viticulture and Vinification Study Guide Flashcards
What 6 things does the grower or viticulturist confront decisions on?
vine training canopy management fertilization and irrigation harvest dates disease control the development of the vineyard in general
What do advances in viticulture aim to reduce?
The vagaries of weather and disease, and promote either the quantity or quality of wine.
When does the annual life cycle of the vine begin? When does this happen? What happens during this stage?
budbreak; occurs in March or April in Northern Hemisphere
the first small shoots and leaves will break through the buds left intact by winter pruning
What does “weeping” or “bleeding” refer to in regards to a vine? When does this occur? Before what stage in the vine’s life cycle does this occur? What average air temperature triggers this?
refers to the running of watery sap from pruned canes sometime in February (Northern Hemisphere)/August (Southern Hemisphere) when a vine emerges from dormancy
Occurs prior to bud break when average air temperature surpasses 50F
What hazard is the vine most vulnerable to during bud break?
frost
What happens between bud break and flowering.
The vine’s foliage continues to develop and small green clusters called embryo bunches form on the shoots by mid-April
What stage follows budbreak? How many weeks afterwards does this happen? What happens during this stage?
Flowering; embryo bunches bloom into small flowers for about 10 days, and the self-pollinating grapevine begins the process of fertilization, leading up to fruit set.
This occurs 5-12 weeks after bud break
What are the 3 main hazards to a vine during the flowering stage?
damaging effects of cold, frost, and wind
What stage follows flowering? What happens during this stage?
Fruit set; successfully pollinated embryo bunches grow into true grape clusters during fruit set- each grape is the product of individual fertilization.
What % of embryos successfully fertilize during fruit set to produce grapes on the cluster? What happens to the rest?
around 30%; the rest “shatter” falling from the cluster
What does “shatter” refer to in regards to a grape’s growth cycle?
Refers to the falling off of unfertilized embryos during fruit set
What are the berries like in regards to form and makeup leading up to veraison following fruit set?
hard, high in acidity, and low in sugar
What stage follows fruit set in the vine’s growth cycle? What happens here? What happens to the grapes in regards to color and chemical makeup?
véraison; the grapes begin to truly ripen, as sugars are moved from the leaf system to the fruit.
The grapes soften and change color-turning from green to red-black or yellow-green-and acidity decreases
Does véraison happen uniformly on a grape cluster or individually? What grape demonstrates this best?
Véraison happens on a grape to grape basis. Some grapes such as Zinfandel are notorious for uneven ripening.
What happens to the canes of a vine during véraison as the grapes ripen?
Canes ripen in tandem with véraison, as the stems on each shoot begin to lignify, accumulating carbohydrates to sustain the plant through the winter.
When are the grapes consider ready for harvest?
Once the grapes have achieved optimal balance of sugar and acid, they are ready for harvest.
What does vendange refer to?
the harvest
When does harvest occur in the Northern Hemisphere?
May start as early as August and last through the beginning of November
Which are harvested first generally, white grapes or red grapes?
White grapes if used for table wine. Late harvest grapes may hang longer than reds in isolated cases where they may hang on the vine until late November or December
What does physiological ripeness refer to?
refers to must weight and pH along with the ripening of tannin and other phenolics, the condition of the berry and its pulp, and seed lignification, which often requires longer “hang time” for the grapes on vine
What happens regarding the vines in the autumn and winter months following the harvest?
The vines lose their leaves and enter a period of dormancy and fertilizer may be applied in the autumn.
Vines are pruned in the winter months to prepare for the next year’s growth.
What is the difference between climate and weather? Which is most responsible for vintage variation?
Climate encompasses expected temperature, rainfall, sunshine, wind, and other atmospheric elements, and remains relatively stable from year to year
Weather is the daily manifestation of climate, and is generally responsible for vintage variation
What is the range of average mean temperatures annually that the vine prefers? What is the most ideal temperature?
To successfully ripen, what mean summer temperature do red grapes require? White grapes?
50-68F; the most ideal temperature is 57F
Red Grapes require a mean summer temperature of approximately 70F
White Grapes require a mean summer temperature of approximately 66F
Due to temperature requirements, viticulture is generally restricted to between what two latitudes in both hemispheres?
30-50th parallels
What does the California Heat Summation Index do? How many regional categories are there for this?
Classifies climates solely by temperature and therefore recommends varieties appropriate to that temperature
There are 6 categories: Ia, Ib, II, III, IV, V
The California Heat Summation Index classifies climates in 6 categories (Ia-V) based on the number of degree days the climate experiences? How are degree days calculated?
What are the degree days ranges for each category?
Degree days are calculated by multiplying the days in each month of the growing season (defined as April 1-October 31) by the mean number of degrees over 50F for that month. The months’ totals are then added together to arrive at the heat summation category.
Region Ia: 1,500-2,000 degree days Region Ib: 2,000-2,500 degree days Region II: 2,500-3,000 degree days Region III: 3,000-3,500 degree days Region IV: 3,500-4,000 degree days Region V: 4,000-4,900 degree days
Calculate this AVA’s California Heat Summation Index region:
Average Mean Temperatures: April: 58 F May: 62F June: 68F July: 80F August: 79F September: 76F October: 70F
April: 30 x 8=240 May: 31 x 12=372 June: 30 x 18=540 July: 31 x 30= 930 August: 31 x 29= 899 September: 30x 26=780 October: 31x20=620
Total: 240+372+540+930+899+780+620= 4,381
Region V as it is between the range of 4,000-4,900 degree days
What does sunshine contribute to a vine?
Contributes light and heat; enables a plant to photosynthesize, in which the plant converts carbon dioxide into organic compounds, including sugars
What is the minimum amount of sunshine required to support viticulture?
1250 hours but 1500 preferred
Which climates generally receive more sunshine during the growing season, warmer or cooler?
Cooler climates receive more sunshine during the growing season as the amount of sunshine increases as you move away from the equator
Will cloud cover effect the transmission of light to a vine? What does it inhibit?
Won’t affect transmission of light for photosynthesis but will affect the amount of heat the vine receives
What amount of rainfall annually does a vine require in order to produce an adequate crop? What does this depend on?
10-30 inches annually depending on the warmth of the climate
What is the most ideal climate for quality winemaking vines? Why?
Mediterranean
Receives an abundance of rain but in the winter and spring while remaining dry throughout the summer
What are the benefits of less rainfall? What are the downfalls?
Less rainfall will promote smaller berry size and naturally reduce yields but will interrupt ripening and will lead to complete shutdown of the vine if the water stress is too severe.
What can excessive rain lead to regarding the quality of fruit and disease pressure?
Creates higher fungal disease pressure and dilutes the fruit quality
How can wind adversely affect the vine? What benefits can it provide to the vine?
Can undermine flowering and denude the vine.
In cool climates can deliver devastating wind chills
The benefit it contributes is it can be a detriment to mold and mildew and can even mix warmer air from above with cooler air below to mitigate the threat of frost with the use of windmills
What are the three types of climate a vine is subjected to? What does each refer to?
Macroclimate:
Refers to the regional climate; a larger area that shares a similar climate. For example the Napa Valley floor, the Médoc, a south facing slope of the Rheingau. Broad assertions about a region’s suitability for viticulture can be drawn from the Macroclimate
Mesoclimate:
Refers to the climate of a particular vineyard. The aspect and shelter of a vineyard are essential to distinctions in mesoclimate. Large appellations like Corton may have several mesoclimates within the one macroclimate
Microclimate:
refers to the space in an around the canopy and the space on the vine above ground
What viticulture techniques affect a vine’s microclimate?
Techniques of canopy management such as winter pruning, leaf removal, shoot positioning, and the use of sophisticated trellising systems.
What 4 properties make up the most ideal soil type for vines?
well-draining
easily penetrable
good water retention
heat-retaining (and reflecting) depending on the climate
Higher or lower soil pH contributes to lower pH in wine grapes and thus higher acidity in the resulting wines? Name a great example of soil type that lends high acidity to grape vines.
High soil pH contributes to low pH in grape vines
Limestone is a great example of this soil type.
What treatment can be applied to low pH soils to raise the pH?
Lime/wood ash
What attributes are considered generally when selecting a particular grape clone?
disease resistance hardiness yield aromatics structure color
What is the difference between clonal selection and mass selection (selection massale)?
Clonal selections are identical reproductions of a single vine.
Selection massale involves the selection of budwood for replanting from a number of vines throughout the vineyard, rather than a single clone.
What is aim of mass selection? What is the result?
To reinforce positive traits and eliminate negative traits through appropriate selection.
The results may be less precise than those gained through clonal selection but genetic diversity is maintained
What species of American vine’s rootstock was the major contributor to phylloxera resistance?
Vitis riparia
What attributes are considered when selecting a rootstock?
resistance to phylloxera
ability to withstand other diseases and drought
tolerance to salt and lime
its effect on vine vigor
At what age does a vine begin to produce a crop of grapes suitable for harvest? By what age is a grape vine considered mature? What stabilizes then?
Starts at age 3; many European appellations prohibit growers from harvesting grapes for wine until the vine is at least 3 years.
Grapevines are considered mature by age 6. Shoot growth and the vine’s annual yield, in the absence of major stresses, stabilize
At what age does a grape vine’s root system become mature?
By age 10
At what age will the grape vine’s yield begin to decline? At what age is it uneconomical to maintain a grape vine?
After 20 years yield declines; after 50 years it becomes uneconomical though exceptions exist as the naturally low yields can produce incredible concentration in grapes such as old-vine Zinfandel and Rhône varieties
What is the main objective of vine training?
To maximize the vine’s performance in local conditions and to keep its canes from touching the ground and establishing new roots.
What are the two methods of vine training? How do they differ at the basic level? Which requires a trellising system?
Head training and cordon training
In cordon training, the vine has at least one permanent cane that extends from the trunk, called an arm or cordon. it grows thick and gnarled over time, and fruit-bearing shoots will emerge from it each season.
Head-trained vines have no permanent cordon, and the trunk ends in a knob or head.
Cordon-trained vines require a trellising system. Head-trained vines rarely require trellising as they’re self-sustaining by nature and don’t need an apparatus such as a tree, stake, or wire trellis to stand upright.
What is an example of a head-training method that requires a trellis?
Guyot
How many spurs does a cane-pruned vine have? How many canes grow during the growing season? How many are retained following the season? What type of vine training uses cane-pruning?
One permanent spur
Two canes grow from the spur, one of which was retained form the previous pruning and contains the buds from which the shoots will emerge.
The newly grown cain will be retained and will be the source of the following year’s clusters. The 2 year old cane will be removed.
Head-trained vines use vine pruning.
What type of vine training system uses spur-pruning only? Which type of training system can be either?
Cordon-trained vines are spur pruned only
Head-trained vines can be cain or spur pruned
What are the two types of vine training? Two types of pruning?
Cordon-training and head training
Cane-Pruning and spur-pruning
What type of training/pruning combo does Guyot employ?
Head-training with cane pruning
What is the simplest form of head trained/spur pruned vine?
Gobelet
What is Gobelet training called in Spain? Italy?
In Spain it is called “en vaso”
In Portugal it is called “albarello”
What do the terms “en vaso” and “albarello” refer to?
They are both synonymous with the Gobelet spur-pruned/head-trained vine system common in the Southern Rhône and Southern Italy
En Vaso is the Spanish term for it
Albarello is the Italian term for it
Cordon de Royat is an example of what training and pruning combo? Where is this system commonly used?
Cordon-trained/spur-pruned
Commonly used in Champagne for Pinot Noir
What are three examples of spur-pruned/cordon-trained vine systems?
Cordon de Royat
Geneva
Lyre
If a vine is trained using the Tendone system, how does it grow? How is it pruned? What is the purpose of this? What is this system called in Italy? What is this system called in Portugal?
Grows upward and overhead along wooden frames or trees. Can be either spur-pruned or cane-pruned.
Trained so that workers to pass underneath. Also promotes good circulation and protection from frost.
Called Pergola in Italy and Enforcado in Portugal
What are the Italian synonyms for Gobelet and Tendone training systems respectively?
Albarello (Gobelet)
Pergola (Tendone)
What are the four main groups of vineyard diseases?
fungal
viral
bacterial
phytoplasma
In what two ways are fungal diseases manifested? What do they attack? How are they spread? What only needs to be infected to spread though the entire vineyard?
mildew or mold
attack either the root system or canopy of the grape vine
fungal spores are spread by wind and rain
only a single vine needs to infected for the fungus to spread through the entire vineyard
What are the two most notable fungal diseases?
powdery and downy mildew
How can fungal diseases be treated?
With fungicide sprays and other applications
How do vines contract viral infection? Are they curable?
Through grading wounds or from insects. They are generally not curable
What happens to vines affected by viruses?
Their life span is shortened
yields are reduced
quality of fruit is changed
If viral diseases can’t be cured, how are they controlled?
Controlled through removal and appropriate selection for propagation.
What kind of disease is also known as “grapevine yellows”? What spreads it?
flavescence doree/Phytoplasma disease
Leafhopper
Phytoplasmas are similar to what but spread like what?
Similar to bacteria but spread like virus through insect vectors
What is Daktulosphaira vitifoliae?
Phylloxera
What does Phylloxera attack killing the vines in the process?
Attacks the root system of vines
What are three insects that pose disease threats to a vineyard?
mealy bugs
nematodes
glassy-winged sharpshooters
Oidium and Pernospora are known as what two fungal diseases respectively?
Oidium (Powdery Mildew) Downy Mildew (Peronospora)
What is Uncinula necator?
What part of the grapevine does it affect?
What does it look like?
What two things does it greatly inhibit?
How does it affect the vine before flowering and after fruit set?
Oidium/Powdery Mildew)
This fungal disease affects all the green parts of the vine including the grapes, leaves, and shoots.
Looks like a dusty white growth
Greatly inhibits bunch development and ripening
Yields will be reduced if it infects the vine prior to flowering. Berries will struggle to achieve veraison and reach full size if infected following fruit set.
What is Plasmopara viticola better known as? What part of the vine does it affect? What does it inhibit as a result? What does it look like? Can it survive winter? What is used to treat it?
Downy Mildew/Peronospora
This fungal disease affects the leaves of the vine causing them to fall off.
Inhibits vine’s ability to photosynthesize
First symptoms look like an oil spot on leaves. As the spores germinate a white, cottony growth develops on the underside of the leaves.
Can survive on the fallen leaves through winter and can infect the vines again with rain splatter the following season.
Bordeaux mixture, a spray of copper sulfate, water, and lime can prevent outbreaks
