Viticulture and Vinification Flashcards
How many acres are under vine globally and how much fruit do they produce?
a) 19 million acres
b) 70 million tons of fruit
What percentage of cultivated grapes are used in wine production?
70%
What is viticulture?
The intentional cultivation of grapevines
What is the “trunk” of the vine?
The thick central structure of the vine from which the roots extend downward and the arms extend outward and upward.
With respect to the arms of the vine, what are three stages of growth?
Arms begin as SPURS, develop into long, thing CANES, then thicken into CORDONS.
What is the “canopy” of the grapevine.
The leaves and grape clusters that are generally trained to hang down over the lower portion of the structure
Why are grapes rarely propagated from seeds in commercial viticulture?
Too unpredictable and time consuming.
Describe the process of cloning?
Cut off a length of healthy cane, place it in water until it begins to grow roots, then plant it in the vineyard.
Describe the process of field-grafting.
Remove existing branches from a healthy vine, make a small incision in the truck and insert an unrooted cutting from a desirable vine.
How long does it take for a new vine to produce viable fruit, and how long can it continue to do so?
a) the vine will produce grapes during its first year, but they will generally not harvested until the third year.
b) The vine will start to produce optimal quality fruit around year 6 for a decade or more
c) After 20 years, the yield will decrease but quality can become even greater. “Old vines” are often 50 years old and some are over a century old.
Winegrowing is most successful at what latitudes?
Between 30-50 degrees in both hemispheres
What is the dormancy period?
The time during the winter when the vine experiences no growth and much of the training and pruning is done for the following season
What is the first step in the lifecycle of a vine, and at what temperature does it occur?
a) Weeping, the point at which sap from the trunk begins to flow upward to the tips of the canes
b) 50 degrees
What is “bud break” and when does it occur?
a) when tiny shoots sprout from the nodes of the cane, which develop into leaves so photosynthesis can begin.
b) about a day after weeping
When does “flowering” occur?
40-80 days after bud break.
What is the transition from flower to berry called?
Berry set or fruit set
What are two maladies that can affect the vine during fruit set?
1) Coulure–not enough flowers become berries
2) Millerandage–grape bunches have a high number of small seedless berries along with normal ones, caused by bad weather
What is “veraison”?
The sudden acceleration toward maturity, when the grapes change color, sugar is stored and acidity levels drop
What’s the difference between physical and phenolic maturity?
a) physical - refers to sugar levels
b) phenolic - refers to tannin and other phenolic compound development
How long does the period between bud break and harvest usually last?
140-160 days but can be anywhere from 110-200 days
What is photosynthesis?
The process by which sunlight is used by the green parts of the plant to convert CO2 and water into sugar.
What is the catalyst for photosynthesis?
Chlorophyll
What two things is photosynthesis dependent upon?
1) Sunlight
2) Temperature
At what temperature can photosynthesis occur?
50-95 degrees F
What five condition are ideal for photosynthesis to occur?
1) Warm days
2) Long days
3) Clear days
4) Minimal shading
5) Southern aspect (in Northern hemisphere)
What is respiration with respect to plants?
The process by which the plant breaks down sugar, releasing energy for leaf and root growth.
When sugar is unavailable, what substance do plants use for respiration?
Malic acid.
How does temperature affect respiration?
For every 18 degree F, the rate of respiration doubles.
What is transpiration?
The process by which water evaporates through opening on the underside of the leaves known as STOMATA
What are “stomata” and what two functions do they perform?
Small openings on the underside of the leaves through which a) water evaporates and b) carbon dioxide is taken in.
What happens if the stomata close due to lack of water?
CO2 can’t be taken in and photosynthesis stops.
What is translocation?
The process by which substances are moved from one part of the plant to another.
Where is sugar moved during translocation, and why?
Sugars may be moved from the leaves to growing shoots, roots or trunk, or directed to grape clusters when not needed for growth.
What is “terroir”?
The combined natural aspects of the vineyard, such as climate, soil, sunlight and water.
What is the difference between climate and weather?
Weather is the actual meteorological conditions experienced, whereas climate is the historical average weather of a place.
Annual variation in vintages is caused by difference in _________________.
Weather
What are differences between macro-, meso- and micro-climates?
a) Macro - overall region
b) Meso - specific vineyard
c) Micro - a small portion of the vineyard, such as a few rows
What is “canopy micro-climate”?
The conditions that affect the canopy of a specific vine.
Temperature has a great effect on ___________-___________ balance.
Sugar-acid balance
What is “winterkill”?
When the ground freezes several down and permanently damages the root structure of the vine.
When are vines most vulnerable to frost?
At the beginning of the growing season, when a late frost can damage shoot growth or late in the season, when early frost can damage an unharvest crop.
What is arguably the most dangerous form of precipitation for vines?
Hail
How much rain per year do vines generally require?
Between 20-30 inches
When is rain particularly unwelcome during the year?
During harvest, when rain can swell the berries and dilute sugar content
Why is humidity harmful to vines?
Creates ideal conditions for fungus and mold.
When is fog beneficial to vines?
When it forms early and burns off late morning.
What are two negative effects of fog?
a) can inhibit photosynthesis
b) can create conditions ideal for mold
What are two positive effects of fog?
a) can moderate a warm climate
b) can create conditions ideal for Botrytis Cinerea, or noble rot.
Name two positive effects of wind.
a) reduces humidity
b) reduces pests
Name two negative effects of wind.
a) can interfere with flowering and pollination
b) can put significant stress on the vine
How can winegrowers moderate the effects of wind?
Through use of windbreaks and certain training and pruning methods.
What two characteristics do the soils of the world’s greatest vineyards share in common?
1) They are not very fertile.
2) They allow for sufficient water retention but also excess drainage.
What are four types of soil categorized by particle size, in order from smallest to largest?
1) Clay
2) Silt
3) Sand
4) Gravel
What are five geographical factors that affect the vine?
1) Latitude
2) Elevation
3) Topography
4) Aspect
5) Proximity to bodies of water
Describe a Continental Climate.
Hot summers, cold winters, larger diurnal shifts
Describe a Maritime Climate.
Strong influence by an ocean or sea, higher rainfall, mild overall temperatures
Describe a Mediterranean Climate.
Warm, dry summers, mild, wet winters, low humidity
What is a marginal climate?
One so cool that grapes struggle to ripen
What is the best way to prevent viral diseases?
Avoid introducing them to the vineyard via cuttings or grafts.
What is Pierce’s disease?
A bacterial disease spread by the glassy-winged sharpshooter, which causes premature leaf fall.
What are fungal diseases and give two examples.
a) Diseases caused by airborne spores that thrive in warm, humid conditions
b) powdery mildew
c) downy mildew
What is another term for powdery mildew?
oidium
What is another term for downy mildew?
peronospora
What fungus is known as both grey rot and noble rot, depending on the time and grapes in which it develops?
Botrytis Cinerea
What is Botrytis known as in France and Germany?
a) pourriture noble
b) Edelfaule
What are the ideal conditions and grapes for Botrytis?
a) morning fog followed by afternoon sun
b) Semillon, Chenin Blanc, Riesling
What is Phylloxera?
A louse native to the Eastern US that was accidentally introduced to European vineyards in the mid 1800s and went on to devastate most of the vitis vinifera throughout the world.
What ultimately proved the solution to phylloxera?
First, creating hybrids between vinifera and North American species. Then grafting vinifera onto North American rootstock.
What soils are more or less resistant to phylloxera?
Sand
What is a nematode and how does it damage the vine?
a) A roundworm that feeds on the roots of the vine
b) It causes direct damage to the root and also spreads viral diseases.
How can nematodes be combatted?
a) use of nematode resistant rootstocks
b) use of mustard, a natural biofumigant
How can grape growers prevent birds, deer etc. from snacking on grapes?
Use of fencing and netting
When do grape growers perform the majority of their pruning?
Winter
Why would grape growers prune the majority of the nodes from the vine?
Excessive leaf and grape growth spreads the vines resources too thin and comprises the quality of the grapes.
What is cane pruning?
A method by which all but 2 canes per vine are removed, which are normally trained horizontally with 6-10 nodes per cane.
What is spur pruning?
Vines are trained to develop one or more permanent cordons, which can support several canes. Each cane is pruned back to a spur that contains a few nodes.
What is the Guyot system?
A trellising method in which one or two cordons or canes are trained along a wire.
What does VSP stand for and what does it mean?
a) Vertical Shoot Positioning
b) A trellising method in which new shoots are trained upward, with grape clusters hanging below the leaves.
Give three examples of divided canopy systems.
1) Geneva Double Curtain
2) Lyre
3) Scott Henry
What are three terms for free-standing vines?
1) Bush vines
2) Head trained
3) Gobelet-style
What pruning system is used for Gobelet-style vines?
Spur pruning
What is the Pergola system?
Vines are trained upward, then allowed to spread out horizontally, with grapes hanging below.
What determines the time of harvest?
1) ripeness of grapes
2) style of wine
3) weather
4) labor
5) economic considerations
How is sugar concentration in grapes measured in the US
a) degrees Brix
b) using a refractometer
In Brix, what is the conversion factor used to estimate the ABV of a finished wine based on sugar?
5/9 or 55%
____________, a unit used in France, reflects the potential alcohol level in __________ per ___________ milliliters.
a) Baume
b) milliliters
c) 100
What sugar concentration system is used in Germany and Switzerland?
Oeschsle
What is the Oeschle equation?
Oeschle = (density - 1.0) x 1000
What is organic viticulture?
Grape growing without the use of manufactured fertilizers or pesticides
What is the overall governing body with respect to organic grower certifications.
NOP - National Organic Program
In the US, how long must a vineyard be free of banned chemicals before being certified organic?
3 years
Name three ways to achieve organic growing.
1) composting
2) additional mowing
3) natural biofumigants
4) natural predators
What is IPM?
a) Integrated Pest Management
b) a targeted approach to dealing with pests in the vineyard
What is biodynamic viticulture?
Organic growing with some metaphysical elements and some additional mandated procedures
Who invented biodynamic philosophy?
Rudolf Steiner
What organization is responsible for biodynamic certifications?
Demeter International
Name two areas addressed by sustainable viticulture but not by organic growing?
1) climate change
2) water use
What are two regional certifications in sustainable growing?
1) Lodi Rules
2) Napa Green
When should winemaking begin?
As immediately after harvest as possible.
What is the period prior to fermentation commonly referred to as?
Crush
Why do winemakers add sulfur prior to fermentation
When combined with SO2, it prevents the growth of yeast and bacteria. It also prevents oxidation.
What is generally the first step in both white and red wine production?
Sorting
What is the second step of white wine production?
Crushing and Destemming
What is the difference between crushing and pressing?
The skins of the grapes are broken and juice is allowed to flow, but no pressure is applied.
What is a “cold soak”?
The practice of allowing certain aromatic white wines to macerate a short period, usually less than 24 hours
What is the purpose of pressing and when does it occur in white and red wine production?
a) to separate the juice from the skins and other solids
b) white - prior to fermentation
c) red - after fermentation
What is free run juice?
The first juice that drains from the press before any pressure is applied; considered the highest quality
What device is used in pressing to avoid crushing seeds and bursting skin cells?
Bladder press
What is pomace and what can it be used for?
a) The skins and seeds that remain after pressing
b) marc or grappa
What is “must”?
Grape juice destined for fermentation
List three common must adjustments.
a) acidification
b) enrichment
c) chaptalization
What substances might a winemaker use to a) increase acidity or b) lower acidity in the must?
a) tartaric acid
b) potassium or calcium bicarbonate
What is RGMC and why is it used?
a) Rectified Grape Must Concentrate
b) to increase sugar in the must
What does chaptalization do?
Increases the alcohol in the finished wine
What’s the French term for allowing the must to settle for a day or two prior to fermentatinn?
Debourbage
What is the chemical equation for fermentation?
C6H12O6 + yeast -> 2(C5H50H) + 2(CO2) + heat
That just means sugar + yeast yields ethanol, carbon dioxide and heat
What percentage of grape sugars are generally converted to alcohol and CO2 in fermentation?
About 90%
What does the term “inert” mean with respect to fermentation vessels?
Imparts no flavor to the wine–ex. stainless steel tanks or concrete vat
What are two ways to stop spontaneous fermentation?
a) sulfur
b) refrigeration
What is one synonym and one antonyms for spontaneous fermentation?
a) natural fermentation
b) inoculation
What terms are applied to yeast involved in both spontaneous fermentation and inoculation?
a) wild or ambient
b) cultured
What type of yeast is almost always used in winemaking?
Saccharomyces cerevisiae
At what temperature should fermentation take place to preserve delicate qualities in aromatic white wines?
50-60 degrees
What is “stuck” fermentation and what might cause it?
a) yeast die and fermentation ceases
b) temperature rising above 100 degrees
How long does fermentation typically last?
Anywhere from several days to several weeks
Name two reasons fermentation might NATURALLY come to an end.
1) all sugar has been consumed
2) alcohol rises about 14%
Why might a winemaker intentionally halt fermentation before it’s natural conclusion?
To create a sweet or off-dry wine
Name two optional post-fermentation techniques used in white winemaking.
1) Malolactic fermentation
2) Lees contact
Name two other terms for malolactic fermentation.
1) Secondary fermentation
2) Malolactic conversion
What ester imparts a buttery characteristic to wines that have undergone malolactic fermentation?
Diacetyl
What are lees?
Dead yeast
What process is used to removed lees from wine?
Racking
What is the French term for aging on the lees
Sur lies aging
What is battonage?
The French term for stirring the lees to impart more leesy characteristics to the finished wine
Why would the addition of sulfur AFTER fermentation be particularly important in wines with RS?
To prevent unwanted fermentation after bottling
Name four methods of clarification.
1) Racking
2) Filtering
3) Fining
4) Centrifuge
What is racking?
The most basic form of clarification–wine is placed in a container, sediment is allowed to fall to the bottom, wine is placed in a fresh container, repeat.
What three substances used for fining and how do they work?
1) egg white
2) gelatin
3) bentonite clay
4) fining substance binds with unwanted material such as excess tannin or protein, causing it to fall to the bottom
What is sterile filtering and what is its drawback?
1) A type of filtering that uses a barrier with openings so small bacteria cannot pass through.
2) The concern is that desirable characteristics of the wine may be filtered out as well.
What force does a centrifuge use for clarifying wine?
accelerated gravity
What types of white wines benefit from barrel aging?
Fuller-bodied styles such as Chardonnay
What two things may be accomplished by blending?
1) brand consistency
2) added complexity or balance
Cold stabilization requires chilling the wine to __________ degrees.
25 degrees
What is an alternative to cold stabilization?
Contact process–the use of potassium bitartrate to initiate the formation of tartrates.
What is the final step of wine production?
Bottling (or packaging)
Why is crushing/destemming sometimes skipped in white wine production but never in red?
In red wine production, the skins are used during the fermentation process.
What are two ways to add tannin back to the must in red wine production?
1) using the stems
2) adding tannin powder
What step makes the primary difference between red and white wine production?
Maceration–the prolonged contact between the skins and the must during fermentation.
How long does maceration last?
A few days to a few weeks?
What is a cold soak and how does it differ from usual maceration?
When a winemaker chooses to begin maceration BEFORE fermentation, chilling the 55 degrees to prevent fermentation from initiating. In this case the solids are macerating in water as opposed to alcohol, which is a more aggressive solvent, giving the winemaker more control over the levels of phenolics extracted.
In what vessel is red wine fermentation usually conducted?
Large stainless steel tanks.
What is cap management?
The process of breaking up the dense solids that gather at the top of the fermentation value so the skins can be reintegrated with the juice.
What can form in the cap if not properly managed and what does it cause?
a) acetobacter
b) acetic acid
Name four methods of cap management.
1) Punching down
2) Pumping over
3) Rack and return
4) Rotofermentation
What is the French term for punching down?
Pigeage
What is the French term for pumping over?
Remontage
What’s the French term for rack and return?
Delestage
What fermentation temperature might a winemaker choose for a light Pinot Noir?
60-70 degrees
What fermentation temperature might a winemaker choose for a robust Cabernet Sauvignon?
85-95 degrees
What is extended maceration?
When a winemaker chooses to leave the wine in contact with the skins AFTER fermentation is complete.
Why is malolactic fermentation conducted more often in red wines than in white?
1) decrease acidity
2) stabilize the wine by decreasing malic acid
When is pressing conducted in red wine production?
AFTER fermentation/extended maceration
Why are red wines typically clarified LESS than white wines?
To prevent the removal of desired phenolics.
What is the effect of new wood as opposed to old wood in barrel aging?
New wood imparts flavor, old wood imparts only oxygen
What is the effect of aging in small barrels as opposed to large barrels?
Small barrels impart more flavor because the wine to surface area ratio is greater.
What is the effect of American Oak compared to French Oak?
a) American – larger grain, more assertive, coconut and dill
b) French - finer grain, more subtle, baking spice and vanilla
Name 4 factors in barrel aging that affect the character of the wine?
1) Age
2) Size
3) Country of Origin
4) Level of Toast
How much does a new French barrique cost?
About $1300
What is micro-oxygenation?
The practice of introducing tiny bubbles of oxygen into the wine to mimic the affects of barrel aging.
What is carbonic maceration?
An alternative style of red winemaking that requires neither yeast nor bacteria, but involves intracellular fermentation and takes place in the absence of oxygen.
What region is best known for CM and what characteristics does it impart?
1) Beaujolais
2) Bright red fruit, banana, bubblegum
What typically determines the color of rose wine?
The amount of time the juice remains in contact with the skins.
What are two ALTERNATE methods of rose wine production?
1) co-fermentation of red and white grapes
2) blending red and white finished wines
How long is maceration period in rose wine production?
A few hours to a few days?
What is the saignee method?
Red grapes are crushed and vatted for up to 20 hour, then a small amount of juice is “bled” off to make the rose. The red grapes continue to macerate and are used to make a concentrated red wine.
What is the “direct press” method and what is the term often used for the finished wine?
a) A method of rose production by which the juice is pressed after a very short period of maceration, resulting in a pale pink wine.
b) Vin Gris
What term is often used for Rose that is a) slightly sweet or b) made from a single varietal?
a) blush
b) white
What are the terms for rose in a) Italy b) Spain c) Germany?
a) Rosato
b) Rosado
c) Weissherbst
What are “flying winemakers”?
Winemakers that fly between North and South hemispheres to make wine twice a year
What are four methods for producing sweet wine?
1) Using grapes affect by Botrytis
2) Late harvesting
3) Drying the grapes
4) Harvesting frozen grapes
What is the most famous region for Botrytis-affected wines?
Sauternes, but also areas in the Loire Valley
Why do Chenin Blanc and Semillon have a particular affinity for Botrytis?
Thin skins
Describe the aromas produced by Botrytis?
apricot and honeysuckle
What climates and grapes are best for late harvesting, and why?
a) cool climates
b) Chenin Blanc and Riesling
c) grapes continue to gain sugar late in the season, but they also lose acidity, so cool climates and naturally high acid grapes help retain balance
Where is the drying method most common?
The Mediterranean
How late are grapes used for Icewine production harvested?
As late as January or February
What red grape is sometimes used for Icewine production?
Cabernet Franc
What is the term for a mechanized freezing process that mimics Icewine production?
Cryoextraction
Name three PROCEDURES for making sweet wine.
1) Refrigeration to stop fermentation
2) Addition of sugar, grape concentrate or RGMC
3) Fortification to stop fermentation
What are two additional methods of halting fermentation?
1) Pasteurization
2) Sulfur
What are the NOP’s labeling requirements for “Organic Wine”?
a) use of 95% organic grapes
b) no use prohibited substances
What is the most significant restriction when it comes to organic wine?
The prohibition of sulfur additions
When can a wine use the term “Made with Organic Grapes”
a) use of 100% organic grapes
b) sulfur additions lower than 100 ppm
In the EU, how are organic wines labeled and what are the requirements?
a) Organic Wine or Vin Biologique
2) 30% to 50% less sulfur addition, so additives, fully traceable winemaking process
Why is Biodynamic winemaking less strict than organic winemaking?
a) it’s based on a set of philosophies and goals rather than strict rules
b) sulfur additions are permitted if kept to a minimum
c) it is overseen by a private organization rather than a government organization
What is one of the few prohibitions in biodynamic winemaking?
the use of genetically modified material
When and where is orange wine believed to have originated?
a) Georgia
b) 5000 years ago
What gives orange wine its copper hue?
Prolonged maceration with the skins
Name four rules in the production of Kosher wine.
1) grapes can only be handled by male Orthodox Jews from the time they arrive at the winery under the supervision of a rabbi.
2) winemaking equipment must be used for no other purpose
3) no animal-based material, such as egg white may be used
4) once opened, wine can only be handled by observant Jews
What is the term for Kosher wine free of restrictions on those who handle it?
Meshuval wine
