Viticulture/Vinification Flashcards
What species of vine is responsible for fine wine production?
Vitis vinifera is the species domesticated around 5,000 BCE, producing nearly all of the world’s fine wines.
Define viticulture.
Viticulture is the study and practice of grape growing, focusing on training, pruning, canopy management, fertilization, harvest timing, disease control, and overall vineyard development.
Name three historic advancements in viticulture.
1) Charlemagne’s directive to plant vineyards on warm slopes, 2) Grafting V. vinifera onto phylloxera-resistant rootstocks, 3) Modern drip irrigation and mechanization to improve yields and quality.
How does modern viticulture address sustainability?
While science and mechanization dominate many vineyards, new movements like organic, biodynamic, and sustainable viticulture have emerged, reducing chemical inputs and encouraging biodiversity.
When does budbreak typically occur in the Northern Hemisphere?
Budbreak usually occurs in March or April, once the average air temperature surpasses 50°F. The vine is vulnerable to frost damage at this stage.
Describe the process of flowering and fruit set in grapevines.
Six to thirteen weeks after budbreak, the vines flower for ~10 days. Pollinated embryo bunches develop into grapes; fruit set is typically ~30%, with the rest dropping off (coulure).
What is veraison?
The stage when grapes soften, change color (green to red/black or yellow-green), and begin to accumulate sugar as acidity decreases. It marks the true onset of ripening.
Explain physiological ripeness.
Beyond sugar and acid, it includes tannin, phenolic, and seed ripeness, plus the condition of the pulp and berry. It often requires longer “hang time,” especially in modern New World winemaking.
What happens to the vine after harvest?
The vine loses leaves in fall, enters dormancy in winter, and is pruned to prepare for the next cycle. Fertilization may be applied in fall; the cycle restarts in spring with budbreak.
How do climate and weather differ in grape growing?
Climate is the expected, long-term pattern of temperature, rainfall, wind, etc., while weather is the daily manifestation of those elements—responsible for vintage variation.
What is the preferred temperature range for Vitis vinifera?
Between 50° and 68°F mean annual temperature is suitable. Red grapes need ~70°F in summer, whites ~66°F. This restricts viticulture generally to latitudes 30°–50° N or S.
What is the Winkler (Heat Summation) Index?
It’s a system that classifies wine regions by degree days (base 50°F) over the growing season (April 1–Oct 31). Regions range from Ia (<2,000° days F) to V (4,000–4,900° days F).
How much rainfall does a vine typically need?
Approximately 10–30 inches (25–76 cm) of annual rainfall are required, though irrigation can supplement rainfall where legal.
Define terroir.
Terroir is the holistic system of factors influencing vine development: grape variety, climate, soil, topography, and human intervention. It shapes a vineyard’s unique sense of place.
Explain macroclimate, mesoclimate, and microclimate.
Macroclimate is the regional climate. Mesoclimate is the climate of a single vineyard. Microclimate is the environment inside and directly surrounding the vine canopy.
What soil characteristics generally benefit vines?
Low fertility, good drainage, and adequate water retention. Heat retention or reflection, soil pH, and mineral composition also play key roles in vine health and fruit quality.
What is massal selection (sélection massale)?
A vineyard propagation method using budwood from many vines to maintain genetic diversity, rather than relying on a single clone. It can reinforce positive traits across the vineyard.
Why are most vines grafted onto American rootstock?
To protect against phylloxera, an aphid that attacks V. vinifera roots. American vines are resistant, so grafting prevents destruction by phylloxera.
When is a newly planted vine ready to harvest fruit?
Typically, usable grapes appear in the third year. Many regions legally forbid grape usage for wine until year three. Vines reach maturity around the sixth year.
What is the main goal of vine training?
To optimize vine performance—balancing yield, fruit exposure, and canopy management—while keeping canes off the ground. This can be done with stakes, trellises, or bush vine systems.
Differentiate head training vs. cordon training.
Head-trained vines have no permanent cordon; the trunk ends in a “head,” from which canes or spurs grow. Cordon-trained vines have at least one permanent arm extending from the trunk, bearing spurs.
What is spur pruning?
It involves cutting a cane back to two buds (“spur”). Each season, new shoots and fruiting canes emerge. Cordon-trained vines are typically spur-pruned; head-trained vines can be spur or cane-pruned.
Name two classic spur-pruned systems.
Cordon de Royat (common in Champagne for Pinot Noir) and Gobelet (bush vines, used in Southern Rhône/Italy/Spain).
Give an example of a cane-pruned system.
The Guyot system, developed by Jules Guyot, typically has one cane (plus a renewal spur) on a vertical trellis. Double Guyot has two canes extending from the trunk.
What is canopy management?
The set of practices (shoot positioning, leaf removal, trellis design, etc.) that control the vine’s microclimate, optimizing sunlight and airflow around the grapes.
List four categories of vine diseases.
Fungal (mildews, rots), bacterial (Pierce’s disease, Crown Gall), viral (leafroll, fanleaf), and phytoplasma (Flavescence Dorée). Each can reduce yields or kill vines.
What is phylloxera, and how is it controlled?
A root louse from North America that devastated European vineyards in the 19th century. Most vines are now grafted onto resistant American rootstocks to prevent phylloxera damage.
How do powdery and downy mildew differ?
Both are fungal, but powdery mildew thrives in warm, humid conditions, not requiring rainfall; downy mildew develops in damp conditions, showing cottony spores on leaf undersides. Both reduce yields and quality.
Define noble rot and grey rot.
Both are forms of Botrytis cinerea infection. Under beneficial conditions (warm days/cool damp mornings), it’s noble rot (sweet wines). Under destructive conditions, it’s grey rot, spoiling grapes.
What is Pierce’s Disease?
A bacterial disease transmitted by the glassy-winged sharpshooter, lethal to vines (1–5 years). Common in the southern US and moving north in California. No known chemical cure.
Describe a virus that impacts yields significantly.
Leafroll Virus reduces yields and delays ripening, causing leaves to curl downward. It’s incurable but doesn’t kill the vine; removal is often recommended to slow spread.
What is biodynamic viticulture?
A holistic approach introduced by Rudolf Steiner, viewing the farm as a self-sustaining organism. It uses lunar/astrological calendars, special compost preparations, and aims for cosmic harmony. Certified by Demeter.
How do organic rules differ for wine in the US?
To label “organic wine,” grapes must be organically grown, and no sulfites added. “Wine made from organically grown grapes” allows sulfites. EU rules differ, permitting some SO2 in organic wines.
What does sustainable viticulture entail?
Reducing chemical inputs, employing IPM, encouraging biodiversity, minimizing water/energy usage, focusing on soil health, and balancing environmental, social, and economic factors.
Which process transforms grape juice into wine?
Alcoholic fermentation, where yeast metabolizes sugar into alcohol and CO2. Heat and volatile compounds (acetaldehydes, fusel oils) are produced as byproducts.
When might a winemaker use cultured yeast vs. ambient yeast?
Cultured yeasts ensure control, predictable ferment, and can handle higher alcohol. Ambient yeasts are less predictable but may add complexity to the wine.
Explain stuck fermentation.
It’s when yeast activity halts prematurely, leaving unfermented sugar. Modern temperature control and nutrient additions have lowered the incidence but it still occurs.
Distinguish chaptalization and acidification.
Chaptalization adds sugar to must to raise alcohol. Acidification adds acid (often tartaric) to correct or boost acidity. Both are regulated by region’s laws.
Define malolactic fermentation (malo).
Lactic acid bacteria convert sharp malic acid into softer lactic acid, releasing CO2. It rounds out mouthfeel and can impart a buttery aroma (diacetyl) in some wines.
What is carbonic maceration?
An anaerobic fermentation inside whole, uncrushed grapes. Berries begin fermenting internally, producing a small amount of alcohol and distinct fruity flavors, often used in Beaujolais Nouveau.
Compare free-run wine vs. press wine.
Free-run is the juice released without pressing, generally higher-quality. Press wine is extracted under pressure from pomace, richer in tannins and sometimes added in small amounts to enhance structure.
Why do winemakers rack wine during maturation?
To remove sediment (lees), clarify the wine, and introduce controlled oxygen exposure. Racking typically occurs multiple times until bottling.
Explain fining and filtration.
Both clarify and stabilize the wine. Fining adds agents (bentonite, egg white, etc.) to precipitate solids. Filtration passes wine through pads or membranes to remove particles and microbes.
How is white wine production different from red?
White grapes are pressed before fermentation. Skins are usually removed, though brief skin contact can occur. Fermentations are cooler, focusing on fruit/acid; many white wines do not undergo extended maceration.
What is cold stabilization?
Chilling the wine to around 25°F so tartrate crystals can precipitate out. This prevents “wine diamonds” from forming in the bottle later.
How do rosé wines acquire color?
Either by blending red and white wine (often disallowed in still wines but used in rosé Champagne) or via limited skin contact (“maceration”). Saignée is a subset method, “bleeding” off pink juice from a red ferment.
How does oak affect wine?
Oak allows gentle oxygenation, adds flavor (vanillin, lactones), and wood tannin. New barrels impart more flavor; older barrels become neutral. Toast level and origin (French/American) strongly influence character.
Why is the concept of the future of winemaking complex?
Wine is simultaneously an agricultural, scientific, and commercial product. Balancing sustainability, natural methods, and modern technological interventions is an ongoing debate for producers and consumers.
American Oak vs French Oak Names
Quercus Robur - French
Quercus Alba - American
Root Stocks (5)
Vitis Vinifera - Europe (Common)
Vitis Raparia - American (Riverbank)
Vitis Rupestris - American
Vitis Berlandieri - American
Not apart of it: Vitis Labrusca - Fox Grape (Concord)
