Viticulture Flashcards
How many acres are under vine worldwide, however tons of fruit are produced, and how much of that fruit is used to make wine?
19 million acres, 70 million tons, 70%
What is the branch of agriculture that concerns the intentional cultivation of grapevines?
Viticulture, or winegrowing.
What are vines comprised of?
A single trunk, roots, one or two arms, which start as spurs that develop into canes, and eventually thicker cordons; leaves, tendrils, berries.
What does the canopy refer to?
Arms, leaves, berries
How are grapevines propagated in viticulture?
Cloning, which consists of cutting off a short length of can, placing it in water so that it starts to grow roots, and planting it in the vineyard.
Also field grafting, which consists of making a small incision in the trunk and inserting an unrooted cutting.
How long does it take a new vine to produce quality fruit.
The first crop is usually harvested during the third year, but it takes an average of six years to produce quality fruit. Vines produce fewer berries after 20 years but can continue to produce fruit for a hundred years or more.
Where are grapes typically grown?
Between 30-50 degree latitude in both Northern and Southern hemispheres.
When does harvest happen in the Northern and Southern hemisphere.
Roughly six months apart, in October of later for the Northern hemisphere, April or later in the Southern.
What is the first step of the annual growth cycle?
After a period of winter dormancy, “weeping” begins when temperatures reach 50 degrees, followed by bud break.
What begins once the vine has developed leaves?
Photosynthesis, which accelerates growth.
When does flowering occur?
40-80 days after bud break
How are berries formed?
When a flower is fertilized by pollen from another part of the plant.
What is coulure and millerundage?
“Shatter” - too many flowers failing to become fully developed berries;
Uneven or abnormal development
What is veraison?
When the grapes begin to change color and enlarge, signaling an acceleration to maturation
When does harvest generally take place?
a month and a half or two after veraison.
What is physiological maturity?
When the levels of phenolic compounds including tannins are sufficient to produce the color, flavor and aroma of wine.
What happens independently of physiological maturation?
Sugar concentration, though it happen at the same time but often at a different rate.
How much time elapses between budbreak and harvest?
110-200 days, normally between 140-160
What happens during the winter?
dormancy and pruning
What are the key areas of grapevine metabolism?
Photosynthesis, respiration, transpiration and translocation
What is photosynthesis and what does it require?
The process by which chorophyll-containing parts of the vine use sunlight to convert CO2 to water and sugar.
It requires sunlight and temperature - 50-95 degrees.
What are five key conditions optimal for photosynthesis?
Warm days Long days Clear Days Minimal Shading Southern Aspect (flip that for Southern Hemisphere)
How does distance from equator affect sunlight?
1) Locations further from equator have longer summer days
2) Locations further from the equator receive the sun’s rays at a lower angle.
What is respiration?
Respiration occurs when the plant breaks down sugar and other carbs, releasing their energy for root and leaf growth.
What can a vine metabolize when sugar is unavailable?
Malic acid; for ex, during veraison. This CAN affect the wine’s flavor.
How does temperature affect respiration?
For every 18 degree F increase in temp, the rate of respiration doubles.
How does respiration affect acidity?
The warmer it is, the faster respiration takes places, and the faster acid levels drop. Cool nights minimize acid loss during a time when photosynthesis is not taking place.
What is transpiration?
The process by which water evaporates through openings on the underside of the leaves known as stomata.
What is the rate of transpiration dependent upon?
Weather–it’s highest under sunny, hot, windy, dry conditions.
What happens if a plant does not receive enough water?
The stomata will close, which also ceases photosynthesis and the intake of CO2.
What is translocation?
Movement of materials from one part of the plant to another, for ex the movement of sugar from the leaves to growing shoot tips.
What happens to sugars not needed for energy?
They may be directed to the grape clusters or stored in the woody parts of the vine for future use.
What does terroir mean?
No direct translation; the combined natural aspects of a vineyard, such as climate, soil, sunlight and water.
