2021 Viticulture Flashcards
(109 cards)
What were the two greatest setbacks in wine history and when did they happen?
Botrytus Cinera - a powdery mildew that was first seen in France in 1847 and it destroyed entire vantages.
Phylloxera - a plant louse insect which arrived in Europe on seedlings brought from America first seen in 1863 France. They ate their way through Europe halting production for decades. Entire species of grapes were wiped out.
Remedy not found until 1910
What parallels represent the world’s wine regions?
Europe - between 40th and 50th parallels
Southern Hemisphere between 30th and 40th parallels
What do ‘fine’ wines need regarding ripening?
Lower temperatures- the ripening needs to be slowed down - this prevents it from becoming overly alcoholic or heavy. Also it retains a bit of acidity, an element that adds elegance to white and red wines
Where are wines produces in marginal climate areas outside standard latitudes?
North = Parts of Mosel and Rhine regions (51 north)
South = Southern Europe and North Africa (36 latitude)
A deliberate move into cool regions of the pacific climate zones in CA and Oregon to make white wines is well established.
What 2 properties is sugar split into in side the berry?
What percentage of the grape berry is sugar?
Glucose and frucose
Up to 25% of grape berry contains sugar
Apples and pears contain 12%
Why is the grape better suited to winemaking than any other fruit bearing plant?
The grapevine is the best at
1-accumulating sugar -up to 25% of grape’s juice consists of sugar available for fermentation
2-absorbing profiles from the environment
3-profound adaptability -it is a survivor and a weed
What are the secrets to the grape’s adaptability?
1- Strong root system - store nutrients and anchor the plant - can grow 6 meters deep to reach water
2- Tough and undemanding plant - can adapt to withstand extreme temperatures, poor soil, drought, and can become resistant to frost.
How do grapevines get their energy needed to grow?
They carry a lot of leaves for photosynthesis and catch in in their canopy.
How is sugar produced in plants/grapevines?
Photosynthesis = green plants use sunlight to synthesize sugar from chlorophyll (green pigment), carbon dioxide and water. The byproduct is oxygen.
Why would growing along rivers or lakes improve sugar content?
The water surface reflects and magnifies the light which increases the photosynthesis.
What is the greatest weakness of the vine?
1- Susceptibility to disease and pests - notably Botrytus (gray rot) and phylloxera
This mostly for European vine (American strain were more robust and immune to phylloxera)
2- fertilization and increased yields greatly increases vulnerability of vine
What is Selection Massale?
Peasants and viticulturists in Middle Ages start selecting superior plants of the vineyard and replanting them in similar soil and terroir.
Now growers buy 1 yr old vines from nurseries that get their vines from ‘mother gardens’ planted certified clones of individual varieties which are then grafted onto rootstock.
What comprises a grape cluster?
Stems and grape berry (skin, pulp and seeds)
What is the composition of a grape and what do these elements affect?
SUGAR = determines possible alcohol strength of a wine
ACIDS = affects course of fermentation and flavors
POTASSIUM = (salt) effects microbiological activity and oxidative stability
PHENOLICS = contributes to level of color and tannins
TERPENS = contributes to the flavor profile
•Grape composition is constantly evolving during ripening
What color is red grape must?
White grapes and red grapes all produce white must. Red wine only results when red skins are fermented with the must.
What percentage of a grape is water?
90%
What is must?
Freshly cut grape juice containing skins, seeds and sometimes stems of the fruit
What are the components of a grape?
SUGAR = determines potential alcohol content
ACIDS = fixed acids only (tartaric, Malic, citric)- affects fermentation and flavors
POLYPHENOLS = polyphenols contribute to colors and tannins = anthocyanan/red , flavone/white
TERPENS = contribute to the flavor/aroma profiles
•Grape composition is constantly changing and evolving
What are the components of wine grape skin?
BLOOM = outer waxy layer - resists water loss and stops fungal growth and other infections
PHENOLICS = tannins (polyphenols) + pigments (anthocyanins) + flavors (terpens)
The ________er the skin, the better the flavor and aroma?
Thicker
What are polyphenols?
Molecules of oxygen and hydrogen that polymerize (create elaborate networks of chains of molecules.) The more phenols in a wine , the more complex they become. The older a wine gets, the longer the chains of polyphenols.
Phenols in wine = pigments, tannins and components of taste found in the skin, seeds and stems
Best phenols found in skin (more in red than white)
Most phenols found in seeds, but are not desireable
What are the chemicals in red grapes that provide red, blue, purple color?
What are the chemicals in white grapes that provide lemony, yellow or golden colors?
Anthocyanins
Flavones
What 2 things does the grapevine need above all else to grow?
What else do they need?
Heat to hasten ripening and
Light for photosynthesis
Warm slopes and dry soil - bodies of water to reflect light and produce heat helps
Temperatures are ____er with higher altitudes.
What is the most important thing to consider the higher the altitude?
Lower
The slope is steeper. The steeper the hill, the more efficient the use of sun’s rays.