Viticulture Flashcards
What is weeping/bleeding?
Vine leaks watery sap from pruned canes.
In the Northern Hemisphere approx what month does weeping/bleeding start?
Typically, February
What is budbreak?
First small shoots and leaves will break through buds left intact by winter pruning.
In the Northern Hemisphere, when does budbreak usually occur?
Once average air temperature surpasses 50 Fahrenheit.
March-April
What is the vine vulnerable to during budbreak?
Frost
What are the small green clusters that form on shoots?
Embryo bunches
When does flowering occur in relation to budbreak?
6-13 weeks–depending on climate
How does the grape vine start the process of fertilization?
It self-pollinates!
After embryo bunches bloom into flowers for ten days it begins the process of fertilizatio.
What is the average fruit set?
30%
What is coulure?
Embryo berries falling from the cluster during fruit set.
What is millerandage?
Some grape flowers fail to fertilize and mature at different rates.
What is verasion?
Ripening.
Sugars are moved from leaf system to the fruit.
Grapes soften and change color.
What is vendange?
Harvest.
What is the preferred annual temperature for the vine?
50-68 Fahrenheit
Ideal–57
What average summer temperature do red grapes prefer?
70 Fahrenheit
What average summer temperature do white grapes prefer?
66 Fahrenheit
What are the ideal bands of latitude for viticulture?
30-50 degrees
What is photosynthesis?
Plants using carbon dioxide into organic compounds
What is the minimum amount of sunshine needed to support viticulture?
1300 hours
What does cloudcover affect?
Amount of heat the sun gives to the vine.
Does not affect photosynthesis
How much rain does the vine require to produce adequate crop?
10-30 inches.
Vine is drought-resistant plant
What is water stress?
Vine receives to little rain.
Promotes smaller berry size and yields, but can lead to interrupted ripening and complete shutdown of the vine.
What does too much rain do to a vine?
Will not adversely affect vine itself
Leads to diluted fruit quality.
Encourages development of fungal diseases.
Define macroclimate
Entire wine region
Napa Valley
Define mesoclimate
Particular vineyard
Define microclimate
Rows or even specific vines
Define continental climate
Strong annual variation in temperature due to lack of proximity to significant bodies of water.
Hotter summers than maritime often with extreme cold winter temperatures
Define maritime climate
Influenced by a large body of water such as a sea or ocean.
Marked by mild temperatures that can fluctuate from year to year, causing vintage variation.
Define Mediterranean climate
Hot and dry summers, aside from immediate coastal areas.
Along coasts, summers are mild due to proxmity to cold water currents, but storms are consequence.
Define high desert
Summers are generally hot and dry.
Daytime temperatures are high, but dramatic drops are often experienced overnight.
What is a diurnal shift?
The difference between average daytime high adn nighttime low temperatures.
This can affect the ripening of grapes and the balancing of acidity and sugar.
What threat does frost pose?
Hazard in spring and fall.
Winter freezing can cause damage if severe and can kill vines.
In spring, frost can damge or freeze and kill delicate buds or flowers, preventing the vine from setting clusters.
What threat does hail pose?
Can shatter grapes on the vine.
What threat do strong winds pose?
Can blow vines over or blow buds and flowers off the vine, preventing grapes from growing.
Cordon trained
The vine has at least one permanent cane that extends from the trunk called an arm/cordon.
Generally require a trellising system
Head trained
No permanent cordon, and trunk ends in knob or head.
Seen as alternative to trellising–can still be done.
Guyot system
Developed in 1860 by Jules Guyot.
Requires vertical trellis on which canes are suspended, and has one spur and one main two year old cane.
