KA introduksjon Flashcards
Dormacy
When is the grapevine dormant?
Dormacy (no: dvale)
November to March (N. Hemisphere)
May to September (S. Hemisphere)
Dormacy
What occurs during the dormancy period of grapevines?
- Shoots become lignified (turn from green to brown branches)
- Vines are pruned (balanced growth the following season)
Dormacy
What temperature is required for grapevines to remain dormant?
Below 10°C.
Average daily temperature
Growing season
What happens during the bud break stage in grapevines?
Bud break (no: knopping)
Buds swell and burst open, and shoots begin to grow.
Growing season
When does bud break typically occur in the Northern Hemisphere?
Bud break (no: knopping)
Between March and April.
Temperatures below 0 degrees C, will kill the buds.
Growing season
What is the main factor that drives the shoot growth stage?
Carbohydrate reserves from the vine’s trunk and roots.
When the leaves reach 2/3 of their size, they produce enough energy to further growth.
Growing season
What is critical for successful pollination during the flowering stage?
Stable temperatures and adequate sunlight.
Rain and wet weather may cause poor pollination.
What is Millerandage and what causes it?
A condition where grape clusters have berries of varying sizes and maturity levels, caused by poor weather conditions during flowering.
The vine produce small, seedless, grapes.
What happens during the veraison stage of grapevine development?
Grapes change color and begin to ripen.
What environmental condition is preferred during the ripening stage?
Dry weather to encourage grape maturation.
When does the harvest period typically occur in the Northern Hemisphere?
September to October.
What are the three key elements monitored before harvesting grapes?
Sugar levels, aroma development, and tannin maturity.
What is the function of removing leaf canopies before harvest?
To give grapes direct sun exposure for additional ripening.
Why is rain undesirable just before the grape harvest?
It can cause grapes to swell, burst, and develop rot.
What is the term for adjusting the grape yield by removing some grape clusters?
Green harvest.
How are sugar levels in grapes measured in vineyards?
Using a refractometer.
What is the importance of phenolic ripeness in grape harvesting?
It ensures tannins and aromas in the grapes are mature.
How can the winemaker adjust wine if the balance between phenolic and physiological ripeness is not perfect?
By adjusting acidity and sugar levels during winemaking.
What are the two methods of harvesting grapes?
Hand-harvesting and machine harvesting.
What is the annual sequence for a vine?
- Winter/early spring (dormancy, budding)
- Spring (growth season)
- Late spring (flowering, pollination)
- Summer (ripening/Veraison)
- Fall (harvest)
Explain Coloure
Cloudy, cold, or wet weather during flowering leads to poor pollination. Rain during flowering washes away the pollen, resulting in poorer fertilization and lower yields. If the flower is not fertilized by pollen, it does not develop into grapes but falls off.
