Viticulture Flashcards
Describe six problems of excessive rainfall during the growing season
- Flowering and fruit set rain can cause lack of pollination bringing a lower yield for that year.
- If the vine has too much access to water during the growing season, the vine will continue to grow shoots and leaves during the ripening season. Leaving less sugars for the grapes
- The extra shoots and leaves can cause shading restricting grape ripening
- Waterlogged soils can cause roots to become saturated and die
- Damp conditions that follow rainfall can also encourage the spread of fungal diseases
- Rain shortly before harvest can cause the grapes to plump up and loose concentration of sugars, flavors, and acids leading to an undesirable wine. In extreme cases the grapes can split leading to more fungal disease
Describe the affect of drought on the vine
The vine can temporarily stop transpiration in order to preserve resources and stopping photosynthesis, wilting leaves and the grapes fail to ripen. This can ultimately kill the vine
What are the two problems of cloud cover during the growing season?
Low light levels, can cause problems during flowering and fruit set leading to low yields
Slowing the photosynthesis, can stop grapes from ripening fully
Describe the affect of Sunburn on the vine
This can lead to bitter flavors developing in the grape skins
Describe the affect of winter freeze
A vine can be damaged or killed, especially at the graft union is the most vulnerable
Describe the affect of spring frost
It can kill newly burst buds or shoots reducing the yield and health of the vine
List 3 management techniques for Spring frosts
Heaters
Wind machines
Sprinklers
Describe a management technique for Winter Freeze
“Earthing up”. Where earth or soil can be used to cover up and protect the graft
Describe management technique for Intense sunlight
The grape grower can manage the canopy to ensure enough shade is provided
Describe a management technique for cloud cover
The grape grower can manage the canopy to ensure sunlight is maximized
Describe a management technique for Drought
The grape grower can irrigate the vineyard if local laws permit
Riesling thrives in cold climates, cane two reasons why it can grow in colder conditions
It is very tolerant of winters, buds late so it avoids spring frosts
Describe a maritime climate
Cool to moderate temperatures, low continentality with rainfall evenly spread throughout the year.
What is continentality?
Annual difference between hottest and coldest months
What is Diurnal range?
The difference between hottest and coldest temperatures in a single day
What is Continental climate?
Great difference between hottest and coldest months. Short, dry summers.
What is Mediterranean climate?
Low temperature difference between the hottest and coldest months with warm, dry summers. Low rainfall
What does pruning do?
Pruning is the removal of unwanted leaves, canes, and permanent wood. It shapes the vine and limits its size. This determines the number ad location of the buds what will for shoots in the coming season, impacting future yields. This can have an effect on the distribution of nutrients to the vine, spacing of the buds, which will allow for more even ripening.
What does canopy management do?
Managing the green parts of the vine, which will ensure that grapes can either be protected from extreme heat to better exposed to sunlight.
Why is it important to have grapes brought to the winery cold?
Cold grapes slow down the process of oxidation, which could lead to off flavors
Give one solution to Nematodes in the vineyard
Sanitizing the soil before replanting and using resistant rootstocks have been found to be successful solutions
What are Nematodes and what do they do?
Nematodes are microscopic worms that attack the roots of the vines interfering with water and nutrient uptake. They can transmit viruses.
What conditions encourage Powdery Mildew?
It thrives in warm, humid environments
What is a solution to Powdery Mildew?
Sulfur-based sprays and open vine canopies allow a greater air flow, which promotes evaporation and keeps them dry and possible.
What is head grafting?
The existing vine is cut back to its trunk and a bud or cutting of a new variety is grafted onto the trunk.
What are the advantages of head grafting?
Vine should be able to produce fruit from the new variety at the next vintage, which would take a newly planted wine 3 years. Much cheaper than replanting an entire vineyard.
The Mistral is a hazard in Northern Rhone, how do grape growers combat this?
Supporting the vines with either individual stakes or tee-arrangments of stakes
What is the dominant soil type in the Northern Rhone and why does it help produce premium Syrah?
Granite, it has low fertility so roots can grow deep and strong. Granite absorbs the heat provided and provides good drainage. This allows Syrah grapes to develop concentrated flavors w/out excess water filling the grapes
