C5 - The Growing Environment (reviewed) Flashcards
(40 cards)
What can happen to grapes if it is too sunny?
They can become sunburnt, resulting in bitter dark patches on grapes
How should water supply to a vine ideally vary over the growing season?
A good supply early on to support growth, then water stress after veraison to benefit ripening
What is the biological benefit of a grapevine only bearing fruit once it has broken woodland canopy?
Here its fruits would be more visible to animals, ready for propagation
Name the three factors affecting sunlight…
- Seas and Lakes - Vineyards near seas/lakes experience more cloud cover. Sometimes vineyards situated above rivers and lakes can benefit from reflected sunlight.
- Latitude - Day length during the summer season is longer, the further away from the equator a vineyard is. e.g., Germany (Riesling) and Washington State (Cabernet)
- Aspect - Steeper slopes and facing toward the equator increase sunlight
When is the growing season in the Northern/Southern Hemisphere?
- Northern: April - October
- Southern: October - April
List the factors affecting annual temperature…
- Latitude - The further from the equator, the cooler an area is on average. 30 - 50º latitudes satisfy a vine’s need for warmth, but also winter dormancy.
- Altitude - temperature drop 0.6ºC every 100m increase in altitude
- Ocean currents - cool or warm the air above and around them
- Fog - It cools an area. e.g., California and Casablanca in Chile.
- Soil -
- Darker soils or those with a higher stone and rock content absorbs and reradiates the sun’s heat
- High water content soild delay ripening, as it takes more energy to heat the soil and heat from the vines is conducted away more quickly
- Aspect - can affect ripening - the side of a slope facing towards the equator receives more sunlight and heat. e.g., Mosel Valley
Name a rare region with a low continentality, but high diurnal range. Why?
Napa Valley. It’s close to the Pacific, moderating continentality, but experiences on-shore and off-shore breezes and fogs, increasing diurnal range
Name an area where sugar levels will remain low due to cloud cover
Hunter Valley, Australia
What impact can a mild winter have on a vine?
- Can prevent the vine from being dormant, and in the worst cases the vine can produce more than one crop a year, shortening the vine’s life and reducing quality
- It can also allow for larger populations of pests can survive to attack the vines in the following summer
What is the one factor influencing a plant’s growth that does not vary?
CO2
What is a grapevine’s natural habitat?
Woodland, where they would flower and fruit when they broke through the canopy
What effect can summer hail have on a vine? how can growers protect their vines?
- It can damage the grapes and even the vine itself, in worst cases, destroying an entire crop
- Mendoza, Argentina - particularly prone to hail
- Protective measures: netting, aircrafts and rockets
Describe Winter Freeze
- When the temp drops below -20 deg C. This can damage or kill a vine
- The graft callus is the most vunerable part, can be protected by covering up the callus with soil (sometimes the whole vine)
What can be used if rainfall is insufficient? How?
Irrigation
Drip irrigation -
- The most advanced and expensive form of irrigation.
- Each vine has its own dripper that can be computer controlled, ensuring that each vine gets an optimal amount of water.
Sprinklers -
- Cheaper than drip irrigation, but waste a lot of water and create damp conditions like rainfall, increasing disease-risk
Flood irrigation
- Very cheap but only possible in flat or gently sloping vineyards where there is access to large quantities of water (e.g., Chile and Argentina)
In order, what are the temperature definitions laid out by WSET for ‘Cool’, ‘Moderate’, ‘Warm’ and ‘Hot’
Based on average temperature during growing season:
- Cool: 16.5ºc or below
- Moderate: 16.5ºc to 18.5ºc
- Warm: 18.5ºc to 21ºc
- Hot: Above 21ºc
What limits the rate of photosynthesis?
Light levels - the more light, the greater the amount of glucose the leaves produce for growth and grapes
How is water stored in the soil?
By binding with clay particles or humus. It may be accessible in the underlying rock, too.
Describe impact of cooler temperature on vine growth
- Bud burst: happens later
- Flowering and fruitset: can be disrupted leading to lower yields
- During ripening: acid falls less and less sugar is accumulated
-
Shoot and leaf growth:
- Back varieties: will produce wines which are overly astringent and herbaceous (a result of being physiologically unripe)
- White: cope with cooler conditions better because they have no need for ripe tannins and wines are balanced with higher acidity levels
What negative effect can rainfall have?
- Disrupt flowering and fruit set
- Damp conditions after rainfall encourage fungal infection
- Before harvest, berries can swell, diluting flavours in the wines they produce and in extreme cases, berries can split, atracting fungal diseases
What kind of wines do regions with a high vs small diurnal range generally create?
- High diurnal range: Fresher and more aromatic
- Small diurnal range: usually fuller bodied
Describe the vine needs for water…
It helps the vine do the following
- Gives rigidity to shoots and leaves
- Regulates its temperature
- Swells its grapes
Temperature determine amount of water a vine uses
Under water stress conditions, the vine has enough water to photosynthesise, but switches its glucose resources from shoot growth to grape ripening
Water-stressing the vine can also reduce the impact of shading
What can happen during short term drought and where there is too much water during the growing season?
- Short term drought: The vine can temporarily stop transpiration, preserving its resources
-
Too much water: the vines promotes excessive vegetative growth
- This diverts sugars away from the ripening grapes
- The excess of shoots and leaves increases the risk of shading.
Describe the importance of temperatures in wine growing
- Amount of heat in the growing season is the defining factor that determines which grapes can he grown in a given region
- Temperature has an impact on each stage of a vine’s cycle
- Average temperature: between 16ºC and 21ºC degrees C will allow grapes to full
- Above 22ºC degrees - The vine’s cell start to consume more sugar than the vine can produce
- Below 10ºC - too cold for a vine’s cells to function
How is a region’s climate vs. weather defined?
Climate
The annual pattern of temperature, sunlight and rainfall averaged out over several years
Weather
The annual variation that happens relative to the climatic average