D1C03 The Growing Environment Flashcards
1.1.4 Explain how the growing environment influences the vine’s ability to produce and ripen grapes suitable for wine production.
What are important resources needed if the vine is to produce and ripen grapes suitable for making wine.
The amount of warmth, sunlight, water and nutrients and the timing of these key resources within the growth cycle.
What viticultural generic aspect will have a defining influence on the wine produced?
In the vast majority of cases, the growing environment and its effect on natural resources will have a defining influence on the wine produced.
The natural resources available to a particular vineyard or even a particular vine depend on the growing environment. In turn, the growing environment is often a function of the positioning of the vineyard site, which is a key reason why delimited geographical indications are so important throughout the world of wine.
What is the main source of heat and sunlight?
Solar radiation is the main source of both heat and sunlight and therefore many of the factors that influence one also influence the other.
Temperature has a huge influence on vine growth and/or grape ripening in all parts of the vine growth cycle.
Explain the temperature a vine needs in winter….
Cold temperatures (under 10°C) in the winter ensure the dormancy of the vine, however, extreme temperatures (around -20°C) can cause winter freeze and damage the vine.
Temperature has a huge influence on vine growth and/or grape ripening in all parts of the vine growth cycle.
Explain the temperature a vine needs at budburst….
Temperatures above 10°C stimulate budburst, and budburst is often more successful and uniform if there is a significant rise in temperature at this point. Warm soil temperatures can also promote budburst. Cold temperatures that bring frost can be very harmful for buds and new growth and can reduce yields substantially.
Temperature has a huge influence on vine growth and/or grape ripening in all parts of the vine growth cycle.
Explain the temperature a vine needs at shoot growth….
As the new shoots grow and leaves develop, the vine begins to use photosynthesis to create sugar for energy. The optimum temperature range for photosynthesis is approximately 18–33°C, and hence temperature is not usually a limiting factor at this time.
Temperature has a huge influence on vine growth and/or grape ripening in all parts of the vine growth cycle.
Explain the temperature a vine needs at flowering….
Warm temperatures promote successful, uniform flowering (optimum above 17°C) and fruit set (optimum range 26–32°C), whereas cold, damp conditions can cause problems for flowering and fruit set and therefore reductions in yield and potentially quality of the grapes and wine.
Temperature has a huge influence on vine growth and/or grape ripening in all parts of the vine growth cycle.
Explain the temperature a vine needs at bud development….
Warm temperatures at this time also promote increased bud fruitfulness (above 25°C is best) in the next year, and therefore affects yields in the next growing season.
Temperature has a huge influence on vine growth and/or grape ripening in all parts of the vine growth cycle.
Explain the temperature a vine needs at grape ripening….
Temperature also has an influence on many aspects of grape ripening:
- Sugar accumulation in the grapes is generally faster at warm temperatures due both optimum rates of photosynthesis producing sugars and because increased grape transpiration promotes the movement of sugar into the grape.
- Malic acid degradation is also increased at warm temperatures.
- The effect of temperature on the formation of aroma precursors and aroma compounds is very complex; generally riper aroma/flavours are associated with grapes grown in warmer climates.
- Cool conditions may hinder the breakdown of methoxypyrazines, which can give herbaceous aromas.
- In black grapes, anthocyanin synthesis is optimum at 15–25°C (and therefore the development of colour). Tannin synthesis possibly follows the same pattern, but more research is needed.
Temperature has a huge influence on vine growth and/or grape ripening in all parts of the vine growth cycle.
Explain the effects of extreme heat during grape ripening…
Extreme heat, especially when paired with dry conditions, can cause photosynthesis to slow or stop, slowing vine growth and grape ripening. This is due to the heat sensitivity of enzymes that catalyse photosynthesis.
In addition, water stress, which is typical in many hot regions, can also cause photosynthesis to slow down or stop due to the shutting of stomata to prevent water loss (see The Effects of Water). The closed stomata limit intake of carbon dioxide, which is needed for photosynthesis.
What can lead to the rapid loss of acidity?
in the final month of ripening mean temperatures above 21 Ccan lead to a rapid loss of acidity,
whereas mean temperatures below 15 C can reduce acid loss to a point that acidity levels in the must are too high.
How do temperature needs differ for different varieties?
Different grape varieties have different needs and sensitivities regarding temperature.
Late-ripening varieties may need a greater amount of heat through the growing season to ripen sufficiently (both in terms of sugar accumulation and also aroma and tannin ripeness). Early-ripening varieties, such as Pinot Noir and Chardonnay, will need less heat in total and will ripen very early in warm climates.
When becomes sunlight the limiting factor for photosynthesis?
Full sunshine (intense sunlight, not blocked by cloud) is not required, and generally amount of light only becomes the limiting factor to rate of photosynthesis if light levels drop below one third of full sunshine.
Hence, fog can slow photosynthesis but an average cloudy day will not.
Grape exposure to sunshine has a number of effects, what are these (positive) effects of sunshine on the vine?
- enhancing the development of anthocyanins (colour pigments) in black grapes and the reduction of methoxypyrazines.
- Sunshine on the grapes leads to greater accumulation of tannins pre-véraison and promotes tannins polymerisation after véraison, and therefore less bitterness.
- It is also associated with increased levels of some favourable aroma precursors and aroma compounds.
- Sunshine also warms the grapes and because of this increases the rate at which malic acid is used up in grape respiration, leading to lower acidity levels.
What class of aroma compounds is responsible for many of the fruity and floral aromas in wines?
Terpenes are responsible for many of the fruity and floral aromas in wines, such as the grapey aromas found in Muscat.
What could be the effect of prolonged periods of sunshine and hot temperatures?
Prolonged periods of sunshine and hot temperatures can lead to sunburn on sun-exposed grapes, which has a negative effect on grape quality and yields
What can be beneficial in climates that are warm or hot and/or very sunny?
In climates that are warm or hot and/or very sunny, some shading of the fruit is usually beneficial.
The grape grower may ensure the grapes are covered with one thin layer of leaves, so that the bunches receive dappled sunshine.
Grape vine exposure to sunshine has a number of effects, explain the sunshine a vine needs late spring / early summer
Sunshine in late spring / early summer is associated with successful fruit set and the exposure of compound buds to sunshine promotes bud fruitfulness in next year’s growing season.
What is the effect of latitude on solar radiation?
Regions nearer the Equator - having a lower latitude - receive more intense solar radiation and receive more per annum than those nearer the poles.
What are examples of low latitude areas under vine?
Mendoza, South Africa, New South Wales
Higher latitude areas, e.g. nearer the Poles, are northern France and Germany.
Explain the effect of latitude on solar radiation…
Solar radiation is adsorbed (held by water droplets, dust and ozone) and scattered as it travels through the Earth’s atmosphere, decreasing its intensity.
The curvature of the Earth means that nearer the poles solar radiation must travel through a larger section of atmosphere to reach the Earths surface. It also means that the radiation hits the Earth at a low angle, so the radiation is spread over a larger area (it is more diffuse).
By contrast, at the Equator the radiation travels through a smaller section of atmosphere and hits the Earths surface at a larger angle (nearer perpendicular), so that solar radiation here is more powerful.
What are the effects of lower lattitudes on the grapes grown there?
If all other factors were equal, temperatures would be warmer and sunshine more intense in regions at lower latitudes than those at higher latitudes.
Very broadly speaking, this means that grapes grown at lower latitudes can have higher levels of sugar, lower levels of acidity, riper aromas and, in black grapes, higher but riper tannins and more colour intensity than those at higher latitudes.
What helps grapegrowing in high latitude regions, despite the low temperatures?
High latitude regions have longer daylight hours in the summer and shorter daylight hours in the winter. This permits a longer duration of time over which photosynthesis can take place in the growing season. Given the cooler temperatures in these locations, this can be useful in helping the vine to produce enough sugar for ripening grapes.
Low latitude regions receive similar daylight hours (and hence heat and sunlight) throughout all seasons of the year.
Between what latitudes can grapes in generally grow?
It is generally said that grapes for wine production can grow between 30 and 50 degrees latitude on each side of the Equator. There are exceptions to this.
However, regions nearer the Equator are usually too hot during the day. Vines transpire to regulate their temperature and if water is not readily available, this can cause water stress. Grapes can also suffer from sunburn. Regions near the poles are simply not warm enough during the growing season (despite long daylight hours) for enough sugar to accumulate in the grapes.
What is the effect of altitude on temperature?
Temperature falls by approximately 0.6 C over every 100 m increase in altitude.
High-altitude sites can therefore be favourable in areas of low latitude that would otherwise be too hot. There are vineyards in Salta (a low latitude region) planted at up to approximately 3000 m above sea level, and here grapes may struggle to ripen sufficiently every year.
By comparison, many of the best vineyard sites in high latitude areas, such as Burgundy and Loire Valley, are at relatively low altitudes, as otherwise temperatures would be too low for sufficient ripening.
What is the effect of high altitudes on sunshine? And what is the effect on grape berry development?
Sunshine is more intense at high altitudes than low altitudes because the solar radiation travels through less atmosphere before it reaches these sites. Ultraviolet radiation, (radiation with a lower wavelength than visible sunlight) is also greater at higher altitudes. Both of these factors are thought to promote anthocyanin and tannin synthesis.
What is the effect of altitude on the diurnal range?
High-altitude sites often have a high diurnal range (the difference between day and night temperatures).
The ground absorbs energy from solar radiation during the day and releases energy into the atmosphere during the night. At lower altitudes the air in the atmosphere (particularly the water vapour) absorbs some of this energy, meaning some heat is retained at night. At high altitudes the air is thinner and holds less moisture and therefore heat rapidly escapes, leading to relatively cool night-time temperatures.
In warm climates, high diurnal range can be beneficial for the retention of acidity during grape ripening.
Define diurnal range?
The diurnal range of a region or vineyard site is the average difference between day-time and night-time temperatures.
Regions with continental climates or at high altitude tend to have higher diurnal ranges (larger difference between day and night temperatures), whereas regions near a large body of water tend to have lower diurnal ranges (smaller difference between day and night temperatures).
What is the effect of a large diurnal range in warm or hot climates?
In warm or hot climates, such as those found in Mendoza or Ribera del Duero, a large diurnal range is often thought to be favourable. In these climates, a relatively cool period during the night can slow the respiration of malic acid and be beneficial for the formation of anthocyanins (day-time temperatures are too hot).
What is the effect of a low diurnal range in cool or moderate climates?
In cool and moderate climates, such as Mornington Peninsula or Mosel, a low diurnal range may be favourable so that night-time temperatures still allow ripening (e.g. acid degradation, anthocyanin synthesis) to continue, which may be needed for grapes to ripen sufficiently.
It is also thought that night-time temperatures can have some influence on aroma compounds. For example, warmer night temperatures are associated with a greater breakdown of methoxypyrazines, which may be important in cool climates, and cooler temperatures are associated with a greater retention of some other compounds, such as rotundone. Given the number of aroma compounds and precursors in grapes and their interactions such relationships are complex.
What is aspect?
The particular direction that vineyards planted on slopes will face.
What is the impact of latitude on the importance of aspect?
The importance of aspect and the steepness of the slope increases at high latitudes. This is because solar radiation hits the Earth at a low angle at high latitudes.
In the context of the vine growth cycle, the angle is lowest in the spring and autumn (compared to the summer). The slope compensates the earths curveture, increases the angle (nearer to perpendicular) at which the solar radiation hits the Earth’s surface, hence increasing the intensity of heat and light.
The amount of warmth is also often a limiting factor in high latitude areas, so a slope can make a marked difference on the viability of a vineyard, what grape varieties that can be grown there and the ripeness of those grapes. Extra warmth and light during spring and autumn extend the viable growing season for vines grown on slopes that face towards the sun.
As evidence of this, in the cool climate regions of Burgundy and Alsace, the Grand Cru sites giving wines with greater ripeness and concentration are usually positioned on south-east facing slopes, while the vineyards of the generic appellation are found on the flat.
How can grapegrowers benefit from aspect in warm climates?
In warm climates, it may be desirable to limit the amount of heat and light. Planting on slopes that face away from the sun throughout most of the day can help achieve this. This may allow the grape grower to grow earlier-ripening grape varieties or produce wines with less alcohol and more acidity than would otherwise be the case at that latitude. For example, in Stellenbosch, white grape varieties are sometimes planted on south-facing slopes so that the grapes retain refreshing acidity.
What is the impact of east facing slopes on grapegrowing?
Slopes facing east benefit from morning sunshine that can heat up the atmosphere when air and soil temperatures are at their lowest. This can extend the hours of vine growth and grape ripening each day, especially in cool climates. The grape canopy, which can be covered with dew in the morning, also dries out earlier in east-facing vineyards, reducing the spread of fungal disease, which is beneficial for grape quality and yields.
Slopes that face west receive the afternoon sun and may become too hot, especially in warm climates, and risk of sunburnt grapes is increased (see Sunburn in Hazards). However, in areas with coasts to the west, e.g. California and Western Australia, cool afternoon sea breezes may alleviate this.
What are benefits of grapegrowing on slopes?
Slopes can provide additional benefits, including shallower, poorer soils and better drainage.
Slopes can also provide shelter from winds and rain, and protection from frosts (air movement down the slope prevents frosts from forming).
However, soil erosion and inability to use machinery on steep slopes can be problematic.
Explain the effect of proximity to water on local a/o microclimate.
Large bodies of water, such as lakes and seas, can have a significant impact on nearby vineyards. This is because water heats up and cools down more slowly than dry land. During the day, the water and the air above a body of water remains relatively cool, and lowers the average daytime temperature in the local area. Air directly above dry land heats up more quickly than that above the water, and this warm air rises. Cool air from above the water is drawn to the land to replace the warm air as it rises, resulting in cool, humid afternoon breezes.
The opposite happens at night. The water retains the warmth gained during the day, whereas, without solar radiation, the land loses heat relatively quickly. The warmth of the body of water keeps the local area warmer, e.g. a higher nighttime temperature. The same effect can be experienced over the year, with large bodies of water giving cooler summers and milder winters.
How does proximity to water effects grapegrowing in the Finger Lakes, New York?
In the Finger Lakes in New York, close proximity to the lakes reduces the severity of winter freeze, which would damage or even kill the vines. The movement of air also helps to protect against spring frosts that could reduce yields.
How does proximity to water effects grapegrowing in Carneros, California?
In Carneros, California, the proximity to the San Pablo Bay means that early-ripening grape varieties Chardonnay and Pinot Noir can be grown here (for still and sparkling wine), benefitting from cooling breezes, whereas later-ripening grape varieties such as Cabernet Sauvignon need to be grown further inland where warm afternoons help ripen the grapes.
What ocean current influences grapegrowing in Bordeaux?
Gulf Stream, The warmer climate in Bordeaux (average growing season temperature 17.7°C) is at least partially due to the Gulf Stream, which flows from the Gulf of Mexico and warms many European wine regions.
What ocean current influences grapegrowing at the west coast of North America?
California current, The west coast of North America, including Oregon, is cooled by the cold California current, which flows from the northern Pacific (average growing season temperature in Willamette Valley is 15.9°C). In the western USA, wine regions that are sheltered from the ocean influence, for example by mountain ranges, are much warmer and drier than those that are not.
Both the Willamette Valley in Oregon and Margaux in Bordeaux are located at approximately 45° latitude. Why do these areas grow different ripening varieties?
Due to the effect of ocean currents on these areas: The main grape in the Willamette is early-ripening Pinot Noir, whereas Margaux is capable of growing late-ripening Cabernet Sauvignon.
How does latitude effect the amount of radiation from bodies of water?
Vineyards located in very close proximity to large bodies of water can benefit from radiation reflected from the water surface. The amount of radiation reflected depends on the angle at which the solar radiation hits the water and is greatest at high latitudes. Reflected sunshine is advantageous in cool climates that have limited sunshine (very cloudy conditions).
What is ENSO?
El Niño-Southern Oscillation (ENSO) is a climatic cycle in the Pacific Ocean that has a significant effect on weather patterns. It has two opposite phases, El Niño and La Niña.
What effect has El Niño in what areas of the world?
El Niño starts when warm water in the western Pacific Ocean moves eastwards along the Equator towards the Caribbean. The eastern Pacific Ocean becomes warmer than average and this tends to cause high levels of rainfall and risk of hurricanes in South America and California. Any hurricanes clearly have a destructive influence. The rainfall can disrupt pollination and fruit set and lead to excessive water availability, which can increase vegetative growth and hinder ripening. However, El Niño brings warmer than average temperatures and drier conditions in the Pacific Northwest (Washington and Oregon). On the western side of the Pacific Ocean in Australia, El Niño tends to cause warmer temperatures and drought conditions, which can cause extreme vine stress and vine damage. El Niño events typically occur once every 3–7 years, with extreme El Niño events being rarer. It is thought, however, that these extreme events are becoming more frequent as a part of climate change.
What effect has La Niña in what areas of the world?
La Niña is caused when the eastern Pacific Ocean is cooler than average. It tends to result in cooler, wetter conditions in the Pacific Northwest, but warmer, drier conditions in California and South America. La Niña also causes wetter and cooler conditions in Australia.
What is the effect of winds and breezes on the growing environment?
Winds and breezes can have a warming or cooling influence in many wine regions. Areas near to a body of water may experience cool breezes during the day, moderating the diurnal range of such regions. Winds that have travelled over hot land masses can bring warm air that heats the vineyard area.
How do valley influence the effects of winds a/o breezes?
Valleys that face the coast or other areas of low land can mean that winds are felt even relatively far inland. Valleys can also lead to stronger winds as the moving air is funnelled.
Name some areas that are influenced by winds a/o breezes?
the Petaluma Gap in California (wind taken far inland), the Zonda in Mendoza (warm air).
How can wind help to counter fungal diseases?
As well as influencing temperature, winds and breezes reduce the occurrence of humid, stagnant air in the vine canopy that encourages the development of fungal diseases.
How can wind lead to water stressed vines?
Winds increase evapotranspiration rates in the vine, meaning that the vines’ water needs may be higher than in non-windy areas. If water isn’t readily available, for example through irrigation, this can lead the vine to become water stressed.
What effect can strong winds have on vineyards; and what is done to mitigate this?
Strong winds can cause damage to vines and vineyard trellising, resulting in lower yields and higher equipment and labour costs. Rows of trees can be planted at the edges of vineyards to act as windbreaks; however, care must be taken as they can compete with the nearest vines for water and nutrients. Fences can also be used, but are less aesthetic and require maintenance.
Soil can have an important effect on temperature. What characteristics of soil are into play here?
The drainage of the soil, its structure and colour all influence the warmth of the soil and the air above the soil.
What is the effect of free draining soils on grapegrowing?
Soils that drain freely, warm up more quickly in the spring than damp soils. Rising soil temperature encourages the breakdown of starch in the roots, which stimulates budburst and shoot growth. Therefore, it is desirable for cool-climate vineyard areas to have free-draining soils to promote early budburst, and hence potentially a longer growing season within which to get the grapes ripe. However, early budburst does increase the risk of harmful spring frosts damaging young buds and shoots.
What is the effect of warm soils on water and nutrient availability?
Warm soils encourage root growth, which means the vine can absorb more water and nutrients.
Name 2 examples of freely draining soils?
(For example) sandy or stony soils
How do light-coloured soils effect grapegrowing?
Light-coloured soils reflect some energy from solar radiation. Extra light energy into the lower parts of the canopy that may receive less sunlight from above can be beneficial to increase photosynthesis and grape ripening in cool and cloudy climates or where late-ripening grapes are used. However, in warm climates this may increase temperatures in the warmest parts of the day.
Name an example of light-coloured soil and where it is found?
Soils rich in chalk as found in Sancerre and Champagne
How do dark-coloured soils effect grapegrowing?
Dark-coloured soils absorb more energy and re-radiate most of it when temperatures are cooler, for example at night. This can be useful, especially in cool climates or for late-ripening grapes, allowing the development of colour and degradation of acid to continue during the night.
Name an example of dark-coloured soil and where it is found?
Soils from volcanic origin as found in Etna
How do stony soils effect grapegrowing?
Stony soils, especially if the underlying soil is slightly damp, are also very effective at absorbing heat and releasing it at night. This is because stone and water are good conductors compared to air.
How is mist formed?
Mists are formed by tiny drops of water collecting in the air just above an area of ground or water. They are usually formed when warm air is rapidly cooled, causing water vapour in the air to condense. This may occur, for example, at night when warm air over a body of water meets cooler conditions above the land. Dense mist is called fog.
Name a few examples of winegrowing areas influenced by mist and fog
Mist and fog can form in different vineyard regions at different times of the day, although morning is the most common time, such as in parts of Sonoma, Napa, Leyda Valley and Sauternes, among other regions.
What are the effects of mist, fog or (substantial) cloud cover on grapegrowing?
Depending on the density of the mist, fog or amount of cloud cover, sunlight can be limited to the extent that photosynthesis is reduced. As sunlight is reduced this also means that temperatures can be lower, particularly if morning fog or cloud delays the time at which the morning sun begins to warm the land. Where mists, fogs and cloudy conditions are regular, this can slow down sugar accumulation and acid degradation in the grapes, which may be beneficial in warm regions or when growing early-ripening grape varieties. As mists and fogs are made up from water droplets and occur at ground level they can also increase humidity in the vineyard and therefore the occurrence of fungal disease or, in areas with dry, sunny afternoons, noble rot.
What does a vine needs water for?
The vine needs water for turgidity (so that it doesn’t wilt), photosynthesis and regulating its temperature. Water also acts as a solvent for nutrients in the soil, which is important for their uptake by the vine, and is the medium in which all of the vine’s biochemical and physiological mechanisms take place.