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.

1
Q

What are important resources needed if the vine is to produce and ripen grapes suitable for making wine.

A

The amount of warmth, sunlight, water and nutrients and the timing of these key resources within the growth cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What viticultural generic aspect will have a defining influence on the wine produced?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the main source of heat and sunlight?

A

Solar radiation is the main source of both heat and sunlight and therefore many of the factors that influence one also influence the other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

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….

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

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….

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

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….

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

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….

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

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….

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

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….

A

Temperature also has an influence on many aspects of grape ripening:

  1. 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.
  2. Malic acid degradation is also increased at warm temperatures.
  3. 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.
  4. Cool conditions may hinder the breakdown of methoxypyrazines, which can give herbaceous aromas.
  5. 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.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

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…

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What can lead to the rapid loss of acidity?

A

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 well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do temperature needs differ for different varieties?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When becomes sunlight the limiting factor for photosynthesis?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Grape exposure to sunshine has a number of effects, what are these (positive) effects of sunshine on the vine?

A
  1. enhancing the development of anthocyanins (colour pigments) in black grapes and the reduction of methoxypyrazines.
  2. Sunshine on the grapes leads to greater accumulation of tannins pre-véraison and promotes tannins polymerisation after véraison, and therefore less bitterness.
  3. It is also associated with increased levels of some favourable aroma precursors and aroma compounds.
  4. 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.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What class of aroma compounds is responsible for many of the fruity and floral aromas in wines?

A

Terpenes are responsible for many of the fruity and floral aromas in wines, such as the grapey aromas found in Muscat.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What could be the effect of prolonged periods of sunshine and hot temperatures?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What can be beneficial in climates that are warm or hot and/or very sunny?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Grape vine exposure to sunshine has a number of effects, explain the sunshine a vine needs late spring / early summer

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the effect of latitude on solar radiation?

A

Regions nearer the Equator - having a lower latitude - receive more intense solar radiation and receive more per annum than those nearer the poles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are examples of low latitude areas under vine?

A

Mendoza, South Africa, New South Wales

Higher latitude areas, e.g. nearer the Poles, are northern France and Germany.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Explain the effect of latitude on solar radiation…

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the effects of lower lattitudes on the grapes grown there?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What helps grapegrowing in high latitude regions, despite the low temperatures?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Between what latitudes can grapes in generally grow?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the effect of altitude on temperature?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the effect of high altitudes on sunshine? And what is the effect on grape berry development?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the effect of altitude on the diurnal range?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Define diurnal range?

A

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).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the effect of a large diurnal range in warm or hot climates?

A

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).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the effect of a low diurnal range in cool or moderate climates?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is aspect?

A

The particular direction that vineyards planted on slopes will face.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the impact of latitude on the importance of aspect?

A

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 well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How can grapegrowers benefit from aspect in warm climates?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the impact of east facing slopes on grapegrowing?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are benefits of grapegrowing on slopes?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Explain the effect of proximity to water on local a/o microclimate.

A

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 well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How does proximity to water effects grapegrowing in the Finger Lakes, New York?

A

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 well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How does proximity to water effects grapegrowing in Carneros, California?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What ocean current influences grapegrowing in Bordeaux?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What ocean current influences grapegrowing at the west coast of North America?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Both the Willamette Valley in Oregon and Margaux in Bordeaux are located at approximately 45° latitude. Why do these areas grow different ripening varieties?

A

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 well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

How does latitude effect the amount of radiation from bodies of water?

A

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).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is ENSO?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What effect has El Niño in what areas of the world?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What effect has La Niña in what areas of the world?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is the effect of winds and breezes on the growing environment?

A

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 well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

How do valley influence the effects of winds a/o breezes?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Name some areas that are influenced by winds a/o breezes?

A

the Petaluma Gap in California (wind taken far inland), the Zonda in Mendoza (warm air).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

How can wind help to counter fungal diseases?

A

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 well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

How can wind lead to water stressed vines?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What effect can strong winds have on vineyards; and what is done to mitigate this?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Soil can have an important effect on temperature. What characteristics of soil are into play here?

A

The drainage of the soil, its structure and colour all influence the warmth of the soil and the air above the soil.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is the effect of free draining soils on grapegrowing?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What is the effect of warm soils on water and nutrient availability?

A

Warm soils encourage root growth, which means the vine can absorb more water and nutrients.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Name 2 examples of freely draining soils?

A

(For example) sandy or stony soils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

How do light-coloured soils effect grapegrowing?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Name an example of light-coloured soil and where it is found?

A

Soils rich in chalk as found in Sancerre and Champagne

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

How do dark-coloured soils effect grapegrowing?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Name an example of dark-coloured soil and where it is found?

A

Soils from volcanic origin as found in Etna

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

How do stony soils effect grapegrowing?

A

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 well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

How is mist formed?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Name a few examples of winegrowing areas influenced by mist and fog

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What are the effects of mist, fog or (substantial) cloud cover on grapegrowing?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What does a vine needs water for?

A

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.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

The vine needs water to survive and adequate water availability is vital for healthy vine growth and grape ripening. What is the minimum rainfall per year a vine needs to survive?

A

Generally, the vine needs a minimum of 500 mm of rainfall per year in cool climates and at least 750 mm in warm regions. Either too little or too much water can have a negative influence.

66
Q

What are stomata?

A

The stomata are tiny pores on the underside of vine leaves that allow the free exchange of water vapour out of the vine, and also let carbon dioxide and oxygen diffuse in and out of the leaves.

67
Q

Explain transpiration…

A

The loss of water from the cells in the leaf through the stomata causes water to be pulled upwards from the soil, through the roots and the above-ground parts of the vine. This is called transpiration.

68
Q

What is the effect of lack of water on the vine? And what does it cause in extreme cases?

A

If the vine has sufficient water, it can keep its stomata open all day. A lack of water causes the vine to partially close its stomata. This can help conserve water, but also reduces or even stops photosynthesis due to lack of carbon dioxide entering the leaves. As photosynthesis is the way that the plant makes sugars for energy, this causes the vine’s growth to be stunted and ripening to slow down. Extreme cases of water stress can lead to leaf loss and vine death.

69
Q

Name some winegrowing areas where lack of rainfall is an issue…

A

Lack of rainfall in the growing season can be an issue in several wine regions, including many of those within Argentina, California, South Africa and Australia. In many of these regions, irrigation is needed for viticulture to be possible.

70
Q

What is the water need of vines in the (early) spring?

A

A plentiful supply of water in the spring encourages the growth of lots of leaves and hence the establishment of a large leaf surface area to support the growth of the vine and ripening of grapes.

71
Q

What is the water need of vines in late spring and early summer?

A

It is thought that mild water stress before véraison is beneficial as it inhibits further vegetative growth.

72
Q

What is the effect of water being too easily available in the growing season?

A

If water is too easily available into late spring and early summer, vegetative growth is promoted and prolonged into the period of grape ripening, which acts as a competitive source for the vine’s sugars, delaying and compromising ripening.

73
Q

What is vegetative growth?

A

Growth of shoots and leaves, e.g. all green, non-reproductive parts of the vine.

74
Q

What is the effect of excessive vegetative growth?

A

An excessive amount of shoots and leaves in the canopy can cause excessive shading of the grape bunches. Unless this is adequately controlled this can lead to reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher levels of methoxypyrazines. Dense canopies of shoots and leaves also have poor ventilation, which can lead to fungal disease in rainy or humid climates.

75
Q

What is the water need of vines between véraison and ripening?

A

The optimum amount of water required by the vine between véraison and ripening is not conclusive. However, it is widely agreed that severe water stress or plentiful water (that could restart vegetative growth or be taken up into the grapes) is not favourable. Too much water available late in the ripening period can cause dilution of sugars in the grapes and even grape splitting, which in turn encourages botrytis. By comparison, a water deficit late in ripening may lead to grape shrivel and the grapes may not reach the desired level of ripeness.

76
Q

What is the effect of damp soils on grapegrowing?

A

Damp soils are often cold, especially early in the growing season, and can delay budburst, which can shorten the growing season.

77
Q

What is the effect of warm soils on grapegrowing?

A

Warm soils promote budburst and also encourage root growth and therefore the ability for the vine to take up water and nutrients.

78
Q

What is the effect of hail on grapegrowing?

A

Hail can cause major damage to green parts of the vine at any point in the growing season, leading to lower yields and potentially reduced quality of the remaining fruit.

79
Q

What effect can rainfall at pollination and fruit set have?

A

Rainfall at pollination and fruit set can negatively affect these important stages of the vine growth cycle (although water stress can also), resulting in uneven ripening or lower yields.

80
Q

What is the effect of excessive rain on grapegrowing?

A

Rain often creates a humid environment in the vine canopy that can then lead to fungal diseases such as powdery mildew and botrytis.

81
Q

What is the effect of dry air on grapegrowing?

A

Air that is low in humidity can increase evapotranspiration and therefore potential of water stress. It is also associated with increased grape transpiration and hence higher sugar accumulation in the grapes.

82
Q

What are the effect of the presence of a large body of water on grapegrowing?

A

The presence of a large body of water can moderate both diurnal and seasonal temperatures. Ocean currents can also either increase or decrease the average temperature in the growing season of nearby wine regions. A lake or river can encourage breezes that may reduce likelihood of frost. However, proximity to water can also increase the level of humidity in the vineyard, which can encourage fungal disease; note that many of the vineyard areas famous for botrytised sweet wines are near bodies of water, such as Sauternes, Tokaj and Mosel.

83
Q

Explain how rainfall is caused?

A

Rainfall is caused by water vapour condensing and precipitating. Warm temperatures cause moisture from the land to evaporate rise. As the warm moist air rises in the atmosphere, it cools and condenses into clouds and eventually rain. Snow and hail are other forms of precipitation and can also be natural sources of water when they melt.

84
Q

How does topography influence patterns of rainfall?

A

Mountain ranges can force winds of warm moist air upwards over high altitudes. This causes the water vapour to cool, condense and precipitate. This can mean that the regions on one side of the mountain experience greater rainfall, whereas regions on the other side are sheltered from the rain-bearing winds and often have very dry conditions (these regions are located in a ‘rain shadow’).

85
Q

Name a wine region effected by a ‘rain shadow’…

A

The wine regions of Washington State are an example of this effect. On the west of the Cascade Mountains the AVA of Puget Sound is cooler and much wetter than the warmer, drier AVAs to the east of the mountains, for example Columbia Valley. Plentiful rainfall in the winter and early spring mean that grape growers in Puget Sound can dry farm (apply no irrigation) whereas irrigation is needed in Columbia Valley for vines to survive.

86
Q

Name the 3 soil characteristics that have a significant influence on the water availability to the vine’s roots?

A

The amount of water available to the vine depends on how easily the water drains, the water-holding properties of the soil, being a function of: (1) the soil’s texture and (2) organic matter content and (3) the soil depth.

87
Q

What is albariza, where is it found and how does it help winegrowing?

A

In Jerez in Spain the main soil type is albariza, a clay soil that has good water retention and which releases water slowly to the vines. This soil also forms a crust when dry reducing evaporation. That is why Jerez, receiving 650 mm with virtually no rainfall in the summer months, is able to sustain viticulture.

88
Q

Name an area with high annual rainfall that still requires some irrigation. And why is this?

A

Hawkes Bay in New Zealand receives around 800 mm rainfall annually, however, the extremely free draining nature of the gravel soils in the area mean that irrigation is sometimes required.

89
Q

Explain how water-logged soils effect grapegrowing.

A

Water-logged soils (usually as a result of poor drainage) are harmful to the vine, reducing the amount of oxygen available to the roots, which slows their growth and eventually killing the vine.

90
Q

How does topography influence water availability?

A

There will be greater surface run-off in vineyards on slopes. This can mean there is less penetration of water into the soil and therefore less water available to vine roots. This may be advantageous in regions with high rainfall. However, the surface run-off causes erosion of the soil and leaching of nutrients and these issues need to be factored into vineyard management. Due to erosion (even without surface run-off, the soil on slopes generally gradually falls down the slope), soils on slopes are generally thin, limiting the area over which vines can obtain water and nutrients.

91
Q

What is evapotranspiration (rate)?

A

Evapotranspiration rate is the amount of transpiration from the vine, combined with the evaporation of water from the soil surface. It is, hence, the rate at which water is no longer available, either because it has been taken up by the vine or because it has been lost to the atmosphere (e.g. evaporation from the soil surface).

92
Q

What influences the evapotranspiration rate?

A

Evapotranspiration rate depends on the temperature, humidity and wind, with hot, dry, windy weather (such as that in Mendoza and Patagonia) leading to faster rates.

93
Q

What is the effect of a high evapotranspiration rate?

A

A high evapotranspiration rate means that more water is needed to satisfy the vine’s requirements than at a low evapotranspiration rate. Therefore, vines in hot, dry, windy conditions need more water than vines in cool and humid conditions. However, regions with hot and dry conditions are often those with least rainfall, and therefore irrigation may be needed to meet the vine’s needs.

94
Q

Vines require low levels of nutrients and therefore most soils are able to sustain vine growth. Why is it still important for the grape grower to monitor nutrient levels for deficiencies?

A

Soil nutrients are depleted by viticulture and therefore it is important for the grape grower to monitor nutrient levels for deficiencies. The vine acquires the nutrients it needs from the soil. Nutrients are important for healthy vine growth and can have an influence on yield and grape composition.

95
Q

What are the most important nutrients in vine growth and reproduction?

A

The most important nutrients are: Nitrogen, Potassium, Phosphorus, Calcium and Magnesium. Several other nutrients play a role in vine growth and reproduction. These include sulfur, manganese, boron, copper, iron and zinc.

96
Q

Explain the role the following important nutrient plays in vine growth and reproduction: NITROGEN.

A

Nitrogen is a component of proteins and chlorophyll (required for photosynthesis). Too much nitrogen in the soil causes excessive vegetative growth, with sugars being diverted to the growing shoots and leaves rather than the grapes, hindering ripening. Too little nitrogen results in reduced vigour and yellowing of vine leaves. Grapes that have low nitrogen levels can also be problematic for fermentation. Overall, vines with a restricted supply of nitrogen tend to produce higher quality grapes.

97
Q

Explain the role the following important nutrient plays in vine growth and reproduction: POTASSIUM.

A

Potassium helps to regulate the flow of water in the vine. Very high potassium levels in soils can cause problems in the uptake of magnesium, and this may lead to reduced yields and poor ripening. High potassium levels in the soil can lead to high potassium levels within the grapes, having a significant effect on wine quality by causing (too) high pH. Low levels of potassium can lead to low sugar accumulation in the grapes, reduced grape yields and poor vine growth in general.

98
Q

Explain the role the following important nutrient plays in vine growth and reproduction: PHOSPHORUS.

A

Phosphorus is important for photosynthesis. Vines need only a small amount, and usually there is enough phosphorus naturally present in the soil. A deficiency in phosphorus leads to poorly developed root systems (and hence a diminished ability to take up water and nutrients), reduced vine growth and lower yields.

99
Q

Explain the role the following important nutrient plays in vine growth and reproduction: CALCIUM.

A

Calcium has an important role in the structure of plant cells and in photosynthesis. Calcium deficiency is rare, but can have a negative influence on fruit set.

100
Q

Explain the role the following important nutrient plays in vine growth and reproduction: MAGNESIUM.

A

Magnesium is found in chlorophyll and therefore has a key role in photosynthesis. Deficiency can result in reduced grape yields and poor ripening.

101
Q

What factors influence the uptake of nutrients?

A

Vine nutrients dissolve in soil water, which is then taken up by the roots of the vine. This means that the soil factors that influence water availability also impact nutrient availability.

102
Q

Explain why soil pH has a key influence on nutrient availability.

A

Different nutrients become more or less available at different pH levels. For example, iron is poorly available in soils with high pH.

103
Q

Name an example of a soil type with high pH.

A

Soils with a high proportion of calcium carbonate such as limestone.

104
Q

What is chlorosis and how is it caused?

A

Chlorosis is a condition in which leaves turn yellow and photosynthesis stops, so grape ripening and yields are negatively affected as a result. It is caused by a lack of iron (poorly available in high pH soils).

105
Q

What is mineralisation?

A

A process in which organisms that live in the soil (such as bacteria, fungi, earthworms, etc.) are feeding on the organic matter and converting it into either humus or inorganic nutrient compounds, available to the vine roots. It is therefore thought to be highly beneficial to encourage soil life and ecosystems within the vineyard.

106
Q

Can organic compounds, found in soils, taken up by vine roots directly?

A

No, organic nutrient compounds found in and added to soils (e.g. in the form of manure or compost) are not available in a form that the vine can take up and need to be converted into inorganic compounds.

107
Q

How does Humus effect nutrient availability?

A

Humus can increase the soil’s ability to hold nutrients.

108
Q

Different soil textures also have varying abilities to hold nutrients. Name both examples of soils with good and poor nutrient holding capacity.

A

Soils with a high proportion of clay are good at holding nutrients, whereas sandy soils are poor at holding nutrients.

109
Q

How does topography of the vineyard have an impact on the soils and their levels of nutrients?

A

Soils on slopes are often thinner and less fertile than those on plains or valley floors.

110
Q

Where does sediment come from?

A

Sediment comes from the weathering of bedrock (solid rock).

111
Q

What are the typical components of a soil?

A

Soil is the upper layer of the earth and is typically made up of geological sediment, organic remains in the form of humus, and the pores in between the sediment that contain water and air.

112
Q

What is the influence of soil in terms of wine style and quality?

A

The influence of soil in terms of wine style and quality is complex. Scientific backing to support any links between the chemical composition of soil or bedrock and particular aromas/flavours in a wine is lacking. However, the importance of the soil’s physical parameters on water availability and therefore vine growth and grape ripening is well recognised.

113
Q

What are the most important physical element of a soil?

A

Its texture and structure. The suitability of the soil for viticulture will depend on the texture and structure of the soil combined with how far the roots are able to penetrate.

114
Q

What is soil texture?

A

The texture of the soil describes the proportions of the mineral particles of sand, silt and clay. As well as sand, silt and/or clay, the soil may also contain a proportion of larger rock fragments, such as gravel or pebbles (larger than gravel). These larger particles improve water drainage but lower water- and nutrient-holding capacity.

115
Q

What is the effect of a high proportion of clay in a soil?

A

Soils with a high proportion of clay are said to be finely textured; clay particles are very small, and because of this have a large surface area compared to their volume, so they are very effective at holding water and nutrients. Soils that have a very high clay content are sticky and may form aggregates that are hard for vine roots to penetrate and challenging for soil cultivation. The vines’ roots may be limited to cracks or gaps between the aggregates.

116
Q

What is the effect of a high proportion of sand in a soil?

A

Sand particles are relatively large and have a small surface area compared to their volume. They therefore have limited capacity to hold water and it can drain through them easily. They are also poor at retaining nutrients. Sandy soils have a loose texture, making them workable and easy for vine roots grow through. Soils that are high in sand or larger particles such as gravels or pebbles are very loosely structured and, in fact, need some clay to help bind them together. Very sandy or stony soils have poor water and nutrient-holding capacity, but may prove suitable if the vine roots are able to grow freely and deeply, giving a large area over which the vine can obtain water.

117
Q

How does ‘silt’ compare to ‘clay’ and ‘sandy’ soils?

A

Silt has particles of intermediate size and its properties sit between that of clay and sand.

118
Q

Define ‘loam’?

A

‘Loam’ describes a soil that has moderate proportions of clay, silt and sand.

119
Q

What is soil structure?

A

The structure of the soil describes how the mineral particles in the soil form aggregates (crumbs). The size, shape and stability of these aggregates are also important for determining water drainage, root growth and workability of the soil.

120
Q

What is ‘humus’ and how does it influence soil structure?

A

Humus is organic matter in the soil that is formed by the partial decomposition of plant material by soil microbes and earthworms. It has a spongey texture, large surface area and is able to adsorb water and nutrients. It helps to bind soils together and can help soils to retain water and nutrients.

121
Q

The suitability of the soil also depends on the climate in which the vine is growing. Give an example.

A

Free draining soils can be beneficial for avoiding excess water in rainy climates (e.g. the gravelly soils in the Haut-Médoc). Excess water can displace oxygen in the soil, and oxygen is essential for the respiration of vine roots and soil organisms. Waterlogged soils can lead to reduced vine growth and eventually vine death. There are several options that the grape grower can take if the soil is not completely suitable; for example, fertilisers can be applied to soils that are very nutrient poor, irrigation can be installed if soils are too free-draining.

122
Q

How is (a region’s) climate defined?

A

A region’s climate is defined as the annual pattern of temperature, sunlight, rainfall, humidity and wind averaged out over several years (30 years in the timescale generally agreed). The climate does not change from one year to the next, although it can alter over a period of decades.

123
Q

Why does climate influence the style and quality of wine made in a specific region?

A

Temperature, sunlight and water from rainfall have a vital influence on the vine’s ability to grow and ripen grapes, and the style and quality of wines that can be made in a region. For this reason, a number of models of climate classification have been created, grouping vineyard areas into different climatic bands. These models can often help in the comparison of different global vineyard areas and the resulting wine styles that they can make successfully.

124
Q

What is meant with GDD?

A

Growing Degree Days, a model of heat summation during the growing season that was created by Amerine and Winkler (1944). It was originally intended for the vineyard regions in California.

125
Q

How is GDD being calculated for Celcius?

A

To calculate the GDD: (1) subtract 10 from the average mean temperature of a month in the growing season, (2) multiply this by the number of days in that month and (3) make the same calculation for each month in the growing season and add together the totals to get the GDD. (Any months with a negative value would not be counted.)

126
Q

Why does GDD use a 10 degree correction on the average mean temperature?

A

Below this temperature vines cannot grow

127
Q

What are the growing season months in the Northern and Southern Hemisphere?

A

April to October in the Northern Hemisphere, October to April in the Southern Hemisphere

128
Q

How many ranges does the GDD climate classification have? And define the upper and lower bands.

A

As part of the model, the GDDs are grouped in five ranges. This makes the data easier to use and communicate. The climate of a region in ‘Winkler Zone I’ (lowest GDDs) is cool, whereas a region in ‘Winkler Zone V’ (highest GDDs) is very hot.

129
Q

What is meant with HI?

A

The Huglin Index, created by Huglin (1978), widely used in Europe.

130
Q

How does the HI differ from the GDD?

A

The Huglin Index uses a similar formula to GDD, but differs in that the calculation takes into account both mean and maximum temperatures and the increased day length experienced at higher latitudes.

131
Q

What is meant with MJT?

A

The Mean temperature of the warmest month, a model created by Smart and Dry (1980).

132
Q

Explain MJT.

A

MJT uses the mean temperature of either July in the Northern Hemisphere or January in the Southern Hemisphere (J in MJT mean January/July temperature) as well as measures of continentality, humidity and hours of sunshine. Again, the temperatures have been divided into six bands to aid description and communication, ranging from cold to very hot.

133
Q

What is meant with GST?

A

Growing season temperature

134
Q

Explain GST.

A

This model uses the mean temperature of the whole growing season and, again, these temperatures are grouped into climatic bands ranging from cool to hot. It is very closely correlated to GDD and is easier to calculate.

135
Q

Although more specific climate classifications are required in viticulture, in very broad terms the majority of the world’s wine regions are categorised under three headings: maritime, Mediterranean and continental. On what climate classification model are these categories based?

A

These categories are based very loosely on part of Köppen’s climate classification (which was first created in 1900), and consider both temperature and rainfall patterns. The categories apply to wine regions in temperate zones, not vineyards located in the tropics.

136
Q

Define a maritime climate. What wine region is typical for this climate?

A

Maritime climates experience low annual differences between summer and winter temperatures. Rainfall is also relatively evenly spread throughout the year. An example of a maritime region is Bordeaux.

137
Q

Define a Mediterranean climate. What wine region is typical for this climate?

A

Mediterranean climates experience low annual differences between summer and winter temperatures. The annual rainfall tends to fall in the winter months, giving dry summers. Examples include Napa Valley and Coonawarra.

138
Q

Define a continental climate. What wine region is typical for this climate?

A

Continental climates have more extreme differences between summer and winter temperatures. They often have short summers and cold winters with temperatures rapidly changing in the spring and autumn. Examples include Burgundy and Alsace.

139
Q

What temperature categorisation does WSET use?

A

WSET uses cool, moderate, warm and hot climates temperature categorisations.

140
Q

What is the temperature range for a cool climate?

A

Cool climates are regions with an average GST of 16.5°C or below.

141
Q

What is the temperature range for a moderate climate?

A

Moderate climates are regions with an average GST of 16.5–18.5°C.

142
Q

What is the temperature range for a warm climate?

A

Warm climates are regions with an average GST of 18.5–21°C.

143
Q

What is the temperature range for a hot climate?

A

Hot climates are regions with an average GST in excess of 21°C.

144
Q

Explain some general climate effects in continental climates.

A

The extreme winters found in continental climates can lead to winter freeze, but often the rapid increase in temperature in the spring can lead to even budburst (with little chance of spring frosts). There is also a rapid drop in temperature in the autumn and therefore a shorter growing season.

145
Q

Explain some general climate effects in warmer climates versus colder climates.

A

In regions with warm summers, the risk of not accumulating sufficient sugar in the grapes is reduced. However, the grapes can have high sugar levels and low acidity levels by the time aroma compounds, colour and/or tannins have reached optimum ripeness, and this can lead to wines with high levels of alcohol and low levels of acid. In climates with cool growing seasons, the grapes may be too low in sugar and too high in acid in the coolest years.

146
Q

Explain some general climate effects in cool, cloudy, rainy climates.

A

Vines that are grown in climates that are cool, cloudy and rainy in late spring or early summer are susceptible to poor flowering and fruit set. Climates with even levels of rainfall throughout the year, such as maritime climates, are less likely to experience extreme water stress. However, too much water can cause excessive vine vigour. Rain also increases humidity, and can increase incidence of fungal disease, which can be particularly problematic near harvest time.

147
Q

Define continentality.

A

Continentality is a measure of the difference between the annual mean temperatures of the hottest and coldest months.

148
Q

Explain how the location (land inwards or near the coast) influences continentality.

A

Regions near the coast or that are nearby a large body of water have low continentality and tend to be categorised as either ‘maritime’ or ‘Mediterranean’. Large bodies of water, such as oceans, seas or large lakes, heat up and cool down more slowly than landmasses. Therefore, in winter they have a warming effect on the surrounding air and in summer they have a cooling effect. Regions that are far inland or are protected from ocean influences have high continentality and tend to be categorised as ‘continental’.

149
Q

How is (a region’s) weather defined?

A

A region’s weather is the annual variation that happens relative to the climatic average. Some regions experience greater variation in this pattern than others.

150
Q

Define vintage variation.

A

Weather can have a significant influence on the wines produced in that year and this is often termed vintage variation. The weather in a particular year can influence sugar and acid levels, and tannin and aroma/flavour ripeness. This may have a subsequent effect on how the wines are made in the winery (e.g. adjustments to the must or wine may be beneficial, greater extraction may be desirable for red wines in warmer years to balance higher alcohol levels, etc.).

151
Q

Give both an example of a winegrowing region with a large and with almost non vintage variation.

A

The amount and timing of rainfall in Bordeaux can vary quite considerably: in 2007 the region was cool, cloudy and wet during most of August, whereas in 2003 high temperatures and near drought conditions were experienced. The weather in other regions, such as Central Valley in California, is far more predictable, with hot dry weather from one growing season to the next.

152
Q

Give an example of a wine in which vintage variation is undesirable.

A

In some wine styles, vintage variation is expected and often welcomed. In others, such as non-vintage sparkling wines and many high-volume, inexpensive wines where consumers are expecting the wine to taste consistent regardless of the year, vintage variation is not desirable and winemaking choices may be made that reduce any vintage variation in the final wine.

153
Q

How can weather affect yields?

A

Rainy years can bring more fungal disease, reducing yields; spring frosts can also lead to significant reductions in yield, especially if no frost protection is available.

154
Q

Explain the supply and demand effects of high and low harvest yields.

A

Having substantially less wine to sell in a particular year can often be extremely problematic for cash flow and customer relations (wine businesses and consumers may find a replacement if a particular product is not available, and then continue to buy the replacement product in the future). Yields that are substantially larger than normal can also be problematic. The winery may not have the capacity for the increased volume of fruit, and finding routes to market/customers for all the wine (at a profit) may be difficult.

155
Q

Climate change is admitted by the overwhelming majority of the scientific community. As an industry that is highly dependent on climate, wine production is likely to be strongly affected. What are the main measurable climate effects of climate change?

A

The main measurable effect of climate change is a rise in temperatures. It also has the consequent effect of greater evapotranspiration and therefore likelihood of water stress. Other effects include changes in the geographical distribution of rainfall, greater weather variability and a greater frequency of extreme weather events.

156
Q

What are the effects of the rising temperatures on viticulture that has already started to be witnessed?

A

In warmer temperatures, the vine cycle is faster. Budburst occurs earlier in the spring and each stage of the vine cycle becomes quicker. The increased temperatures speed up the rate of sugar accumulation and reduction of acidity, but do not quicken the ripening of most aroma and tannin compounds. In order not to compromise the ripeness of aromas and tannins, and the accumulation of colour, grapes may be picked with higher levels of sugar, causing higher alcohol levels in wines and lower levels of acidity. The more rapid fall in acidity can give wines with higher pH levels, and this could be problematic in winemaking.

157
Q

What is the effect of climate change on aroma profiles of wines?

A

The effects on aroma compounds is complex, but it is likely that, as temperatures continue to rise, the grapes from certain vineyard regions may no longer exhibit the same aroma profiles as they do now. For example, black pepper is often a characteristic of Syrah grown in moderate climates, such as the Northern Rhone. With increasing temperatures in this region, it is likely that this hallmark aroma may no longer develop.

158
Q

What are the effects of drier conditions on viticulture?

A

Drier conditions resulting from greater evapotranspiration and altered rainfall patterns may benefit some regions that currently experience plentiful rainfall in the growing season. Here, a drier environment may reduce the likelihood of fungal disease and promote the conditions of mild water stress that is thought to be positive for grape ripening. However, in regions that already experience dry growing seasons, the vines may be regularly subjected to extreme water stress, causing photosynthesis to stop and the vines’ leaves to fall off.

159
Q

Name regions that already experience excessive temperatures and/or drought.

A

A number of wine regions are starting to experience very significant problems with excessive temperatures and/or drought (e.g. parts of California and South Africa), and it is thought that at least some vineyard sites in many of these regions will be abandoned in the next 50–100 years.

160
Q

How can winegrowers prepare for the effects of climate change?

A

Many grape growers and wine businesses have already started to act, both to mitigate climate change and to better adapt to the effects of climate change. Many wine businesses now practise sustainable techniques such as using renewable energy resources and protecting natural ecosystems. To better prepare for the effects of climate change, site selection, choice of planting material and/or efficacy of different vineyard management techniques are being reviewed by forward-thinking companies.