Chapters 4-6

Question 1

What is the name of the main Eurasian vine species for winemaking?

Answer 1

Vitis vinifera.

Question 2

Why are American vines used?

Answer 2

American vines are widely used for their rootstocks rather
than producing grapes for winemaking.

Question 3

What are some of the factors a grape grower will consider when trying to decide which grape variety to select?

Answer 3

Budding and ripening times, resistance to disease.

Question 4

Why are vines grown from cuttings?

Answer 4

To grow a new vine that is the same variety. If seeds are
used they would grow into a different variety.

Question 5

What is a clone?

Answer 5

A mutation of a grape variety that has a small difference
to the original and is still genetically identical.

Question 6

Why might a new grape variety be created?

Answer 6

To thrive in certain climates and soil conditions, or have
improved disease resistance, or be able to deliver higher
quality or quantity of grapes.

Question 7

How are new grape varieties created?

Answer 7

Cross fertilisation of flowers from different vines.

Question 8

What is a crossing? Give an example of a crossing.

Answer 8

A new variety produced from vitis vinifera vines. An example
is Pinotage (Pinot Noir x Cinsault).

Question 9

What is a hybrid? Give an example of a hybrid.

Answer 9

A variety whose parents come from two different vine species. Typically at least one parent is an American vine. They are often used for rootstocks. An example used for winemaking is Vidal.

Question 10

What is phylloxera? What does it to vineyards and how is it prevented?

Answer 10

Phylloxera is an insect. It feeds on the roots of vines where
infections can enter which kills the vine. It is prevented by
grafting American rootstocks to vines.

Question 11

What are some of the reasons to use rootstocks?

Answer 11

Because they can provide resistance to Phylloxera, protection
against nematodes, resistance to drought conditions.

Question 12

What is bench grafting?

Answer 12

An automated process where short sections of vinifera
cane are joined to rootstocks by a machine and then
stored until they fuse together.

Question 13

What is head grafting?

Answer 13

In an established vineyard the vine can be cut back and
the shoot of a different variety attached to the trunk. This
is done in the vineyard and changes the grape variety of
the vine.

Question 14

What is the function of buds on a shoot?

Answer 14

Buds contain the embryonic shoots for the following year.

Question 15

What is the function of tendrils on a shoot?

Answer 15

Tendrils grip the nearby supporting structure to help the
vine stay upright.

Question 16

What is the function
of leaves on
a vine?

Answer 16

Leaves are responsible for photosynthesis. This is the
process where sunlight converts water and carbon dioxide
into glucose and oxygen.

Question 17

What are the
name of the
bunches of flowers
formed on
vines?

Answer 17

Inflorescences.

Question 18

What is
important about
managing the
one-year-old
wood on the
vine?

Answer 18

Pruning it into a cane or spur after winter to determine the
number of buds for the next years growth.

Question 19

What is the function
of the roots
of the vine?

Answer 19

Absorb water and nutrients from the soil, anchor the vine
and store carbohydrates.

Question 20

Why is heat
important for
vines?

Answer 20

Vines need heat to function. If it is too cold the vine will not
grow or will struggle to survive. Vines need at least 10°C
to grow. The amount of heat will determine which grape
variety will grow in a region.

Question 21

How does latitude
affect the
heat of a region?

Answer 21

The closer to the equator a region is the warmer it is. The
further away a region is from the equator the cooler it is.
Most vineyards are between the latitudes 30° and 50°.

Question 22

How does altitude
affect the
heat of a region?

Answer 22

Temperature decreases as altitude increases.

Question 23

How do ocean
currents affect
the temperature
of a region?

Answer 23

Warm or cold currents transport large volumes of water
across the surface of the ocean leading to localised warming
or cooling.

Question 24

How does fog affect
the temperature
of a region?

Answer 24

Fog can help cool an area of a warm climate region that
may otherwise struggle to produce high quality grapes.

Question 25

How does soil affect the temperature of a region?

Answer 25

Soils that are dark in colour or stony can absorb and reradiate heat, which can aid ripening. Soils that have a high water content conduct heat away from the vine more quickly, which can delay budburst.

Question 26

How does aspect affect the temperature of a vineyard?

Answer 26

Vineyards facing toward the equator will receive more heat. This can aid ripening in cool climates. Steeper slopes will benefit even more from this effect.

Question 27

What is continentality?

Answer 27

The temperature difference between the coldest and hottest months. Regions with high continentality will have a greater difference in seasonal temperatures. Large bodies of water will reduce continentality. Continentality will determine the length of the growing season and the total amount of heat available to the vine.

Question 28

What is the diurnal range?

Answer 28

The difference between day and night temperature. Cool nights help slow the loss of aromas and acidity in the grapes during ripening. Regions that are next to a body of water or are cloudy will have less diurnal range.

Question 29

What is winter freeze?

Answer 29

When the temperature falls below -20°C. This can damage or kill vines.

Question 30

What happens if winters are too mild?

Answer 30

The vine will not have a dormant period and may produce more than one crop per year. More insect pests may survive to attack the vine.

Question 31

What are spring frosts?

Answer 31

When cold air below 0°C collects at ground level freezing any water vapour on the vine. In spring time it can kill newly burst buds or young shoots.

Question 32

What can be used to protect against spring frost?

Answer 32

Heaters, wind machines, sprinklers, thoughtful vineyard design.

Question 33

How does sunlight affect vines?

Answer 33

Sunlight is needed for photosynthesis. The more light there is the more the vine will photosynthesise and produce glucose for growth and ripening grapes. Flowering and fruit set also benefit from sunlight.

Question 34

How does latitude affect sunlight?

Answer 34

Day length during the summer growing season is longer in vineyards that are further away from the equator. This can help grapes ripen.

Question 35

How do seas and lakes affect sunlight?

Answer 35

Vineyards near to large bodies of water experience more cloud cover. Vineyards above rivers or lake can benefit from sunlight reflected from the surface of the water.

Question 36

How does aspect affect sunlight?

Answer 36

Aspect affects the amount of sunlight a vineyard receives. Steeper slopes have a greater affect. Vineyards that face the Equator will receive more sunlight, this can be especially important in vineyards further away from the Equator.

Question 37

What are the hazards relating to sunlight?

Answer 37

Low levels of light can be a problem during flowering and fruit set where it can result in a smaller crop of grapes. If it is too sunny grapes can suffer from sunburn leading to bitter flavours.

Question 38

How does water affect vines?

Answer 38

The vine needs water for photosynthesis, and to swell its grapes during ripening. The vine accesses water through its roots. The amount of water needed will be determined by the temperature, vines need more water in warmer temperatures. Once enough leaves have grown limiting the supply of water can be beneficial for ripening.

Question 39

What are the different types of irrigation?

Answer 39

Drip - the most advanced and expensive. Computer controlled so each vines gets only as much water as it needs. Sprinklers - Cheaper than drip irrigation but waste water and can create damp conditions in the vineyard that can increase the risk of disease. Can also be used for frost protection. Flood irrigation - Very cheap but only possible in vineyards that are gently sloping and where there is access to large quantities of water.

Question 40

What are hazards relating to water?

Answer 40

Drought - vines can stop transpiration to preserve resources. If prolonged vines may suffer from water stress or stop photosynthesising. Grapes will fail to ripen and it may kill the vine. Too much water - the vine will continue to grow shoots and leaves leaving less sugar for ripening grapes and increasing shading. Waterlogged soil can cause roots to become saturated and the vine dies. Flowering and fruit set can be disrupted by heavy rainfall. Damp conditions can encourage fungal disease. Heavy rain before harvest can cause berries to swell and this will dilute flavours. Hail - Can damage grapes and vines and even destroy an entire crop. Netting can be used to protect vines.

Question 41

What are the 4 different temperature classifications for wine regions?

Answer 41

Cool - average growing season temperature of 16.5°C or below. Moderate - average growing season temperature of 16.5°C to 18.5°C. Warm - average growing season temperature of 18.5°C to 21°C. Hot - average growing season temperature over 21°C.

Question 42

What are the 3 different continentality classifications?

Answer 42

Continental - greatest temperature difference between hottest and coolest months. Short summers with rapid temperature drop in autumn. Summer can be hot and dry. Maritime - Cool to moderate temperature with low annual difference between hottest and coolest months. Rainfall spread evenly throughout the year. Mediterranean - Low temperature difference between coldest and hottest months, summers are warm and dry.

Question 43

How does the size of soil particles affect the vine?

Answer 43

Stones are large particles that can help heat a vineyard. Sand and clay soils have much smaller particles. Clay soils store more water. Many soils are made up of a mixture of sand and clay soils known as loam.

Question 44

What is humus?

Answer 44

Decomposing plant and animal materials that are rich in plant nutrients and have excellent water retaining properties.

Question 45

What nutrients does a vine need?

Answer 45

Nitrogen, phosphorus and potassium. These are naturally occurring in the soil and are taken up by the roots. Vines do not need high levels of nutrients. If nutrients are too high vines produces dense leafy canopies. If nutrients are too low vines can develop problems such as chlorosis.

Question 46

What are some of the considerations behind selecting a site to be used for a vineyard?

Answer 46

Environmental conditions - average temperature, rainfall, sunlight hours, soil fertility. Business considerations - the proximity to infrastructure, availability of workforce, accessibility for machinery, cost of land. Grape variety - Must be suited to the climatic conditions of the site, there must be demand for grapes. In the EU there may be legal restrictions on grapes used.

Question 47

Why are 'old vines' used?

Answer 47

Old vines produce fruit of exceptional quality often with greater concentration of flavours. However, the yield decreases with age and vines can become susceptible to disease.

Question 48

Why are vines managed?

Answer 48

To maximise the production of fruit at the desired quality level as economically as possible.

Question 49

What is head training?

Answer 49

Vines have relatively little permanent wood. This can mean only a trunk or a few short arms around the top of the trunk.

Question 50

What is cordon training?

Answer 50

Vines have a trunk with one or more permanent horizontal arms, usually spur pruned. This takes longer to establish because it requires a greater amount of permanent wood. However it can make mechanisation easier.

Question 51

What is pruning?

Answer 51

The removal of unwanted leaves, canes or permanent wood. It shapes the vines and limits its size. Winter pruning determines the number and location of buds that will form shoots in the coming year. Summer pruning involves trimming the canopy and leaf removal.

Question 52

What are the two types of winter pruning?

Answer 52

Spur pruning - spurs are short sections of one year old wood that have two to three buds. These will be distributed along a cordon or around the head of the vine. Replacement cane pruning - Canes are longer sections of one year old wood with eight to twenty buds. These are often tied to a trellis.

Question 53

Why would a grape grower choose not to use a trellis system?

Answer 53

Untrellised vines (bush vines) are better suited to warm or hot, dry and sunny regions where the extra shade can help protect the grapes. In cool or wet regions the shade can impede ripening and lack of airflow can promote disease.

Question 54

Why would a grape grower choose to use a trellis?

Answer 54

The arrangement of shoots can help control how much sunlight reaches the grapes. An open canopy will have better air circulation. Trellising will aid mechanisation.

Question 55

What is VSP?

Answer 55

Vertical shoot positioning. The shoots are trained vertically and tied into place on the trellis.

Question 56

What is planting density?

Answer 56

The number of vines planted in a given area

Question 57

What are the factors that affect planting density?

Answer 57

Availability of water and nutrients. If very limited water availability - low planting density will allow each vine access to water. If low nutrients and sufficient rainfall - vines will grow lots of vegetation where there is enough water. Planting at high density will encourage competition and therefore promote better quality fruit development. If high levels of nutrients and sufficient rainfall - very fertile soils are not suitable for viticulture. High density planting is not enough to limit growth, so vines are planted at low density with multiple cordons or canes. This can produce high quality fruit at high yields.

Question 58

What is the yield?

Answer 58

A measure of the amount of grapes produced. Some regions in the EU have legal restrictions on yields. An estimate of yield can be made by the number of buds left on the vine after pruning but it can be affected by frost, pests, disease. Green harvesting can reduce yields by removing grapes after véraison.

Question 59

How does yield affect quality?

Answer 59

It is hard to make any solid link between yield and quality. Traditionally the view was that high quality fruit can only be achieved by low yields but actually there are a number of factors involved.

Question 60

What are the pests that can affect vineyards?

Answer 60

Phylloxera - an insect that feeds on the roots of vines where infections can enter which kills the vine. It is prevented by grafting American rootstocks to vines. Nematodes - microscopic worms that attack the roots of the vine and can transmit viruses. Sanitising the soil and planting on resistant rootstocks can help to prevent them. Birds and mammals - a number of animals like to feed on grapes. Half eaten or crushed grapes will lead to an increased risk of fungal disease. Netting or protective fencing can be used as a deterrent. Insects - can feed on grapes and leaves. Can be treated with insecticides or integrated pest management.

Question 61

What are other diseases that can affect vines?

Answer 61

Viruses - these limit the vine's ability to function and can reduce yields and quality. They are contagious and persistent, spread by cuttings or nematodes, and there is no cure. Bacterial diseases - these can reduce grape quality or kill vines. They are typically spread by insects called sharpshooters. There are no treatments.

Question 62

What are the viticultural practices available to grape growers wishing to reduce their chemical use?

Answer 62

Sustainable agriculture - restricted use of man-made chemicals, prevent pests using natural methods, only spray when needed. Integrated pest management means encouraging predators of pests in the vineyard to control populations naturally. Organic agriculture - a limited number of traditional treatments are permitted in small quantities. Accreditation is required to use the term 'organic' on the label. The vineyard must undergo a period of conversion before it can be certified. Biodynamic agriculture - adopts organic principles but also incorporates philosophy and cosmology. The vineyard soil is seen as part of connected system with the planet. There are also certifications for this.

Question 63

How does a grape grower know when the grapes are ripe?

Answer 63

When they have the ideal balance between sugar, acid, flavour and tannin.

Question 64

When does harvest start?

Answer 64

Ideally when the grapes are at the optimum level of ripeness. This can be affected by poor weather.

Question 65

What are the advantages and disadvantages of machine harvesting?

Answer 65

Disadvantages - they are not selective, can include MOG, can only be used on flat land, cannot pick whole bunches. Advantages - they are quick, can work through the night.

Question 66

What are the advantages and disadvantages of hand harvesting?

Answer 66

Disadvantages - It is slow, more labour intensive, more expensive. Advantages - greater selection, less damage occurs, can pick whole bunches, can work on steep slopes.

Question 67

What happens during early shoot and leaf growth?

Answer 67

Shoots grow until the vine flowers. Initially this is fuelled by the vine's carbohydrates reserves, but then continues via photosynthesis. The vine needs good water supply and sufficient nutrients. Shoots are tied to a trellis if necessary. Spraying can occur

Question 68

What happens during flowering and fruit set?

Answer 68

When the inflorescences start to flower the vine needs warm temperatures and little or no rainfall. Fruit set occurs when the flowers develop into grapes. If more flowers than normal fail to fertilise the condition is known as coulure. Grapes can form without seeds that remain small, this is known is millerandage. Both of these conditions reduce yields and stem from cold, cloudy or rainy weather. Spraying can continue.

Question 69

What happens during véraison and berry ripening?

Answer 69

After fruit set the grapes grow over six to eight weeks. Véraison signals the point at which the grapes begin to ripen, grape skins change colour, grapes will swell with water, sugar levels rise and acid levels drop, colour pigments and flavour compounds are formed, tannins develop. Warm and sunny conditions with mild water stress are ideal. Summer pruning can occur. Spraying can continue.

Question 70

What happens during harvest?

Answer 70

Ideally the weather at harvest is dry. Spraying must have finished early enough to ensure there are no residues in the wine. Grapes are picked.

Question 71

What happens during winter dormancy?

Answer 71

As the weather becomes colder, the growing season ends, shoots become woody and are known as canes, the leaves fall off. Winter pruning takes place.

Question 72

What happens during budburst?

Answer 72

Buds swell and burst growing into new shoots. This generally starts when the temperature reaches above 10°C, but is different for different varieties. New shoots can be killed by spring frosts. Spraying, if practised, begins at this time.