L3 - The Vine Chapters 4 & 5

Question 1

How does a grape variety grow/propagate?

Answer 1

Grape varieties cannot be grown with grape seeds. Planting seeds will create an entirely new varietal.

Instead 1 of 2 methods is used:

Cutting - a cutting is a section of a vine shoot that is planted to grow as a new plant. Usually comes from a commercial nursery & sold to growers

Layering- a cane of a plant is bent down & buried in the ground. The buried section takes root, once roots are established, the cane linking the new growth to the original plant is cut. (This method is used less often due to phylloxera risks)

Question 2

What are the two most important vine species?

Answer 2

1) vitis vinifera- eurasian species which produces nearly all grapes in winemaking for several 1000 years

2) American vines- not used for wines bc the yield is considered poor BUT used for grafting rootstocks to combat phylloxera

Question 3

What are clones?

Answer 3

Individual vines which are genetically identical to the same grape variety but which may demonstrate significant variations or mutations.

Question 4

What do grape growers usually do with positive mutations/clones?

What are some of the possible benefits?

Answer 4

Vines with positive mutations are often selected for further propagation either through cutting or layering.

Benefits may include better quality fruit or disease resistance.

When grape growers order new plants from a nursery they often specify not only grape variety but also the clone.

Question 5

What is an example of a mutation of the same variety with significant variation in clones?

Answer 5

The Pinot grape variety has several notable clones:

Pinot Blanc
Pinot Gris
Pinot noir
Meunièr (used champagne)

All are technically / genetically the same grape varietal of Pinot but significantly different when used in winemaking

Question 6

How are new vine varieties created?

Answer 6

Through cross-fertilization (pollen from male part of one vine is transferred to female part of another vine- pollinated flower develops a grape with seeds)

Question 7

What are 3 ways to create new varietals?

Answer 7

1) planting a seed - wait 2/3 years to see grape characteristics

2) crossings - new variety from 2 parents of the same species (most common with vitis vinifera). Ex: cab sauv is cab franc w/ sauv blanc.

3) hybrids - new varietal from 2 different species (ie. American with vitis vinifera for grafting)

Question 8

What does phylloxera do?

Answer 8

Killed many European vineyards in 1900s.

During 1st phase of life phylloxera feeds on wounds on the roots of vines. Kills and weakens vines over a few years.

American vines are resistant bc they evolved with phylloxera with a sticky sap which clogs the parasite’s mouth. Also the vines form protective layers behind the feeding wound preventing secondary infections

Question 9

What else can grafting rootstocks be used for besides guarding against phylloxera?

Answer 9

• can protect against nematodes
  -provide better resistance to drought conditions

Question 10

What is the most popular technique of grafting?

Answer 10

Bench grafting

An automated process where the v. Vinifera and rootstock are joined together by a machine and stored in a warm environment to encourage the 2 parts to fuse together. Once that happens vines can be planted

Question 11

What is head grafting used for?

Answer 11

Head grafting - technique where an existing vine is cut back to its trunk and a bud or cutting of the new variety is is grafted onto the trunk.

Why is this done?

If graft is successful it will yield the fruit of the new variety at the next vintage. So this saves a lot of time bc typically it takes a newly planted vine a minimum of 3 years to produce a commercial crop. This technique allows for quicker adjustments based on market demand. Cheaper than replanting an entire vineyard and uses an Established root system

Question 12

What are the 5 things a vine needs?

Answer 12

1) heat
(if not enough heat the vine will struggle to survive. Below 50F or 10C a vine will not grow)

2) sunlight
3) water
4) carbon dioxide

(sunlight combines CO2 and H2O to spur photosynthesis -glucose and oxygen)

5) nutrients

(the vine uses glucose to extract nutrients from soil to grow & ripen grapes)

Question 13

What is the annual growth cycle of a vine?

Answer 13

Winter - vines are dormant & no green parts on plant

Budburst- start of growing season when new shoots start to grow

Fruit set- Late spring/early summer- vine flowers & small grapes form known as fruit set

Mid summer- grapes grow but are hard in texture & green in color w/ high acidity & low sugar

Veraison-Late summer/early autumn- grapes swell w/ water, sugar levels rise, acid levels drop, flavors develop- color change from green to blue/black, pink or golden depending on variety.

Harvest- grapes harvested in late autumn. Growing season comes to an end

Question 14

At what temp is a vine unable to grow?

How does temperature impact varietal selection?

Answer 14

Vines cannot grow below 50 F (or 10 C). As a result vines go dormant and don’t bud until spring.

The amount of heat in a region defines which varietals can be grown. Riesling is able to ripen in cooler climates. In contrast grapes like Grenache must have a warm climate to ripen.

Question 15

What factors affect heat?

Answer 15

1) LATITUDE - btwn 30 & 50 (North/South)

2) ALTITUDE- higher alt, lower temp (ex. Cafayate, Argentina is close to the equator than most vineyards, but higher altitude makes it cooler)

3) OCEAN CURRENTS- cooling/warming air
Humboldt/Chile &Benguela/South Africa = cools
Gulf Stream/Europe = warms

4) FOG -cooling effects to warmer regions

5) SOIL
dark soil/soil with high stone/rock content- reradiates heat, important for cool climates

6) ASPECT -direction of slope, most heat facing equator

7) CONTINENTALITY -difference btwn hottest/coldest months. closeness to large bodies of water creates less continentality (longer growing season)

8) DIURNAL RANGE

Question 16

At what temperature do vines freeze and die? How is the risk mitigated?

Answer 16

Vines freeze and can die if temps fall below -20C (4F). The graft is the part of the vine most at risk, so earth can be used to cover up and protect it (called earthing up)

Without winter vines may produce more than one crop, however, this will shorten the life of the vine and lower the quality of the grapes

Question 17

At what temperature does spring frost occur? What is the impact on buds and shoots? How is it mitigated?

Answer 17

Spring frost (which occurs when cold air below 0C/32F collects at ground level, freezing any water vapor either on the ground or vine). If this happens during spring, it can kill newly burst buds or shoots.

To prevent it growers may use 4 methods:

1) Heaters - creates movement in air to prevent cold air from settling
2) wind machines - draws warm air from above to keep temp at ground level
3) sprinklers- spray vines & release heat into plant tissue as water freezes
4) thoughtful vineyard design -planting vineyards on slopes & training vines high

Question 18

What are risks associated with summer?

Answer 18

Prolonged and extreme heat in the summer will slow and stop growth of vines even if there is sufficient water. Also risk of wild fires.

Question 19

What is continentality?

Answer 19

The variation of temperature between seasons (hot and cold months).

Large bodies of water heat & cool down slowly, thus reducing continentality. Inland regions not near water have high variation = high continentality

Question 20

What is diurnal range?

Answer 20

The variation of temperature during the day (difference between day time and night time temps)

cool nights slow the loss of aromas and acidity during ripening

warm days accelerate ripening

As a result, large diurnal range can produce fresher and more aromatic wines

Proximity to water reduces the diurnal range as water can hold enough warmth to keep a vineyard warm overnight

Cloud cover can also impact diurnal range bc temperature drops more quickly on clear nights where there is no insulating blanket of cloud

Question 21

Why does a vine need sunlight?

Answer 21

The more light the more a vine will be able to photosynthesize, which leads to greater glucose produced for growth and ripening of grapes.

Question 22

What factors affect sunlight?

How do they affect sunlight?

Answer 22

LATITUDE- day length is longer the further a vineyard is from the Equator. Extra sunlight from longer days is important in cooler wine growing regions.

ASPECT - Slopes can increase a vineyard’s access to sunlight. Steeper slopes that face the Equator will benefit the most from this effect. The greater the distance from the Equator the weaker the sun’s energy

SEAS AND LAKES- Vineyards near large bodies of water experience more cloud cover, whereas those that are more inland tend to be sunnier. However, vineyards situated above rivers or lakes can benefit from sunlight reflected from the water’s surface.

Question 23

What are some hazards that can effect sunlight?

Answer 23

• Cloudy conditions (can result in smaller crops, slow down photosynthesis, & stop grapes from ripening fully)

-Intensely sunny conditions- can cause sunburn to grapes, leading to bitter flavors in the skins.

Both can be managed w/ vine canopies to arrange leaves so that they either maximize sunlight in cloudy areas, or provide enough shade in extremely sunny regions.

Question 24

Why does a vine need water?

Why do vines need more water in warmer climates?

When can you slow down receipt of water to a vine?

Answer 24

For photosynthesis.

Vines need more water in warmer temperatures, because the higher the temp the faster water will evaporate from the vine’s leaves. This slows down photosynthesis which blocks shoot growth.

However, once a vine has a sufficient amount of leaves, however, limiting water is beneficial so that the vine will focus on grape ripening rather than further shoot growth.

Question 25

Aside rainfall, which is the most important water source for vines, what are the 3 methods of irrigation?

Answer 25

1) Drip irrigation

The most common technique where each vine has their own dripper which is controlled by computer to ensure the optimum amount of water.

2) Sprinklers

Water is pumped and showered over vines. Less optimal, wastes water, can increase damp conditions & therefore disease

3) Flood irrigation

A very cheap method, that is only possible in vineyards that are flat or gently sloping, & close to large quantities of water

Question 26

What are 3 potential water hazards?

Answer 26

1) Drought

photosynthesis stops, leaves wilt, grapes fail to ripen

2) too much water

vines will overgrow shoots during ripening season, leaving less sugar for ripening grapes.

Also can lead to waterlogged soil which causes the roots to die due to lack of O2

heavy rain -disrupts flowering & fruit set, before harvest can cause berries to swell diluting flavors or causing them to split attracting fungus

3) hail

damages grapes and vines. Netting can be installed to prevent

Question 27

What defines a region’s climate?

How is it different from weather?

Answer 27

Climate- The annual pattern of temperature, sunlight & rainfall averaged out over several years.

Typically does not change, however, climate change has led to growers taking action to adapt and mitigate effects.

Weather- annual variation that happens relative to the climatic average.

Some regions (ie. Bourdeaux) experience more variation than others. (ie. 2013 was cool/wet vintage & 2015 was warm & dry)

Question 28

What are the temperature ranges for cool, moderate, warm & hot climates typically during the growing season?

Northern Hemisphere -April to Oct

Southern Hemisphere- Oct to April

Answer 28

1) Cool climates - defined as average growing season of 62 F (16.5 C) or less

2) Moderate climates - defined as average growing season of 62 F to 65 F (16.5 C to 18.5 C)

3) Warm climates - defined as average growing season of 65 F to 70 F (18.5 C to 21 C)

4) Hot climates - defined as average growing season of 70 F (21 C) or above

Question 29

What are the 3 main climatic classifications which take into account temperature as well as the region’s continentality, sunlight and rainfall?

Answer 29

1) Continental Climate

2) Maritime Climate

3) Mediterranean Climate

Question 30

Describe a Continental Climate.

Answer 30

-Have the greatest difference in temperature between hottest and coldest months (high continentality)

-Characterized by short summers with a rapid, large temp drop in autumn

-Cool continental climates (ie. Chablis/Champagne) are at risk from spring frost

-Climate is best suited to varieties that bud late and ripen early

Question 31

Describe a Maritime Climate.

Answer 31

• Cool to moderate temps

-Low annual difference between hottest & coldest months (low continentality)

-Rainfall easily spread throughout the year -helps moderate temp. Means warm enough for grapes to continue to ripen into autumn.

-Rainfall - tends to be evenly spread - moderates temperatures - temps are warm enough for grapes to continue ripening far into the autumn.

Question 32

Describe a Mediterranean Climate.

Answer 32

• Characterized by low temperature difference between hottest & coldest months

-Summers tend to be warm and dry

-Extra warmth & sunlight leads to wines that are fuller bodied, riper tannins, higher alcohol, lower levels of acidity

Question 33

What is the role of soil to the vine?

Answer 33

Supplies water and nutrients.

Composition is made of tiny particles of different sizes as well as stones or rocks, and humus (organic matter such as decomposing leaves)

Question 34

Describe the different types of soil particles.

Answer 34

-Stones/rocks - the largest soil particles. Not always present in vineyards.

Stones can help with drainage and heating up vineyards

-Sand - larger than clay. does not hold water well, but like stones better for drainage

-Clay -smallest. Water binds to clay -good for retaining. but too much rain with clay soil can lead to waterlogging

-Hummus- decomposing plant & animal materials

Question 35

What is the best type of soil generally?

Answer 35

Loam - a mixture of sand and clay particles .

Have good drainage but also retain enough water for vine growth

Question 36

What are the most important nutrients for a vine?

Answer 36

Nitrogen, phosphorous and potassium.

Vine levels do no need high levels of these nutrients to thrive.

Too much can lead to leaf overgrowth which shades the fruit too much

Lack of nutrients slows or stops photosynthesis, this fertilizer must be used at times to restore them.

Question 37

What happens when there are cold temperatures in the spring?

Answer 37

In addition to spring frosts which can kill buds and shoots, cold temperatures can also delay bud burst which shortens the growing season.

This in turn can make it harder for grapes to fully ripen.

Flowering and fruit set can also be disrupting resulting in smaller yields of grapes.