What is the optimal latitude for growing vines around the world?
Between the 30th and 50th latitudes north and south of the Equator.
Why isn't it possible to cultivate grape vines close to the Equator?
Because areas close to the Equator have annual average temperatures that are far too high which do not allow the vine to go dormant. And if a vine is unable to go dormant, it'll produce less-than-optimal fruit and tire out in only 15-20 years.
There is one place in Northern Brazil, Vale de São Francisco, that is capable of two harvests per year.
What are the 2 main species of vine?
1. Vitis vinifera
2. North American Vines (3 chief species):
- Vitis labrusca
- Vitis riparia
- Vitis rupestris
What is phylloxera?
- A fungal disease
- A viral disease
- A North American root louse
A North American root louse.
Of the two main vine species, which one is more resistant to phylloxera?
How does it protect itself?
North American vine species are more resistant to phylloxera. It is for this reason American rootstocks are widely used across the world.
The North American vine protects itself from phylloxera by seeping a sticky sap that inhibits the louse from eating, and the vine generates a defensive layer behind a wound which prevents the louse from damaging the plant material further.
Are there any places in the world today that remain free of phylloxera?
Yes, the major ones are:
- Canary Islands
- Some areas in South Australia and Argentina
Of the two main vine species, which is the most widely used around the world for quality wine production?
Vitis vinifera is most used for fine wine grape growing in the world.
The grape varieties we all know by name are from the Vitis vinifera family, such as Sauvignon Blanc, Chardonnay, Pinot Noir, Zinfandel, Syrah, and Cabernet Sauvignon.
Where can Vitis vinifera trace its origin to?
How long ago did it first appear?
Vitis vinifera is a Eurasian grape that can trace its roots back 6000-8000 years to the Caucasus region (modern day countries of Georgia, Armenia, Azerbaïdjan, and a few others).
What are some primary differences between Vitis vinifera and North American vines in terms of winemaking?
- known to have more desirable aromas for wine
- considered to produce higher-quality grapes for the production of fine wine
North American vines:
- more resistant to pests and diseases than vinifera
- generally better suited to extreme climates than vinifera
What are 3 different ways a vine can be propagated?
1. Clonal selection: when beneficial mutations occur in a vine and a nursery or viticulturist isolates and propogates the new, positive characteristics;
2. Cutting - (aka Massale Selection) when a section of a shoot is cut off from an existing vine and planted in order to grow a brand new plant. Viticulturists do this to safeguard and perpetuate the positive characteristics of the original plant;
3. Layering: A vine's 1 year-old cane is bent into the ground and partially buried with the tip of the cane poking out above ground; the buried part grows roots and establishes itself as a new plant.
Explain grafting and its benefits.
Grafting is a procedure used to fuse budwood of a desired variety (usually V. vinifera) onto another rootstock (usually a North American vine).
This technique was discovered to be both useful and necessary after phylloxera decimated European vineyards in the mid-to-late 1800s. The idea is to have a phylloxera-resistant vine that produces V. vinifera.
An added benefit is that North American rootstocks are found to be resistant to nematodes, drought, and alkaline soils, unlike V. vinifera.
What is head grafting and why is it used?
Head grafting is when a vine's top, or head, is cut off its trunk and the cutting of a new variety is grafted on to where the old head was.
The purpose of head grafting is to switch out grape varieties instead of uprooting and replanting an entire vineyard. Head grafting is a lot less expensive than replanting an entire vineyard with the added bonus of keeping the established trunk and roots.
Name 3 different ways to create new grape varieties.
What is cross-fertilization?
Name a few reasons why a viticulturist might want to cross-fertilize.
Cross-fertilization is when a viticulturist takes the pollen from the male part of one vine's flowers and fertilizes the female parts of a different vine's flowers to create a new grape variety.
The cross-fertilized flowers will grow into grapes, which will have seeds. Those seeds are collected, later planted, and if those seeds grow into a viable plant, a new grape variety is born.
Reasons to cross-fertilize:
- To create a disease resistant variety;
- To adapt the new grape to climate extremes or drought;
- To increase quality or yields.
What is the difference between crossings and hybrids?
Crossings: when a new grape variety is created by crossing parents of the same vine species, e.g. Cabernet Sauvignon (Sauvignon Blanc x Cabernet Franc - both V. vinifera).
Hybrids: when at least two different vine species, usually a North American vine and a vinifera vine, are crossed to create a brand new vine species, e.g. Concord and Vidal Blanc (only 1 parent is V. vinifera).
What is the crossing of Cabernet Sauvignon?
Cabernet Franc x Sauvignon Blanc
What is the crossing of Müller-Thurgau?
Riesling x Madeleine Royale
What is the crossing of Pinotage?
Cinsault x Pinot Noir
What are the 4 main parts of a vine?
- Permanent wood
- 1 year-old wood
- Green parts (also known as the canopy: leaves, grapes, tendrils, etc.)
Explain the importance of a vine's leaves.
Leaves are what drive the plant's growth.
Via photosynthesis, leaves use sunshine to convert water and CO2 into the things it needs to grow: glucose and oxygen.
What is transpiration?
Transpiration is how a vine takes water up through its roots and disperses it to its leaves.
What are the buds on a vine?
Buds are primordial shoots found between a shoot and a leaf. Buds will initiate next year's growth as a shoot.
What is the difference between a cane and spur?
They're both 1 year-old wood from the previous year's growth. However, the main difference between them is how may buds each has.
Cane: a long woody branch with 8 to 20 buds
Spur: a short woody branch with only 2 to 4 buds
What are some important factors to consider when deciding where to establish a new vineyard?
1. Environmental and climate considerations
- location and aspect of proposed vineyard
- soil type/fertility, drainage, average sunlight/rain
2. Trade and commerce considerations
- how remote is the vineyard?
- how easy will it be to find employees or help at harvest?
3. What grapes will do well here?
- which varieties suit the climate?
What are the 2 main types of vine training?
1. Head trained
- usually just a trunk with a couple of spurs or replacement canes, no permanent "arms";
2. Cordon trained
- a trunk with one or two permanent arms, or "cordons", that look like a bent extension of the trunk.
Give 2 examples of head-trained vines.
Bush vines tend to produce a lush canopy, so they perform best in hot regions such as Jérèz or Southern Rhône where the grapes need the extra shade.
Bush vines are generally head-trained and spur-pruned (meaning, 2-4 buds on each 1 year-old growth).
On what training system are you most likely to see replacement-cane pruning?
On head-trained vines.
If a head-trained vine has 1 cane, it's called Single Guyot.
If a head-trained vine has 2 canes, it's called Double Guyot (photo is of Double Guyot).
Describe Vertical Shoot Positioning (VSP).
Where is VSP commonly seen?
VSP is commonly seen in cool climates.
VSP is a cordon-trained vine whose shoots are positioned in an upward direction attached to the wires that connect posts within a row in a vineyard.
Attaching the canopy to wires allows air circulation and the grapes to be exposed to direct sunlight.
What are high-trained and low-trained vines?
High-trained vines are vines that are trained high off the ground to avoid frost and humidity.
Low-trained vines are vines that are trained closer to the ground so the grapes can benefit from radiating heat coming off the ground.
What are the 5 most important things a vine needs to survive?
- Carbon dioxide
What are the top three most important nutrients for vines?
This nutrients are naturally present in soil.
What is chlorosis?
Chlorosis is a nutrient deficiency in the soil that affects the vine's ability to photosynthesize. A sign of chlorosis is yellow leaves and poor overall growth.
The usual cause for chlorosis is a lack of iron in the soil. Farmers will either add iron-rich fertilizers or plant iron-producing grasses as cover crops to treat the soil.
Vines go dormant at what temperature?
At what temperature can a vine freeze to death?
Dormant: 10°C (50°F)
Freeze to death: below -20ºC (-4ºF)
List a vine's annual cycle.
Budburst: early spring
First shoot/leaf growing: spring
Flowering: late spring/early summer
Fruit set: early summer
Ripening time: summer/late summer
Harvest: late summer/early autumn
What is the growing season for the northern hemisphere? And for the southern hemisphere?
Growing season for:
- Northern hemisphere: April - October
- Southern hemisphere: October - April
When does flowering happen?
- Northern hemisphere: May/June
- Southern hemisphere: November/December
What is the optimal weather during flowering?
Warm temperatures, plenty of sunshine, little or no rain.
Frost is most dangerous around which phase of the vine's annual cycle?
What are some adverse effects from frost?
Budburst is when frost is most dangerous (March/April in Northern Hempishere, Sept/Oct in Southern Hemisphere).
- if frost occurs right before budburst, it can delay budburst which means the grapes are at risk of not fully ripening before autumn;
- new plant material can freeze and die;
- spring frost damage can decrease the annual yield;
- fungal diseases can develop if the weather stays wet.
What is Coulure?
Coulure is poor flower set due to cold or rainy conditions or poor fertilzation. The flowers drop from the cluster, known as "shatter."
What is the term for poor or irregular fruit set due to cold or rainy conditions (it produces clusters with "hens and chicks")?
During the summer months, what vineyard management techniques help control the quality and ripeness of the grapes?
Green harvesting: dropping underdeveloped clusters right after véraison so the vine puts its energy into the remaining clusters;
De-leafing: removing leaves near the fruit zone so the grapes see more direct sunlight.
Véraison is the onset of ripening and when the grapes change color.
Red varieties turn from green to purple or black, and sugars increase while acidity levels decrease.
What vineyard work is done while the vine is dormant?
The vinegrower removes the previous year's shoots and cane(s) to establish next year's growth.
How does altitude affect grape growing?
As altitude increases, temperatures decrease.
Altitude is what allows some regions to exist closer to the Equator, e.g. Cafayate, Argentina which sits ~3,000m above sea level.
What natural factors influence the temperature/heat in a vineyard?
- Ocean Currents
- Soil structure
- Slopes and aspect
- Diurnal range
How can soil affect a vineyard's temperature?
Rocky, slatey soils - stony or dark in color - absorb heat during the day, and release it overnight.
- Galets roulés in Châteauneuf-du-Pape
- Blue Devonian slate in the Mosel
- Llicorella soil in Priorat
Which way do vineyards face in each hemisphere to ensure optimal sun exposure?
Vineyards in both hemispheres will face the Equator for optimal sun exposure.
Northern hemisphere vineyards will face south.
Southern hemisphere vineyards will face north.
What detrimental effect can drought have on a vine?
Drought can cause a vine to endure water stress which can potentially make the vine shut down (read: stop transpiration and photosynthesis).
What are the effects on a vine if its roots are generally around too much water (read: poor drainage, etc.)?
If a vine's roots become waterlogged or have excessive water available to it, a few things can happen:
- canopy overgrowth, which takes energy away from grapes so they won't ripen properly;
- bloated grapes, which dilutes flavors;
- roots can rot.
What sorts of damage can rainfall cause?
It depends on where the vine is in its annual cycle.
- disturb flowering and fruit set;
- encourage the development of fungal diseases;
- if right before harvest, rain can bloat berries and introduce grey rot.
What are the 3 most important irrigation systems used around the world?
1. Drip irrigation
3. Flood irrigation
Between clay, sand, and stone, which soil has the highest water retention?
Clay has the highest water retention capability of the three.
Sand and stony soils drain easily.
Besides clay, what soil element is known for good water retention?
Humus, which is organic matter made up of decomposing plant and animal materials.
What is the composition of loam soil?
Loam is a mixture of sand and clay. It has both good water drainage and retention due to its composition.
How many years after first planting a new vineyard will vines produce a usable crop?
The third year after planting.
How often is a vineyard typically replanted?
About every 30 to 50 years.
After 25-30 years, a vine produces less quantity but higher quality crops.
Is it common practice to leave a vineyard fallow for a few years after its vines have been uprooted?
Yes, it's common to leave a vineyard fallow for at least 3 years prior to replanting. This time off allows the farmer to work the soil and help it regain its nutrients so it can accept new plantings.
Name some vineyard pests other than phylloxera.
What are nematodes, and what damage can they cause to a vine?
Nematodes are microscopic worms that eat the roots of vines, leaving open wounds through which viruses are known to enter.
Nematodes spread one particularly damaging nepovirus that causes Fan Leaf Degeneration, which deforms shoot growth, leads to poor fruit set, and reduces yields. Affected vines must be removed, they cannot be grafted.
Name 3 fungal diseases.
Downy mildew (aka Peronospera)
Powdery mildew (aka Oidium)
- Grey Rot
How are Downy and Powdery Mildew controlled?
How can both be prevented?
Downy Mildew is controlled with Bordeaux Mixture, a blend of copper sulfate, lime, and water.
Powdery Mildew is controlled with sulfur or other fungicides.
Both can be prevented with canopy management. The more air circulation in the canopy, the less likely either mildew will appear.
What is the fungus that causes grey rot?
Botrytis cinerea is the fungus that causes grey rot.
Which one develops - the beneficial Botrytis or grey rot - really depends on the weather. If afternoons become sunny and warm, dissipating humidty and moisture in the air, Botrytis (Noble Rot) develops. However, if afternoons remain grey and soggy, grey rot takes hold and truly just rots the grapes.
Of the 3 following bacterial diseases that can affect vines, which today is the most pressing?
- Pierce's Disease
- Crown Gall
- Bacterial Blight
An insect called the Glassy-Winged Sharpshooter spreads a deadly bacterium, which lives in the plant's xylem and multiplies to such a size that it blocks the plant's ability to perform transpiration, rendering the vine incapbable of producing chlorophyll. It killls the vine within 1-5 years.
Many regions in the new world presently suffer from it, mainly in California and South America.
Describe sustainable agriculture.
- use of synthetic chemicals is restricted but not prohibited;
- spraying or applying chemicals only when needed;
- practicing Integrated Pest Management - introducing natural predators to control pests;
- creating biodiversity in the vineyard.
Describe organic viticulture.
- synthetic chemicals not allowed;
- the only real chemicals allowed are sulfur and copper, and their applications are restricted;
- if a winery wants to be certified organic, they must apply for accreditation with one of the certifying bodies and work their vineyard organically for at least 2 years prior to certification.
Describe biodynamic agriculture.
- Biodynamics is much more than a method, it is a spiritual science, a belief system — a holistic way of seeing and understanding the natural world that focuses on regenerative practices.
- Biodynamics sees the vineyard as an ecological whole: not just rows of grapevines, but the soil beneath them—an organism in its own right—and the other flora and fauna in the area, growing together interdependently.
- Where biodynamics differs from organic or sustainable agriculture is in its idea that farming can be attuned to the spiritual forces of the cosmos. This might mean linking sowing and harvesting to the phases of the moon or the positions of the planets.
Who are seen as the father and mother of biodynamics?
Rudolf Steiner, an Austrian philosopher, writer, social reformer, and esotericist. 1861-1925.
Maria Thun, a German researcher, farmer, and Steiner devotee. It is from her astronomy observations that we get today's root, leaf, fruit, and flower days. 1922-2012.
Image of a biodynamic vineyard.
Note the biodiversity in this vineyard and how happy the vines look.
(These vines are also cordon trained)
Image of a conventional vineyard.
Note the compacted soil, the crushed plastic cup, the difference in the color of the grass, and how the vineyard looks as though it were napalmed.
1 acre is approximately how many hectares?
1 acre = .4 hectares
Conversely, 1 hectare = 2.47 acres
What are the advantages of mechanical harvesting?
- efficient - berries are shaken from stems so there is no need for a destemmer;
- decreases number of laborers;
- can be done overnight which saves costs on lowering grapes' temperatures prior to processing them.
What are the advantages of hand harvesting?
- easier to control grape quality;
- usually less berry damage, therefore fewer oxidation issues;
- whole clusters are picked which keeps stems intact;
- In some places (usually steep and/or with terraces built centuries ago), handpicking is the only option, e.g. Mosel, Valtellina, Northern Rhône.
What is the tool used by hand harvesters?
A pair of secateurs (sekəˈtərz), or pruning shears.