CSW Chapter 4 Viticulture

Grape vines cover 19M acres and produce 70M tons of fruit. 70% goes into wine. 30% into all else.

What is viticulture?

The aspect of agriculture that deals with thecultivation of grape vines. Practiced for thousands of years

What are the Trunk, Arms, Spurs, Canes, Cordons and Canopy of the grape vine

Trunk is central vine.

Arms are the one or two branches off either side

Spurs are young/small canes (most of which are removed

Older, Thicker Canes become Cordons

The Canopy is the leaves and grape bunches which grow seasonally

What is purpose of a grape

To protect the seed with fresh that nourishes it while it matures. Protecting it with green camouflage that is too acidic to taste good to predators when young, but when ripe turns an attractive color with lots of sugar that encourages predators to eat it and spread the seed.

How long for a new vine to produce grapes. To produce good grapes

Production of some grapes in year 1-2 but those are removed to concentrate on vine development. Year 3 (third leaf) is generally the earliest to start using the grapes for fine wine. Year six optimally. 20 years plus and the vine losses some vigor, but quality goes up. 50year + is oldW vine. Smaller, fewer grapes, more concentrated flavor.

What is weeping? in a vine life cycle

above 50degrees F the sap begins to flow upward from the trunk to the arms to the tips of the canes. Lasts 1 day. a few days before Bud break

What is bud break? (In vine lifecycle)

When the first shoots of buds emerge from the tips of the branches. Critical time when buds are very venerable to frost. Late frost can damage the harvest.

What is flowering in the vine lifecycle?

40 -80 days after bud break, tiny clusters of flowers appear at intervals along the shoots. Each flower that is fertilized will form the foundation for a grape.Warm weather is idea. Rainy/windy weather can interfere.

What does it mean that Vinifera is a self-pollinating plant.

It means bees and insects are not necessary to polinize as the breeze blows pollen from one plant to the next.

What is berry set or fruit set and what is Colure?

The point at which the berries become grapes. Colure (shatter in English) is a malady that interferes with Fruit set , like Millerandage. The result is a large collection of seedless berries mixed in with the regular ones.

What is Veraison in the life of the plant

Veraison signals the sudden acceleration of growth toward maturation. Happens about 1.5 months after fruit set and then just take off! Most noticeable in red grapes which take on red hue at that time.

When is Harvest in the lifecycle

Generally 1.5-2months after Veraison when grapes are ripe in terms of both sugar levels. Physical and Phenolic maturity.

How long from Bud Break to Harvest

Generally 140-160 days but can be as short as 110 or as long as 200

What do cold nights of autumn mean to the vine.

That it should withdraw sap from the extremities and drop leaves and enter dormancy. That is when the grower will prune removing most of the years growth to prepare for the next year.

What are the 4 metabolic process for a grapevine

Photosynthesis, Respiration, Transpiration and Translocation. These processes have a direct impact on quality.

What is photosynthesis.

The conversation of a clorophyl containing plant using sunshine to convert water and Co2 into sugars that form the building blocks of the vine. The rate of sugar production is a direct result of photosynthesis and photosynthesis is driven by sun and warm temperatures (50degrees+)

What are ideal conditions for photosynthesis

Max Sun = long days, clear days, minimal shading, southern facing AND warmth.

What is Respiration in a plants metabolic cycle?

When a plant breaks down sugar and related carbohydrates to release the energy for use in building the leaves and root growth. During Veraison and when sugar is not available the plant breaks down Malic acid for energy thus Malic acid drops as grapes reach maturity.

Occurs throughout the growing season but every 18degree increase in temp doubles rate of respiration. Warmer it is, faster the acid level drops so cool nights which minimize acid loss, are key to good growing conditions - think Terlano

What is Transpiration in a plant’s metabolic Cycle

Analogous to perspiration in people, it’;s when water evaporates through openings in the underside of the leaf called stomata. Closely linked to weather - hot/sunny/windy days promote, the opposite does not. If the plant can not get enough water from it’s roots it will be cease transpiration and the stomata closes when means no more photosynthesis either.

What is Translocation in a plant’s metabolic Cycle

The process of moving sugars from where they are produced in the leaf tips to where they are needed in the growing shoots to promote development. Sugars not needed will be stored in the grapes or the stems.

What are the elements of Terroir?

Climate, Soil, Sunlight and Water

What is the difference between Climate and Weather?

Weather is the actual medioalogical conditions experienced and climate is the historical average of weather in a given place. Climate is the expectation and weather is what actually happens.What

What is the difference between the Macro-Climate, Mesoclimate and Micro-climate.

Macro Climate is the overall region, the Meso-climate is a specific portion of the region, the micro-climate is a small portion of the vineyard. Sometimes even a few rows.

How does temperature affect viticulture?

Temperature affects the sugar/acid balance in the grapes because as temps rise the acid consumption speeds up and can result in a poor quality sugar-acid balance. Cold at bud break can damage a vine as an early frost can too

How does Preciptiation affect viticulture?

Vines need 20-30 inches of rain/year. Rain is bad at harvest as it swells the grapes, diluting their sugar.

How does Humidity affect viticulture?

High humidity can promote fungus and mold which can degrade the grape quality or require fungicide.

How does Fog affect viticulture?

Fog can be good or bad. It mitigates sun which can be good in warm areas and bad in cold. Fog can also promote humidity/mold but then mold is useful when it’s botrytis cinera.

How does Wind affect viticulture?

A strong wind can disrupt the season, particularly by interfering with pollinating. In regions with high winds their are specific methods of Trellising and pruning to manage them.

How does Soil affect viticulture?

Less fertile soil is the key to good wine. Highly fertile soil promotes excess growth of shoots and bunches. With flavor and sugar components diluted across too many berries. Less fertile soil encourages vines to produce less vegetation and fewer grapes concentrating quality. This is why wine historically was farmed in places where food couldn’t be,

What are the two most important aspects of a top quality vineyard.

Good draining and poor nutritional value. Draining prevents mold and forces the vines to work for the water such that they don’t produce a lot of extraneous growth. Poor nutritional value does the same.

What are the four sizes of soil particles?

Clay (tightly packed), Silt (intermediate size) Sand (relatively little water retention) Gravel (large pieces of inert material)

What are the 3 types of climate and what do they refer to?

Maritime Climate is coastal with high rainfall and mild temps. Continental climate is drier with bigger seasonal temperature swings and Mediterranean is Warm, dry summers and low humidity with mild, wet winters. Med Climates are associated with high pressure atmospheric cells found over large oceans, that pulls rain in during the winter and keeps things dry and cool in the summer.

What is a marginal climate

A very short growing season with potentially cold winters that is difficult for grapes to come to fruition in.

What is a viral disease (in Viticulture)?

A disease spread though the process of propogating the wines via cuttings

What is a Bacterial disease (in Viticulture)?

Spread by insects and animals that carry microbes. Insects can feed on sick vines and transmit to healthy wines. Generally mitigated with insecticide.

What is a Fungal disease (in Viticulture)?

These are generally passed through airborne spores and are a real problem in moldy conditions. Fungus is fought with commercial herbicide or Suplhur. Two of the worst disease and Powdery mildew and Downy mildew

What is Botrytis?

A fungus that can be beneficial when making desert wines. If the fungus lands on fully ripe grapes it sends its filaments through he grape extracting water and leaving concentrated flavors and sugar behind and adding it’s own unique flavor which is described as being similar to honeysuckle. Ideas conditions for it are foggy mornings to create humidity and encourage the fungus and then sun afternoons so it doesn’t ravage the crop.

What is Phyloxera and why is it significant.

A small louse native to the Eastern US that kills of the vines on which it feeds. Travelled to Europe and then to Australia and eventually to the west coast of the US killing everything in its path. Eventually growers experimented with creating hybrid grapes with phyloxera resistant Vitis Labrusca but the results weren’t impressive. Eventually they discovered grafting and the vineyards were replanted. If phylloxera is in your vineyard there is no modern way of removing it.

What is the nematode?

A roundworm that feeds on the vines roots causing direct damage and sometimes transmitting viruses which can kill the vine. The problem is made worse with shallow rootstocks or drip irrigation which causes the roots to remain shallow and exposed to the roundworm.

What are spur and Cane pruning?

Spur pruning is when you train the vines to create one or more permanent cordons each of which will support several canes. Cane pruning is when the growler removes all but a left and right cane which are attached to a horizontal trellis.

What is Vine Training/Trellising

Because a vine has no central trunk, preferring to climb over things, it must be trained in which direction to grow and the growth managed to ensure the correct balance between vine vigor and quality of fruit expressed through desired yield per acre.

What is the Guyot method

A means of trellising in which one or two cordons from the vine are trained along a wire. Also known as VSP - Vertical Shoot Positioning. The new shoots grow upward braced by the trellis wires and the fruit hangs below in bunches. Great light exposure and air circulation as well as ease of harvest for mechanical harvests.

What is a divided Canopy?

In a high vigor area a vine might have two or more separate fruiting zones (Horizontal or Vertical) Examples include Geneva Doubt Curtain, Lyre, and Scott Henry Systems

What is a Bush Vine (Syn. Goblet-Style or Head Trained)

A vine that has a free-standing trunk, often gnarled, and spur pruned. with no artificial support.

What is a Pergola System?

A trellis where the fruit climbs up the vertical supports and spreads Horizontally allowing the fruit to hang.

What is Canopy management?

The process of managing the growth of shoots and clusters to optimize for a specific outcome. Shoot Thining, Shoot positioning, leaf removal, etc

What is Brix

Brix is the amount sugar in a grape, measured in “degrees Brix”. Measurements taken with a refractometer or (older) a hydrometer. Estimate of potential ethanol is roughly 5/9 of Brix so 27Brix would be 15% alcohol. 24 Brix would be 13.3% alcohol (if fermented dry) Other Countries use other methods, like Baume a unit of measurement (per 100ML of liquid) in France, or Oechsle in Switzerland and Germany.

Who designates “organic” status in the US?

The Department of Agriculture’s NOP or National Organic Program. There are other programs in other countries but US does not recognize them.

When are certain (inorganic and and manufactured) chemicals allowed in Organic Farming?

1. If there is no acceptable substitute (Sulphur)

2. If a chemical has been shown to have no adverse effects

What is Integrated Pest Management

A close up look at all the charecteristics of the given pest and a solution targeting said pest without a lot of collateral damage from a more far reaching chemical option.

Who invented Biodynamic wine

Rudolph Steiner