Viticulture and vinificaiton for dummies

Viticulture is the science, production and study of grapes. It deals specifically with grapes used in a vineyard. 

To gain a proper understanding we must first look at the grapes life cycle. 

  • The vine begins in spring with ‘budbreak’
  • ‘Flowering’ occurs 6 – 13 weeks after budbreak
  • Following budbreak is the self pollination which lasts 10 days and leads to the ‘fruit set’
  • Successfully pollinated embryos grow into bunches
  • In January/February veraison occurs – sugars are moved from the leaf system to the fruit
  • Once the optimum level of acidity is reached then it is time for harvest

 

Budbreak  – September

Flowering – November

Fruit set – November

Veraison – Jan/Feb

Harvest – Feb – April 

 

Terroir – this looks at the environment around the vineyard

Macroclimate: the regional climate

Mescoclimate: climate of a particular climate i.e. aspect (degree of slope), shelter of vineyard, slopes etc

Microclimate: restricted space around the vine, techniques of canopy management have been adopted to increase/decrease exposure to sunshine

1)   Winter pruning

2)   Leaf removal

3)   Shoot positioning

4)   tresilling systems

 

Soil Type

  • Low fertile soil produce better wines then rich soils
  • The vine should always struggle to produce good fruit
  • Well drained, easily penetrable soils, with good water retention. This allows the vine to dig deeply for water and minerals
  • High Ph in soil contributes to higher acidity

 

Clones

  • Clones are identical genetic reproductions of a single vine, they are chosen because of their disease resistance, hardiness, yield and aromatics
  • Mass selection a grower will attempt to take the budwood as well as all the positive traits and eliminate the negative traits

 

Vine training and pruning

The purpose of vine training, pruning etc is to maximize the vines performance in local conditions as well as keeping the canes from touching the ground and establishing new roots

 

Cordon trained – vine has at least one permanent cane that extends from the trunk called the arm and is supported by the tresil

 

Head trained – trunk ends in a knob and is generally free standing

 

Guyot system – vertical trellis on which canes can be suspended. One spur and 2 year old cane

 

Goblet system – southern Rhone, southern Italy, unsupported and resembles a goblet extending from the spur

 

Cordon de royal – pinot in champagne

 

Vine disease and insect threats

Fungal disease – manifest as mildew or mold. Warm damp climates attack the root system or canopy

 

Bacterial – devastating and hard to control the spread.

 

Sustainable models of viticulture

American or Australian wine is listed as organic it must be produced from organically grown grapes and have no added sulfites

 

Biodynamic: homeopathic preparations produced from such animal and mineral substances. Follow the lunar cycles and have very minimal intervention with the vines

 

Vinification

  • Alcoholic fermentation – yeast cells convert sugar in grapes into ethyl alcohol
  • A small amount of sulfur is produced naturally and some is added
  • Acetic acid + alcohol = volatile acidity
  • White wines generally take place at a cooler fermentation so that fruit and freshness are preserved
  • Red wine will ferment in a hotter environment to maximize tannin, color extraction and flavor
  • Barrel fermentation – lacks temperature control
  • White grapes that are barrel fermented will lose some initial fruit but gain more oak expressions
  • Barrel fermented wines are generally subject to the process of lees contact and batonnage which adds further complexity
  • Cultured yeast promises reliability and can work in higher levels of alcohol then ambient yeasts
  • Adding sulfur and cultured yeast will give winemaker control

 

Malolactic fermentation

  • secondary fermentation may take place in the wine, this is where lactic acid bacteria convert harsh malic acids into softer lactic acids and carbon dioxide

 

Carbonic maceration

  • used for some red wines where whole uncrushed grapes in an anaerobic environment. The wine will be filled with whole berries at the bottom are crushed beaneth the weight from above, fermentation takes place. i.e beaujoulais noveau

 

Red wine production

  • grapes are placed on a conveyer belt so the winemaker can get rid of any unwanted material
  • the fermentation of whole berries which is a common practice among pinot noir and syrah. Stems may add a spice, complexity and structure
  • a cold soak for red promotes the extraction of color and tannin. Grape skins are always included in red wine fermentation as the wine maker hopes to extract the phenolics
  • remontage which is where the wine is pimped over the cap, this will agitate and aerate the wine to a great degree

 

White wine production

  • white wine grapes are crushed and pressed prior to fermentation, after pressing the juice is allowed to settle and solids are racked off.
  • The fermentation occurs at a cooler temperature for white. They are often clarified after fermentation.
  • Cold stabilization – causes tartrate crystals to precipitate out of a wine.
  • White wines may be stored in barrel or steel vat. 

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