Introduction to Winemaking Part 6: White Wines

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Introduction to Winemaking Part 6 White Wines
Dr. James Harbertson Extension Enologist Washingto
n State University
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White Winemaking Techniques

• Cool Fermentation
• Protection from oxidation
• Minimization of skin and seed contact time
• Direct to press
• Enzyme addition
• Barrel Fermentation
• Tank Fermentation
• Secondary Fermentation
• Dry or Sweet
• Blending

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Cool Fermentation

• Most whites are fermented at low temperatures (13
  to 21?C)
• Minimizes loss of volatile flavor compounds that
  can occur with rapid CO2 generation.
• Fermentation is generally longer and slower
  because of low temperature and lower yeast
  nutrient (pulp, skins and seeds absent).
• Cool temperatures slow oxidative reactions

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Protection from Oxidation

• Oxygen is necessary component for browning
  reactions
• Browning occurs when a grape enzyme reacts with
  phenolic compounds found in pulp, skin and seed
  and oxygen to produce brown compounds.
• Minimize skin and seed contact, press early or
  skip crushing and go direct to press
• Minimize oxygen exposure
• Add SO2 to inhibit enzyme activity
• Keep temperature low to slow reactions

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Barrel Fermentation

• Temperature is fairly low- small volume allows
  good heat dissipation
• Extraction of barrel components (vanilla and
  toast characters are desired). (Age of barrel
  matters)
• Undergo ML in barrel and gain buttery and creamy
  aspect.
• Can age on lies longer 6 months to year to gain
  yeast characters (sur lies aging)

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Dry or Sweet?

• Fermentation to dryness or arrest fermentation to
  leave residual sugar (RS)
• Arrest Fermentation
• Lower temperature to 5 ?C
• Centrifuge
• Sterile Filtration (0.45 micron pore filter)
• Late Harvest grapes
• Moldy grapes
• Blend with concentrate

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Botrytis

• Botrytis cinera is a mold that attacks grapes
  (noble rot)
• Under right conditions (high humidity, cracked
  grapes) the spores will germinate
• Grapes lose water without gaining raisin flavor
• Acidity does not change a lot
• Yields grapes with high brix (30 and above)
• Concentrates grapes flavors, mold character
• High production costs for artificial innoculation

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Blending

• Keeping lots separate gives greater options
• The same or different varieties can be blended
• Where science and art intermingle (The whole is
  often greater than the sum of the parts)
• Allows for larger volume of more uniform wine and
  complex wine.
• In practice small scale blends made up and tasted
  and s refined.

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Tank Fermentation

• Allows good temperature control
• Control of oxygen exposure
• Temperature can be dropped to arrest fermentation
  for sweet wines
• No oak components
• Better control of ML
• Steel barrels can also be used

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White Wine Styles

• Dry White Wines
• High Acid Generally Cool Climate
• Full-Bodied, Wood Aged White Wine
• Barrel Fermented
• Aromatic White Wine
• Can be sweet

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France as Example

• France will be used as a model to demonstrate
  different wine styles and winemaking techniques
• Different regions of France will be discussed
• Details of legal system will be omitted
• Burgundy and Bordeaux will be discussed for
  whites and Rhone will be added for reds.

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White Burgundies

• Cool Climate
• Chardonnay
• Dry White (apple, pear) with oak and ML character
• Chaptalization
• High Acid
• Barrel Fermented/wML
• Oak Aged
• Sur Lies Aging

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Chablis

• Cool Climate with best vineyards chalk and clay
  soil.
• Chardonnay
• Dry White apple, pineapple with mineral
  character flavors
• Use steel jacketed tanks to control fermentation
  temperature.
• Some are aged in old oak vats post ML or only in
  steel tanks.

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White Bordeaux Wine

• Primarily Sauvignon blanc with Semillon
• Sauvignon blanc is dry with grassy-vegetal
  aromas, also fruity.
• Semillon is dry with honey and candied fruit
  aromas.
• Semillon is blended with Sauv. blanc to add body
  and age-ability.

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White Bordeaux II

• Fermented in Tank with temperature control
• Fermented to dryness No ML
• Protected from oxidation
• Stored in old oak tanks or steel tanks
• Blended to taste

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Sauternes

• Sauvignon blanc and Semillon (mostly Semillon)
• Botrytis infected sweet wines
• SeasonalHigh humidity to encourage mold growth
  followed by dry period for shriveled berries.
• EtOH ranges from 12-14 while RS ranges from
  5-15
• Golden wines age well with flavors of apricot,
  peach, pineapple and vanilla.