Introduction to Winemaking Part 6: White Wines

Dr. James Harbertson

Extension Enologist

Washington State University

• 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

White Winemaking Techniques

Cool Fermentation

•Most whites are fermented at low temperatures (13 to 21C)

•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

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

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)

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

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

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.

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

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

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

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.

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.

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

Sauternes• Sauvignon blanc and

Semillon (mostly Semillon)• Botrytis infected sweet

wines• Seasonal:High 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.