No and Low-Alcohol Winemaking

Question 1

How are they made

Answer 1

By producing wine then dealcoholizing it

Question 2

Early methods

Answer 2

• relied on heat-induced evaporation as alcohol boils at lowers temperatures than water
• wine had to reach 78C / 172F which caused cooked flavors and loss of essential volatile aroma compounds
• created an association with low quality

Question 3

Modern methods

Answer 3

1) membrane separation technique (reverse osmosis)
2) thermal distillation (vacuum distillation & spinning cone)

Question 4

Pre-fermentation options to lower alcohol/ fermentable sugars in the grapes

Answer 4

1) grape varieties that accumulate low levels of sugar (Sauvignon blanc, Riesling)
2) cooler site selection
3) vineyard management to reduce photosynthesis
4) early harvest
5) blending in less ripe grapes
6) dilution of must with water (when legal)
7) filtration of must such as reverse osmosis before fermentation (may remove color/ volatile aromas)

Question 5

Fermentation options

Answer 5

1) non-saccharomyces yeast strains can be used to ferment less sugar into alcohol (ex: Metschnikowia pulcherrima can produce wine with reduced ethanol)
2) interrupt fermentation via chilling

Question 6

Reverse osmosis

Answer 6

A membrane separation technique that removes flavorless permeates of alcohol and water, which can be distilled and added back. Most common option. Best for minor alcohol adjustments.

Question 7

Vacuum distillation

Answer 7

A thermal distillation technique that occurs in a vacuum to lower the boiling point to 48C / 118F to limit the loss of volatile aroma compounds

Question 8

Spinning cone

Answer 8

A thermal distillation device that spreads the wine out to a very thin film. First volatile aroma compounds are extracted then alcohol, aroma compounds are blended back in. The only financially viable option for large volumes of wine.

Question 9

Effects of dealcoholization

Answer 9

1) loss of volatile aroma compounds
2) concentrates phenolic compounds
3) reduces body
4) reduces aromatic intensity
5) increases acidity
6) less stable (additional steps like pasteurization/ DMDC needed)
7) shorter shelf life (1-2 years)
8) cost increase as production is more steps with 15-30% loss of yield

Question 10

Post-dealcoholization adjustments

Answer 10

1) sugar
2) flavor enhancements
3) tannins
4) glycerol

Question 11

Labeling requirements

Answer 11

Low alcohol - 1.2% or less
Non-alcoholic - 0.5% or less
Alcohol free - 0.05% or less

Highly dependent on where it is being sold