13.8 General Winemaking Options: Post-Fermentation Adjustments

Question 1

What adjustment can be made after fermentation?

Answer 1

• Acidity
• pH
• Sweetening
• Removal of alcohol
• Colour

Question 2

Why must only small adjustments be made post-fermentation?

Answer 2

Must be careful to not upset the balance of the wine

Question 3

Why adjust alcohol after fermentation?

Answer 3

• to produce a reduced alcohol wine (e.g. below 5.5 per cent)
• to adjust the level of alcohol marginally

Question 4

What is the simplest way to marginally adjust the level of alcohol after fermentation? What is the downside?

Answer 4

• Add water

- Reduces the intensity of flavour

Question 5

Describe two ways to reduce alcohol post fermentation (not dilution).
Which is most common?

Answer 5

1. Reverse osmosis (*most common)
   - cross-flow filtration
   - removes a flavourless permeate of alcohol and water, which can be distilled to remove the alcohol.
   - permeate is blended back to recreate the wine.
   - equipment rented or bought - costly.
2. Spinning cone
   - a device first extracts volatile aroma compounds from wine then removes the desired % alcohol.
   - flavour components blended back.
   - This technology is only financially viable for large volumes of wine.

Question 6

In the EU what post-fermentation alcohol reduction methods are permitted?

Answer 6

Within specified limits:

• Reverse osmosis
• Spinning cone

Question 7

What post-fermentation color-altering techniques may be used? Where is this not permitted?

Answer 7

• Fining: reduce unwanted colour tints
• Add MegaPurple: grape-derived colouring agent, used to enhance color intensity in a red wine.
• not permitted in Ribera del Duero