16.2 White Winemaking: Pressing the Grapes

Question 1

When is pressing typically carried out in white winemaking?

Answer 1

before fermentation

Question 2

What is the goal of pressing?

Answer 2

to separate the skins from the juice

Question 3

Why is it important to press extremely gently in white winemaking?

Answer 3

avoid the extraction of unwanted compounds from the skins and seeds of the grapes (tannins, colour)

Question 4

What are the two options for pressing/destemming white wines? Which is more common?

Answer 4

1. Grapes are destemmed and crushed before being loaded into the press (typical)
2. Whole bunches of grapes are pressed

Question 5

To reduce the risk of oxidation during pressing, what might be done?

Answer 5

• Whole bunches of grapes are pressed

- Inert gases (e.g. nitrogen, carbon dioxide, dry ice (carbon dioxide in solid form)) used within the press

Question 6

What are the advantages of whole bunch pressing?

Answer 6

• reduces risk of oxidation
• gentler (results in juice low in solids, tannins, color)
• stems help to break up the mass of grape skins, providing channels for the juice to drain

Question 7

What are the disadvantages of whole bunch pressing?

Answer 7

• grapes must be hand-harvested

- whole bunches take up a lot of room in press (fewer in each press cycle)

Question 8

For what types of wines is whole bunch pressing common?

Answer 8

Smaller batches of premium wines

Question 9

What is free run juice?

Answer 9

• Juice that is drained off as soon as the grapes are crushed (must be destemmed first)
• Juice that is lowest in solids, tannins, and colour
• Can be used exclusively to make a wine (costly, reduce volume)

Question 10

What is press juice? How does it compare with free run juice?

Answer 10

• The juice that runs off through the pressing
• At first, similar to free run juice
• As the pressing continues and more pressure is applied, more solids, tannin and colour are extracted

Question 11

When it comes to acidity and sugar, how does the free run juice compare to the press juice? How does this affect the final wine?

Answer 11

Press juice

• lower acidity
• less sugar
• Makes wines that are fuller bodied

Question 12

What are ‘press fractions’? Describe the last press fraction?

Answer 12

• winemaker may decide to separate the press juice into different fractions as the pressing continues
• different press fractions may be blended later
• last press fractions are likely to be too astringent or bitter (due to phenolic compounds from the skins, seeds or stems), may be discarded