13.4 General Winemaking Options: Pressing

Question 1

When are grapes typically pressed in white winemaking?

Answer 1

almost always pressed to extract the juice from the grapes and to separate the skins from the juice before fermentation

Question 2

When are grapes typically pressed in red winemaking?

Answer 2

• crushed before fermentation

- pressed after the desired number of days on the skins or at the end of fermentation

Question 3

What are the 4 main types of presses? Which is more popular?

Answer 3

1. Pneumatic presses (more popular)
2. Basket presses
3. Horizontal screw press
4. Continuous press

Question 4

Describe how a pneumatic press works.

Answer 4

• The press is made up of a cylindrical cage with a bladder that runs down the side or middle of it.
• Grapes are loaded into the tank (on one side of the bladder).
• The other side of the cage is filled with air and, as the bladder inflates, the grapes are gradually pushed against grates on the side of the cage, separating the juice or wine from the skins.

Question 5

What are the 2 main advantages of pneumatic presses?

Answer 5

1. Can be programmed to exert different amounts of pressure (light pressure for less extraction, harder pressure for greater extraction, which can provide different blending components if needed)
2. Can be flushed with inert gas before use to protect the juice or wine from oxidation

Question 6

In what types of wineries are pneumatic presses common?

Answer 6

Medium to large-scale wineries that can afford the initial investment

Question 7

What is another name for a pneumatic press?

Answer 7

Air bag press

Question 8

Describe how a basket press works.

Answer 8

• A ‘basket’ is filled with grapes and pressure is applied from above.
• The juice or wine runs through gaps or holes in the side of the basket and is collected by a tray at the bottom of the press.
• A pipe transfers the juice or wine to another vessel.

Question 9

What is the main advantage of basket presses?

Answer 9

• Believed to be gentler than pneumatic presses

Question 10

What are the main disadvantage of basket presses?

Answer 10

• hold a smaller press load,
• much more labour intensive
• not sealed vessels, cannot be flushed with inert gases to avoid oxygen exposure

Question 11

In what types of wineries are basket presses common?

Answer 11

small wineries making premium wines

Question 12

What are 2 other names for a basket press?

Answer 12

‘vertical press’ or ‘champagne press’

Question 13

What is a horizontal screw press?

Answer 13

• Similar to a basket press mounted horizontally above a rectangular draining tray
• Less gentle, time-intensive, less popular

Question 14

What is a continuous press? What types of wines is it best suited for?

Answer 14

• Allows grapes to be continually loaded into the press as it works by using a screw mechanism;
• Quicker pressing of high volume
• Less gentle
• Best for: high volumes of inexpensive wines.

Question 15

How do most modern presses work?

Answer 15

• Computerized

- Winemaker can program the pressure and length of time

Question 16

What does less pressure during pressing mean for the final wines?

Answer 16

Will extract less tannin and colour from the skins, but will result in a smaller volume of juice/wine

Question 17

What does a longer press cycle mean for the final wines?

Answer 17

Extends the contact between the skins and the juice/wine, which extracts more aroma/flavour and tannin

Question 18

What is pomace?

Answer 18

The solid remains of the grapes left after pressing