Unit 3 - Lesson 4 - Grapes

Question 1

Difference between molasses and grapes

Answer 1

Molasses can store in drums need to use grapes

Question 2

For unaged brandy what type of grape?

Answer 2

Focus on aromatic grapes

Question 3

What is the difference between storing molasses and grapes?

Answer 3

Molasses can be stored in drums for months

Grapes only two weeks

Question 4

What is the Crush pad

Answer 4

Name give to winery’s grape processing operations

Question 5

Hand harvest versus mechanize

Answer 5

Hand is expensive but selective

Higher upfront costs, less discriminant

Question 6

Why remove stems? Why not remove stems?

Answer 6

Stems - have tannins that are not attractive

However, stems contribute to mouthfeel and some flavors

Question 7

Where does destemming typically take place?

Answer 7

On the sorting table (some are mechanized)

Question 8

Describe machine destemmers

Answer 8

Use rubber rollers made of nylon or rubber

Rolles just enough to break the skin without pulverizing

Question 9

What determines choice of destemmer?

Answer 9

The distillers requirement for throughput

Large requirement means mechanized

Question 10

3 types of grape press

Answer 10

Basket or ratchet press
Bladder press
Continuous Screw Press

Question 11

Describe Basket Press

Answer 11

Baskets on top of metal plate
Screw down the middle with a top plate
Grapes load and top is "ratched" down the screw pressing the grapes
Holes in the basket let juice drip
Very simple NO ELECTRICITY

Question 12

Challenge for Basket/Ratchet Press

Answer 12

Too much pressing breaks seeds and cause “green flavors”

Question 13

Describe Bladder Press

Answer 13

Common for Brandy
A large perforated cylinder with inflatable membrane down the middle
Bladder expands from middle, pressing grapes against the cylinder and juice is collected

Question 14

Why are Bladder presses popular?

Answer 14

1. Easy to operate - little physical labor
2. Programmable - eg to the correct pressure
3. Gentler on grapes without sacrificing juice yield

Question 15

Describe a Continuous Screw Press

Answer 15

Horizontal and perforated
Grapes feed while screw is moving pushing them forward increasing pressure on them as they go
Pushes pomace to the end which is ejected
Fed a continuous stream of grapes

Question 16

1st run grape juice

Answer 16

Free run - requires little pressure

Question 17

Why dont Brandy makers separate press fractions of wine (eg Free Run vs Pressed)?

Answer 17

Tannins are not a concern since they are not volatile

Question 18

Drawbacks for a Bladder Press

Answer 18

Expensive
Requires specialize hookups
Large

Question 19

What is a continuous screw press?

Answer 19

horizontal cylindrical chambers with perforations throughout
Large screw through middle
Feed continuous stream

Question 20

Problem with screw press?

Answer 20

force on the fruit. Therefore, if the press operator is not paying attention, the machine can add green flavours and unwanted tannins to the juice.

Question 21

Solid portion of grapes

Answer 21

amounts to 30-35% per volume ofgrapes. For instance, if we have 1000 L ofgrapes,we will have between 300-350 L of grape solids. Our press should thus be sized to handle 3.5 hL.

Question 22

What do brand makers like

Answer 22

This initial juice fraction usually contains lower levels of tannins than the other fractions.
Brandy distillers do not generally separate press fractions like this; tannins are not much of a concern as they do not volatilise in the still very easily.

Question 23

1 Ton of grapes yields

Answer 23

600-680 liters of juice

Question 24

What is good about cumbling

Answer 24

Crumbling is when the press retracts the pressure on thegrapes. The press operator can break up the pressed skins by hand. Alternatively, the press rotates on its axis and breaks the grape skins up, and then shuffles them. When the press turns back on, more juice can be extracted more evenly.

Question 25

YAN

Answer 25

YAN is a measure of the primary amino acids, ammonium ions, and peptides present.