Post-fermentation Operations

Question 1

What fining agent is generally used to fine high quality red wine?

Answer 1

Egg albumen

Question 2

What are clarification methods?

Answer 2

Sedimentation and racking
Fining
Filtration
Centrifugation
Flotation

Question 3

What other fining agent needs to be used in conjunction with casein for it to precipitate in wine when used to treat excess colour?

Answer 3

Tannin

Question 4

What is the only effective treatment of browning in wine due to laccase action?

Answer 4

Pasteurization

Question 5

Which of the following fining agent is most likely to cause protein instability (over-fining) if too much is used?

Answer 5

Gelatin

Question 6

What microbial spoilage can cause a wine to have a ‘ropy’ texture?

Answer 6

In wines with low acidity and low sulphur dioxide, lactic bacteria can give the wine a ropy texture

Question 7

What are methods to achieve tartrate stability?

Answer 7

Adding potassium bitartrate
Cold stabilization
Contact process
Adding gum arabic
Adding metatartaric acid
Adding calcium tartrate
Ion exchange

Question 8

What is copper casse?

Answer 8

A reddish-brown haze and deposit that forms in white wines with more than 1mg/L (instability)
Does not occur straight away

Question 9

What are methods to prevent copper casse?

Answer 9

Bentonite fining: reduces level of unstable protein
Addition of gum arabic: protective effect
Blue-fining (potassium ferrocyanide treatment)