D1.C15. Finishing and Packaging Flashcards
What should the wimemakers do, to produce a clear and stable wine?
Wines should be clarified and stabilised before being bottled and packaged
Name the practices used for the clarification of the wine.
- Sedimentation
- Centrifugation
- Fining
- Filtration
Number of rackings required depend on which factors?
- Shape of the container: The larger the storage vessel, the greater the number of rackings required to avoid a thick layer of sediment
- Volume of the wine
- Available labour
Why do some of the wines are clarified only by sedimentation?
Some winemakers believe that clarification by sedimentation avoids the potential loss of texture and flavour that may occur if the wine is fined or filtered
Why sedimentation is usually only suitable for premium or super-premium priced wines?
As sedimentation takes time, this has a cost
In which condition, sedimentation happens as a part of the process?
Barrel aging
In many cases, why will the winemaker accelerate the process of clarification?
In high volume production the speed of processing wine is financially important
Centrifugation can be a substitute for…
Depth filtration
When is centrifugation advantageous?
For the wines with a lot of matter in suspension
Why is centrifugation practiced only in high-volume wineries?
Because of the cost of the machine
What are the origins of fining materials?
- Protein
- Mineral
What is the aim of fining?
- To remove a small proportion of unstable colloids (microscopic particles too small to be removed by filtering) from the wine
- Clarify the wine
- Stabilize the wine against the formation of hazer later in the bottle
What do winemakers do, before using fining agents? Why?
- They conduct laboratory trials before using fining agents to ensure that the minimum effective amount is used
- Many fining agents can remove desirable compounds from wine or make the wine unstable when too much is added (over-fining) and therefore it is important to add
only the minimum effective amount
What are the solutions that fining agents can offer other than clarifying the wine?
- Removal of harsh tannins in red wine
- Correction of browning in white wines
Name the 3 categories of common fining agents.
- Those that remove unstable proteins
- Those that remove phenolics that contribute undesirable colour and bitterness
- Those that remove colour and off-odours.
Why is removal of unstable proteins not needed for red wines?
- They bind with tannins, precipitate naturally and are removed when the wine is racked
What happens if the proteins in the white and rose wines are not fined?
They can agglomerate into a visible haze if warmed up
Which fining agent is used to remove unstable proteins?
Bentonite
What is bentonite?
It is a form of clay
What is the advantage of bentonite?
It has a minimal effect on the flavour and texture
What are the disadvantages of bentonite?
- It leads to some colour loss in red wines
- Produces large amounts of sediment, and so wine is lost when it is racked off
Name the fining agents that remove phenolics that contribute undesirable colour and bitterness
- Egg white
- Gelatin
- Caseine
- Isinglass
- Vegetable protein products
- PVPP ( Polyvinylpolypyrrolidone)
What re the pros and cons of egg white?
- Pro: It is gentle to the wine
- Con: It is an allergen, not suitable for vegan wines
What are the effects of gelatine on wine?
- Aids clarification
- Removes bitterness and astringency in red wines
- Removes browning in white wines