Fining And Clarification Flashcards
What are colloids
Small proteins in wine. When stable they are positively charged and cause no harm to the wine. As the proteins age they lose their charge and clump together, thus becoming big enough to cause haziness.
What is the difference between fining and filtration?
Fining takes place on a much smaller scale and uses chemical reactions (attraction between opposite electric charges) to remove unwanted particles, rather than physical barriers.
Give 5 examples of fining products
1) albumin (purified powder form of active ingredient in egg white)
2) egg white
3) casein
4) isinglass
5) bentonite
6) gelatine
7) tannin
8) silica sol
9) polyvinylpolypyrrolidone (pvpp)
10) activated charcoal
Which fining agents are suitable for red wine (3)
Bentonite
Albumin
Gelatine
Which fining agents are suitable for white wine (6)
Bentonite Gelatine Isinglass Casein Pvpp Silica sol
Which agents are suitable for removing tannins
3/4
Egg white/ albumin
Gelatine (more globally it removes phenolics)
Isinglass
Casein
Which fining agents might you use for clarity in wine(as well as removal of tannins)
Isinglass. A gentle fining agents. It is a pure form of gelatine.
What is casein useful for?
Decolorisation of white wines
Explain how you would use tannin as a fining agent
It’s not the same tannin that is naturally found in wine. It is a lot harder and more stringent. It is used in conjunction with gelatine. It precipitates out with the gelatine quickly, taking the colloids with it.
Of the gelatine based fining agents, which strips colour the least?
Isinglass. A draw back of it is that it becomes sticky and can make racking tricky
What is the most widely used fining agent
Bentonite. Only one that it’s not a protein. It is not the same as Kieselguhr - that’s a filtration aid not an agent
Pros and cons of bentonite
Pros:
- it’s vegan
- no danger of over fining
Cons
- very high power of absorption so can step a wine of fruit on palate and aroma
- leaves a “voluminous deposit” which is difficult to separate from wine
Gelatine is often used in conjunction with which fining aid? Why?
Kieselguhr. Or silica sol.
Used with gelatine for removing other protective colloids from white wines
What is PVPP and what of it used for
Polyvinylpolypyrrolidone
Plastic based fining agent used for removing phenolic compounds, especially colour from slightly oxidised wines
Which wine is activated charcoal permitted to be used for, and what does it do?
White wine. It brightens dull wine by removing colour.