Flashcards in Finishing and Packaging Deck (65)
All the processes, both physical and chemical, that are used to make wine clear
The process of natural clarification when suspended matter precipitates over time
Why do some premium wineries only clarify through sedimentation?
They believe that they avoid the potential loss of textures and flavors that can happen if a wine is fined or filtered
What is something that must be considered when it comes to only clarifying the wine via sedimentation?
It is really only something that is suitable for premium or super-premium wines due to the amount of time it requires
What is centrifugation?
A rapid process that spins the wine at high rotational speed to clarify it.
What kind of filtration (surface or depth) can centrifugation replace?
- This can allow for early bottling
Is centrifugation something that small wineries can or should do?
Should? Probably not because the machinery required to do this is very expensive, so it generally only done in high volume wineries.
Fining is a procedure in which a fining agent is added to speed up the process of the precipitation of suspended material in the wine.
What is a colloid?
microscopic particles too small to be removed by filtering
What is the aim of fining a wine?
To help clarify the wine and to stabilize it against the formation of hazes later in the bottle
Can you over-fine a wine?
Yes. It is easy to do so many winemakers conduct lab trials before using a fining agent so that they only use the minimum effective amount.
What happens to a wine if it is over fined?
Many fining agents can remove positive compounds from a wine which can make it unstable when too much is added
What are the three categories of common fining agents
- Those that remove unstable proteins
- Those that remove phenolics that contribute undesirable color and bitterness
- Those that remove color and off-odors
Name all of different fining agents
- Egg Whites
- Vegetable protein products
Describe what Bentonite is and how it works as a fining agent
Bentonite is a form of clay which adsorbs unstable proteins and unstable colloidal coloring matter.
- It has a minimal effect on the flavor and texture of a wine.
Are there any negatives to using bentonite?
Yes, it can remove some of the color in red and produces large amounts of sediment, so wine is lost when it is racked off
What are the two forms of egg whites that are used to fine wine?
Fresh or powdered form
How does using egg whites as a fining agent affect the final wine?
It has the ability to remove harsh tannins and clarify wine so the wine comes out clearer and softer. It is also very gentle to the win.
- Egg whites are an allergen so it must be declared on the label if sold in the EU and other places if used above a specific limit.
Gelatin is a fining agent made from _______, and how does it affect red and white wines?
A protein collagen extracted from pork
It removes bitterness and astringency in red wine, and browning in white wine pressings
What is casein?
a milk-derived protein that removes browning in white wines and clarifies wine to some extent.
- Must be declared as an allergen on the label in some territories
What is Isinglass?
A protein collagen made from fish bladders
- must be used in the smallest effective amount possible as it can cause a haze and create a fishy smell
What are the two main types of filtration?
- Depth Filtration
- Surface Filtration
What are the two common forms of depth filtration?
- Diatomaceous Earth (DE)
- Sheet Filters
What is the other name for Diatomaceous Earth?
How does a Rotary Vacuum Filter work?
This type of filter uses a layer of DE to filter the wine. Wine is sucked by vacuum from the outside of the drum, through the DE to the inside of the drum
- This is an oxidative process as the drum is exposed to air
What is the advantage of using an enclosed DE filter?
They work the same, but can be flushed with an inert gas to avoid oxidation taking place
What are the other names for Sheet filters?
- Plate and frame
- 'Pad' filters
How do sheet filters work?
Wine is passed through a sheet of the filtering material. The more sheets there are in the filter the quicker the wine can be filtered.
What are the two types of Surface Filters?
- Membrane Filters
- Cross-flow Filters