Fining Agents Flashcards
Colloids in wine
2-1000 nm particle size. Not large enough to be seen and not large enough to be removed by a filter
What is fining
The addition of material that will interact with the colloids present in wine
Role of charges in fining
If another colloid with the opposite charge is added, the opposite charged molecules attract each other (flocculate) and form a precipitate which can be removed either by allowing it to settle or by filtration.
Allergenic proteins as additives in wine
Quantification of the residual allergenic agents absolutely necessary in order to determine the suitable labeling of wine bottles.
Addition of egg proteins
The quantity of dry egg white proteins usually added to red wine ranges 3 and 15 g/hL.
What is PVPP used for
prevention not correction
What do silica sol’s do
They make sedimentation faster
other name of tannins
Procyanidins or proanthocyanins
What are the main targets in terms of size of molecules
We want to target smaller tannins, the bigger ones are more round and smooth and we want those
Why do we use lysozyme
We use it to kill lactic acid to either prevent or stop MLF
(Made from eggs)
We can also use it to protect the wine after sub-optimal alc ferm or stabilize wine after MLF
What is Casein
Milk
Which vegetable proteins are used for fining
Pea and potato protein. Pea leaves weird flavors and aromas especially in white wines so potato protein is better
Can we use proteins from wheat
No because of gluten
What is GSE and why is it important
Grape Seed Extract. Unwanted side effect is that it can remove anthocyanins. If the tannins are reduced we can reduce acidity as tannins are weak acids and are negatively charged
Oenological tannin groups
- Condensed tannins
- Hydrolysable tannins (smaller of the two)
Why do we do tests with these tannins
to show antioxidant capacity of tannins
Skin or seed tannins
Bigger potential from seeds than skins because seeds have smaller tannins. When you have smaller tannins or shorter chains you have a bigger capacity to scavenge oxygen. Smaller tannins are always more antioxidant
Quebracho
Important as it is a tree with tannins (normally only fruit has tannins) The tree can be used to give the wine an antioxidant capability and is also very cheap
Importance of Acacia as a new form of tannin
Acacia is very close to tannins in tea, this could increase the structure of white wines without having to use wood aging, they are more gentle
Grape tannin vs wood tannin
The antioxidant potential of wood tannin is higher than fruit tannin. This is why we age wine in wood, these tannins are better at scavenging oxygen
Oak and chestnut tannin additions
Oak is expensive and can give vanilla notes
chestnut is cheaper, doesnt impact as muchand is mainly used to protect against oxidation. These additions can be done in lieu of aging in wood or to ensure a shelf life after bottling. (these additions also affect astringency as oak tannins are more aggressive than tannins from grapes)
OCR
Oxygen Consumption Rate = higher in wood
Vine Shoot Tannins
Need to be toasted for activation as well as sanitation. Mainly used for sustainability purposes (Ellagitannins can initiate astringency faster than the other tannins)
Perception of astringency from wood
There is a quicker perception of astringency from wood than grape tannins. Grape tannin astringency occurs later. This can help determine when we would market certain wines
Grape seed tannin affect on pH and Ethanol
Bitterness is not affected by pH
Astringency is less when we have higher pH
Bitterness is more intense with higher alcohol
Astringency is less when we have higher alcohol
