Fining Agents

Question 1

Colloids in wine

Answer 1

2-1000 nm particle size. Not large enough to be seen and not large enough to be removed by a filter

Question 2

What is fining

Answer 2

The addition of material that will interact with the colloids present in wine

Question 3

Role of charges in fining

Answer 3

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.

Question 4

Allergenic proteins as additives in wine

Answer 4

Quantification of the residual allergenic agents absolutely necessary in order to determine the suitable labeling of wine bottles.

Question 5

Addition of egg proteins

Answer 5

The quantity of dry egg white proteins usually added to red wine ranges 3 and 15 g/hL.

Question 6

What is PVPP used for

Answer 6

prevention not correction

Question 7

What do silica sol’s do

Answer 7

They make sedimentation faster

Question 8

other name of tannins

Answer 8

Procyanidins or proanthocyanins

Question 9

What are the main targets in terms of size of molecules

Answer 9

We want to target smaller tannins, the bigger ones are more round and smooth and we want those

Question 10

Why do we use lysozyme

Answer 10

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

Question 11

What is Casein

Answer 11

Milk

Question 12

Which vegetable proteins are used for fining

Answer 12

Pea and potato protein. Pea leaves weird flavors and aromas especially in white wines so potato protein is better

Question 13

Can we use proteins from wheat

Answer 13

No because of gluten

Question 14

What is GSE and why is it important

Answer 14

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

Question 15

Oenological tannin groups

Answer 15

1. Condensed tannins
2. Hydrolysable tannins (smaller of the two)

Question 16

Why do we do tests with these tannins

Answer 16

to show antioxidant capacity of tannins

Question 17

Skin or seed tannins

Answer 17

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

Question 18

Quebracho

Answer 18

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

Question 19

Importance of Acacia as a new form of tannin

Answer 19

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

Question 20

Grape tannin vs wood tannin

Answer 20

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

Question 21

Oak and chestnut tannin additions

Answer 21

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)

Question 22

OCR

Answer 22

Oxygen Consumption Rate = higher in wood

Question 23

Vine Shoot Tannins

Answer 23

Need to be toasted for activation as well as sanitation. Mainly used for sustainability purposes (Ellagitannins can initiate astringency faster than the other tannins)

Question 24

Perception of astringency from wood

Answer 24

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

Question 25

Grape seed tannin affect on pH and Ethanol

Answer 25

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