16.1 Skin Contact (white wine making)

Question 1

What is skin contact when referring to WW?

Answer 1

Skin contact is the process of leaving juice in contact with the skins (similar to cold soaking in RWM).

Question 2

What is the purpose of skin contact?

Answer 2

The purpose of skin contact is to extract:
1. Aromas
2. Flavour compounds / precursors
3. Tannin (small amount) for texture

Question 3

What can happen to wine if there is too much skin contact?

Answer 3

If used excessively, skin contact can make wines feel coarse and bitter in the mouth.

Question 4

Name 5 reasons why many white wine styles have zero or minimal skin contact.

Answer 4

TELLTUD
1) Skin contact takes time, uses equipment and labour; not good for cheaper wines meant for quick release and fast profit

2) Complicates logistics, increases cost
3) Under-ripe fruit: skin contact extracts further bitter flavours and astringency

4) Wines meant to be drunk young: any absorbed tannins would not have time to soften

5) Delicate, fruity flavours, minimal colour and mouthfeel are reduced by skin contact

Question 5

In general, is there skin contact when making WW? List 2 methods for keeping skin contact to a minimum.

Answer 5

No. Zero or minimal skin contact.
1) Grapes are crushed as soon as possible
2) Whole bunches can be used to further reduce oxidation

Question 6

What part of the grape holds white wine’s principal desired aromas?

Answer 6

The pulp holds the desired flavours for white wine and not the skin.

Question 7

What does skin contact maximize?

Answer 7

Maximizes flavour extraction

Question 8

Name 5 white varietals are best suited for skin contact? List 2 reasons why they are best suited. What is the danger of doing this?

Answer 8

Riesling, Gewürtz, Viognier, Muscat, Sauvignon Blanc
1) Lots of extractible flavour compounds that are best suited for skin contact
2) These varietals are seldomly matured in oak (kills aromas) so skin contact is a way of enhancing texture

Some WM think skin contact leads to “homogenisation” and reduces variations between grapes / vineyards

Question 9

List two key factors that influence extraction during skin contact.

Answer 9

1. Time
2. Temperature

Question 10

How long are white grapes kept on skins?

Answer 10

1-24+ hours
Greater time = greater extraction of flavour and tannins

Question 11

How does chilling white grape must impact the effectiveness of skin contact?

Answer 11

Chilling during contact reduces extraction of flavours and tannins.

Question 12

Name 2 reasons why white grape juice is chilled to 15°c during skin contact.

Answer 12

1) Permits more control
2) Reduces rate of oxidation and threat of spoilage organisms, including spontaneous fermentation

Question 13

Can white grapes be fermented on skins?

Answer 13

Yes. White grapes can be fermented on skins, just like red grapes.

Question 14

What kind of wine is produced when white grapes are fermented on their skins?

Answer 14

Orange wines.

Question 15

Describe an orange wine (3 points)

Answer 15

1) Orange or amber colour
2) Markedly different taste than WW
* Different aromatic and phenolic compounds extracted from skins
* Dried fruit, dried herbs, hay, nuts
3) Notable tannin

Question 16

How do winemakers create orange wines? (4 points)

Answer 16

1. Often use traditional methods and minimal intervention
2. Ambient yeasts
3. No temperature control
4. No SO2 additions