D1.C16. Specific Options for White Winemaking Flashcards
What are the aims of skin contact for white wines?
- To enhance the extraction of aroma and flavour compounds and precursors
- To enhance the texture of the wine by extracting a small amount of tannin
What happens if the skin contact is used too excessively for the white wines?
It can make white wines taste bitter and feel coarse in the mouth
Is skin contact a common practice in white winemaking?
No, the majority of white wines are made with zero or very minimal skin contact
What are the advantages of using whole bunches in white winemaking?
- To further limit the contact between the juice and the skins
- To reduce risk of oxidation
- Providing a juice that is low in solids, tannins and color
- The stems provide channels for the juice to drain
In what conditions, minimal skin contact is desired for white winemaking?
- Where delicate fruity flavours, minimal colour and smooth mouthfeel are desired
- For wines that are designed to be drunk early because the tannins that would be extracted during skin contact would not have time to soften
- If fruit is at all under-ripe, as skin contact in this case could extract bitter flavours and astringent tannins
- Inexpensive wines for logistics and cost perspective
When is skin contact preferred?
Skin contact maximises flavour extraction and therefore it is most effectively used on aromatic grape varieties that have lots of aroma compounds that can be extracted, such as Riesling, Gewurztraminer, Viognier, Muscat and Sauvignon Blanc
What are the two main factors that influence extraction during skin contact?
- Time
- Temperature
What are the effects of chilling (usually below 15°C) the must during skin contact?
- Reduces the rate of extraction of flavours and tannins
- Reduces the rate of oxidation
- Reduces the threat of microbiological spoilage
- Reduces the likelihood of spontaneous fermentation
How are “orange” (amber) wines produced?
By fermenting white grapes on their skins
What are the tasting characteristics of orange wines?
Orange wines can have notable levels of tannin and characteristics such as dried fruit, dried herbs, hay or nuts
What are the attitudes of winemakers producing orange wines, in terms of winemaking practices?
They ususally work with traditional methods and minimal intervention, using ambient yeasts, without temperature control or SO2 additions
Why is pressing the white grapes typically be as gentle as possible?
To avoid the extraction of unwanted compounds from the skins and seeds of the grapes, such as tannins and colour
What are the disadvantages of whole bunch pressing?
- It is only an option if the grapes have been hand-harvested
- Whole bunches take up a lot of room in the press, so needs more time and more labour
So whole bunch pressing may be suitable when making smaller batches of premium wines
What is “free run juice”?
It is the juice that can be drained off as soon as the grapes are crushed
What are the properties of free run juice?
- Lowest in solids
- Lowest in colour and tannins
- Lower pH and higher acidity
What happens if the winemaker chooses to make wine from entirely free run juice?
It reduces the final volume of wine that can be produced and therefore has a cost implication
How is press juice different than free run juice?
- At the start, the press juice will be similar to the free run juice, but, as the pressing continues and more pressure is applied, more solids, tannin and colour are extracted
- It has lower acidity and less sugar
What is the advantage of separating the press juice in different fractions (press fractions)?
Different press fractions may be blended with the free run juice in the winemaking and/or maturation process
Why are last press fractions usually discarded?
They are likely to be too astringent or bitter (due to tannins from the skins, seeds or stems)
What is the target of hyperoxidation?
The compounds in the must that oxidise most readily
What is the aim of hyperoxidation?
- The main aim is to produce wines that are more stable against oxidation after fermentation
- It can also help to remove bitter compounds that can come from unripe grape skins, seeds and stems
Why is hyperoxidation typically better suited to less aromatic grape varieties such as Chardonnay?
Because hyperoxidation can destroy some of the most volatile aroma compounds (like the volatile thiols and methoxypyrazines found in Sauvignon Blanc), and therefore would not be carried out if an aromatic fruity or
herbaceous style of this wine was desired
What is the economic burden of hyperoxidation?
It is not particularly expensive, but it is an extra step in the winemaking process that requires labour to set up and monitor so may have some small impact on costs
What is the aim of clarificiation?
To reduce the amount of suspended solids within the must